JP7208035B2 - Optical communication device, optical transmitter, and optical transmission control method - Google Patents

Description

The present invention relates to a satellite-mounted optical communication device, an optical transmitter, and an optical transmission control method.

In recent years, with an increase in observation data from earth observation satellites and broadband satellite communication services seen in high-throughput satellites and the like, there is a growing need for large-capacity satellite communication. Expectations are rising for satellite-mounted optical space communication technology (inter-satellite optical communication technology, terrestrial-to-satellite optical communication technology) as a technology to solve this problem.

In order to realize satellite-mounted optical space communication technology, it is necessary to use optical devices and high-speed electronic devices for terrestrial optical communication after improving their reliability for satellite-mounted use. In particular, it is necessary to consider resistance to the space environment in order to ensure reliability for use on satellites.

Radiation can be considered as an effect in the space environment. It has been confirmed in Non-Patent Document 1 that performance degradation and operational abnormalities occur when optical devices for terrestrial optical communication and high-speed electronic devices are irradiated with radiation. 2. Description of the Related Art Optical devices for terrestrial optical communication and high-speed electronic devices use a clock data recovery (CDR) that separates a main signal from a clock, reproduces data, and equalizes the waveform of the main signal. In particular, by irradiating the clock data regenerator with radiation, a single event latch-up (SEL) phenomenon in which the current of the clock data regenerator changes in a stepwise manner and a main event from the clock data regenerator. There have been reports of signal anomalies. Radiation-induced anomalies are also known in SRAM (Static Random Access Memory) type FPGAs (Field-Programmable Gate Arrays), which represent high-speed electronic devices.

Nakamura et al., “Radiation resistance evaluation of optical communication devices for satellite applications”, 62nd Space Science and Technology Joint Lecture, 2G16, 2018

In an optical communication device comprising an optical transmitter and a high-power optical amplifier, when a clock data regenerator is used for high-speed main signal waveform equalization inside the optical transmitter, operation of the clock data regenerator due to radiation There are problems caused by abnormalities.

When a clock data regenerator is used in the optical transmitter, an optical modulated signal is generated by inputting the main signal from the clock data regenerator to the optical modulator. Therefore, if an abnormality occurs in the main signal from the clock data regenerator, the optical signal power of the optical modulated signal input to the high-output optical amplifier may be reduced or interrupted, resulting in an abnormality. In particular, when the main signal is repeatedly interrupted and restored, the optical signal power input to the high-output optical amplifier is repeatedly interrupted and restored, resulting in an optical surge. The occurrence of this optical surge can damage components of high power optical amplifiers.

SUMMARY OF THE INVENTION It is an object of the present invention to prevent an optical surge caused by main signal abnormality caused by radiation of a clock data regenerator and to protect a high output optical amplifier.

An optical communication apparatus according to the present invention includes a signal generator that generates a main signal, a clock data regenerator that equalizes the waveform of the main signal, a transmission laser that outputs laser light, and a main signal whose waveform is equalized. A phase modulating unit for phase-modulating the laser beam based on the signal and outputting an optical phase-modulated signal, a high-output optical amplifier for amplifying the optical phase-modulated signal with high output, and a current abnormality in the clock data regenerator. a clock data regenerator current anomaly detector for detecting and shutting down the high-output optical amplifier and the signal generating unit; and a main signal interruption of the main signal from the clock data regenerator and and a clock/data regenerator power control unit that stops power supply to the clock/data regenerator after shutting down the high-output optical amplifier and the signal generation unit.

Further, an optical transmitter according to the present invention is an optical transmitter for outputting an optical phase modulated signal to a high-output optical amplifier, comprising: a signal generator for generating a main signal; and clock data for equalizing the waveform of the main signal. a regenerator, a transmission laser unit that outputs laser light, a phase modulation unit that phase-modulates the laser light based on a waveform-equalized main signal and outputs the optical phase-modulated signal, and the clock data regenerator and a clock data regenerator current anomaly detector for shutting down the high-output optical amplifier and the signal generator, and a main signal interruption of the main signal from the clock data regenerator to detect the high-output a signal interruption detection unit for shutting down the optical amplifier and the signal generation unit; and a clock data regenerator power supply control unit for stopping power supply to the clock data regenerator after shutting down the high-output optical amplifier and the signal generation unit. have.

An optical transmission control method according to the present invention is an optical transmission control method for the above optical communication apparatus, wherein an abnormality in the current of the clock data regenerator is detected, and main signal interruption of the main signal is detected from the clock data regenerator. detecting and shutting down the high-power optical amplifier and the signal generator based on at least one of detection of the current anomaly of the clock data regenerator and detection of the main signal loss from the clock data regenerator; After shutting down the high output optical amplifier and the signal generator, the power supply to the clock data regenerator is stopped.

According to the optical communication device, the optical transmitter, or the optical transmission control method according to the present invention, it is possible to prevent the optical surge caused by the abnormality of the main signal due to the radiation of the clock data regenerator, and the high-output optical amplifier and the high-output optical amplifier. protection of the device affected by the output of Examples of devices that are affected by the output of a high-power optical amplifier include an optical acquisition and tracking device that constitutes an optical communication device on the transmitting side, an optical acquisition and tracking device that constitutes an optical communication device on the receiving side, a low-noise optical amplifier, and an optical amplifier. receiver, etc.

1 is a configuration diagram showing an outline of an optical communication device of the present invention; FIG. 2 is a flowchart for explaining an optical transmission control method of the optical communication device 1 of FIG. 1; 1 is a configuration diagram of an optical communication device 50 according to a first embodiment of the present invention; FIG. FIG. 4 is a configuration diagram of a high-power optical amplifier 40 of FIG. 3; 4 is a flowchart for explaining an optical transmission control method according to the first embodiment; 9 is a flowchart for explaining a modification of the optical transmission control method of the first embodiment; FIG. 4 is a configuration diagram of an optical communication device 50a according to a first modification of the first embodiment; FIG. 9 is a configuration diagram of an optical communication device 50b according to a second modification of the first embodiment; FIG. 5 is a configuration diagram of an optical communication device 50c according to a second embodiment of the present invention; 9 is a flowchart for explaining an optical transmission control method according to the second embodiment; 9 is a flowchart for explaining a modification of the optical transmission control method of the second embodiment; FIG. 11 is a configuration diagram of an optical communication device 50d according to a first modified example of the second embodiment; FIG. 11 is a configuration diagram of an optical communication device 50e according to a second modification of the second embodiment; FIG. 11 is a configuration diagram of an optical communication device 50f according to a third embodiment of the present invention; FIG. 13 is a configuration diagram of a phase modulation unit in FIG. 12; FIG. 13 is a configuration diagram of a modification of the phase modulating section of FIG. 12; 11 is a flow chart for explaining a first optical transmission control method according to the third embodiment; FIG. 11 is a flow chart for explaining a modification of the first optical transmission control method of the third embodiment; FIG. 10 is a flowchart for explaining a second optical transmission control method of the third embodiment; It is a figure which shows the generation principle of the optical phase modulation signal output from a phase modulation part. FIG. 17 is a diagram showing the control operation in step S347 of FIG. 16; FIG. 11 is a flowchart for explaining a third optical transmission control method of the third embodiment; FIG. It is a figure which shows the generation principle of the optical intensity modulation signal output from an intensity modulation|alteration part. FIG. 19 is a diagram showing a control operation in step S367 of FIG. 18; FIG. 11 is a configuration diagram of an optical communication device 50g according to a first modified example of the third embodiment; FIG. 11 is a configuration diagram of an optical communication device 50h according to a second modified example of the third embodiment; FIG. 11 is a configuration diagram of an optical communication device 50i according to a fourth embodiment of the present invention; 23 is a configuration diagram of an IQ modulation unit in FIG. 22; FIG. FIG. 23 is a configuration example of a modified example of the IQ modulation section of FIG. 22. FIG. FIG. 11 is a flow chart for explaining a first optical transmission control method of the fourth embodiment; FIG. FIG. 11 is a flow chart for explaining a modification of the first optical transmission control method of the fourth embodiment; FIG. FIG. 14 is a flow chart for explaining a second optical transmission control method of the fourth embodiment; FIG. FIG. 11 is a configuration diagram of an optical communication device 50j according to a first modified example of the fourth embodiment; FIG. 11 is a configuration diagram of an optical communication device 50k according to a second modification of the fourth embodiment;

<Overview of the present invention>
First, a schematic configuration of an embodiment of the present invention will be described. FIG. 1 is a configuration diagram showing an outline of an optical communication device according to the present invention. The optical communication device 1 has a transmitting side and a receiving side, and only the transmitting side is shown in the present invention, and the same applies hereinafter. As shown in FIG. 1, the optical communication device 1 includes a signal generation unit 11, a clock data regenerator 12, a transmission laser unit 13, a phase modulation unit 14, a clock data regenerator current anomaly detection unit 15, and a signal It has an optical transmitter 2 having a disconnection detector 16 , a clock data regenerator power supply controller 17 , and a high output optical amplifier 18 .

The signal generation unit 11 generates the main signal I1 by converting the input data D1 into the main signal I1. The main signal I1 is input to the clock data regenerator 12, and the clock data regenerator 12 performs waveform equalization of the main signal I1. The waveform-equalized main signal is input to the phase modulating section 13 . The transmission laser unit 13 outputs laser light. On the other hand, the output laser light is input to the phase modulating section 14 . The phase modulation unit 14 phase-modulates the laser light based on the waveform-equalized main signal and outputs an optical phase-modulated signal. The optical phase modulated signal is input to the high power optical amplifier 18, and the high power optical amplifier 18 amplifies the optical phase modulated signal to high power. The optical phase-modulated signal that has undergone high-output optical amplification is output from the optical communication device 1 .

A current value flowing through the clock data regenerator 12 is input to the clock data regenerator current anomaly detector 15, and when an anomaly in the current of the clock data regenerator 12 occurs, the clock data regenerator current anomaly detector 15 is detected and the high power optical amplifier 18 is shut down. The abnormal current in the clock data regenerator 12 is, for example, a state in which latch-up occurs and the current value in the clock data regenerator 12 rises significantly from the normal value. The clock data regenerator current anomaly detector 15 has, for example, a monitor circuit (not shown) that detects the current flowing through the clock data regenerator 12, and the current value rises significantly from the normal value with reference to the threshold value. A current anomaly may be detected by detecting the state of The same applies to the clock data regenerator current abnormality detectors of the following embodiments. Further, upon detecting a current anomaly, the clock data regenerator current anomaly detector 15 outputs, for example, a shutdown signal SD1 to the high-output optical amplifier 18 . Upon receiving the shutdown signal SD1, the high-output optical amplifier 18 shuts down, for example, by stopping the internal power supply or setting the laser current value of the internal excitation laser to zero.

The clock data regenerator current abnormality detector 15 also outputs the shutdown signal SD1 to the signal generator 11 as well. Upon receiving the shutdown signal SD1, the signal generator 11 stops generating the main signal I1. The clock data regenerator current anomaly detection unit 15 then notifies the clock data regenerator power supply control unit 16 of the detection of the current anomaly.

Further, the signal interruption detector 16 monitors the input of the main signal from the signal generator 11 to the clock data regenerator 12, detects the interruption of the main signal, and detects the current abnormality of the clock data regenerator. Similar to the unit 15, the high-power optical amplifier 18 is shut down by outputting the shutdown signal SD1 to the high-power optical amplifier 18, for example. The signal interruption of the clock data regenerator 12 is, for example, a state in which the main signal is no longer output from the signal generator and no main signal is input to the clock data regenerator 12 . The clock data regenerator 12 generally has a function of detecting an input signal loss and outputting an alarm signal. good. The same applies to the signal interruption detectors of the following embodiments. The signal interruption detection section 16 also outputs the shutdown signal SD1 to the signal generation section 11, and after transmitting the shutdown signal SD1, transmits a signal interruption detection signal to the clock data regenerator power supply control section 17. FIG.

The clock data regenerator power control unit 17 stops the power supply to the clock data regenerator 12 after the high output optical amplifier 18 and the signal generation unit 11 are shut down. Specifically, for example, when the clock data regenerator power supply control unit 16 receives the current abnormality detection signal or the signal interruption detection signal, it controls the power supply of the clock data regenerator to supply the power supply voltage to the clock data regenerator 12 . Stop.

FIG. 2 is a flow chart for explaining the optical transmission control method of the optical communication device 1 of FIG. First, the clock data regenerator current anomaly detector 15 determines whether or not an anomaly in the current of the clock data regenerator 12 is detected (step S11). The signal generator 11 is shut down (step S14). The clock data regenerator current anomaly detection unit 15 then notifies the clock data regenerator power supply control unit 17 of the current anomaly detection, and the clock data regenerator power supply control unit 17 controls the power supply to the clock data regenerator 12. The voltage supply is stopped (step S15).

Further, if no current abnormality is detected in step S11, the signal break detector 16 determines whether the main signal break of the main signal input from the signal generator 11 to the clock data regenerator 12 has been detected from the clock data regenerator. (Step S12). When the signal interruption detector 16 detects the main signal interruption, it shuts down the high-output optical amplifier 18 (step S13) and shuts down the signal generator 11 (step S14), similarly to the clock data regenerator current abnormality detector 15. ).

Further, the signal interruption detection unit 16 then notifies the clock data regenerator power supply control unit 17 of the current abnormality detection, and the clock data regenerator power supply control unit 17 supplies the power supply voltage to the clock data regenerator 12. is stopped (step S15). If the interruption of the main signal is not detected in step S12, the process returns to step S11 to determine whether the clock data regenerator current anomaly detector 15 has detected an anomaly in the current of the clock data regenerator 12 or not.

Thus, according to the present invention, the high-output optical amplifier 18 is controlled based on at least one of detection of a current anomaly in the clock data regenerator 12 and detection of main signal interruption of the main signal from the clock data regenerator 12 . And the signal generator 11 is shut down, and the power supply to the clock data regenerator 12 is stopped after the shutdown. With this configuration, when an abnormality in the clock data regenerator 12 is detected, the high-output optical amplifier 18 is shut down and the main signal is stopped immediately. can be prevented, and the protection of the high-output optical amplifier 18 can be realized.

<First Embodiment: Optical Communication Device 50>
Next, an optical communication device according to the first embodiment of the present invention will be described. FIG. 3 is a configuration diagram of the optical communication device 50 according to the first embodiment of the present invention. The optical phase-modulated signal is a single-polarized binary phase-shift-keyed signal (BPSK: Binary Phase Shift Keying). The optical communication device 50 has an optical transmitter 10 and a high power optical amplifier 40 . The optical transmitter 10 has a digital signal processing section 20 and an optical transmission section 30 .

The digital signal processing section 20 has a signal generation section 210 , a signal interruption detection section 220 , a clock data regenerator power supply control section 230 , and a clock data regenerator current abnormality detection section 240 . Here, the digital signal processing unit 20 may be an SRAM type FPGA or the like used on the ground. The optical transmission section 30 has a transmission laser section 310 , a phase modulation section 320 , a clock data regenerator 330 , a clock data regenerator current monitoring section 340 , and a clock data regenerator power supply section 350 .

The signal generator 210 converts the input data D1 into the main signal I1 to generate the main signal.
The main signal I1 is input to the clock data regenerator 330, and the clock data regenerator 330 performs waveform equalization of the main signal I1. The waveform-equalized main signal is input to the phase modulating section 320 . The transmission laser unit 310 outputs laser light. On the other hand, the output laser light is input to phase modulating section 320 .

The phase modulation section 320 modulates the laser light based on the waveform-equalized main signal and outputs an optical phase-modulated signal. The optical phase modulated signal is input to the high power optical amplifier 40, and the high power optical amplifier 40 amplifies the optical phase modulated signal to high power. The high-output optically amplified optical phase-modulated signal is output from the optical communication device 50 .

The clock data regenerator current monitoring unit 340 monitors the current flowing through the clock data regenerator 330 and outputs the current value to the clock data regenerator current abnormality detection unit 240 . When the current abnormality of the clock data regenerator 330 occurs, the clock data regenerator current abnormality detector 240 detects the current abnormality of the clock data regenerator 330 and outputs a shutdown signal SD1 to the high-power optical amplifier 40 and the signal generator 210. to shut down the high-power optical amplifier 40 and the signal generator 210 . After transmitting the shutdown signal SD1 to the high-output optical amplifier 40 and the signal generator 210, the clock data regenerator current anomaly detector 240 transmits a current anomaly detection signal to the clock data regenerator power controller 230. FIG. Upon receiving the shutdown signal SD1, the signal generator 210 stops generating the main signal I1. Note that the clock data regenerator current abnormality detection section 240 may also transmit the shutdown signal SD1 to the transmission laser section 310 to shut down the transmission laser section 310 .

On the other hand, when the main signal I1 input to the clock data regenerator 330 is interrupted, the signal interruption detection unit 220 detects the signal interruption and transmits a shutdown signal SD1 to the high-output optical amplifier 40 to turn off the high-output light. Shut down the amplifier 40. Note that the signal interruption detection section 220 may also transmit the shutdown signal SD1 to the signal generation section 210 and the transmission laser section 310 to shut them down. After transmitting the shutdown signal SD 1 to the high-output optical amplifier 40 , the signal interruption detection section 220 transmits a signal interruption detection signal to the clock data regenerator power supply control section 230 .

The clock data regenerator power supply control unit 230 sends a shutdown signal SD2 to the clock data regenerator power supply unit 350 when receiving the current abnormality detection signal or the signal interruption detection signal after shutting down the high output optical amplifier and the signal generation unit. Then, the power supply to the clock data regenerator 330 is stopped. The clock data regenerator power supply unit 350 stops supplying the power supply voltage to the clock data regenerator 330 upon receiving the shutdown signal SD2.

The optical transmitter 30 may have an intensity modulator instead of the phase modulator 320, and the intensity modulator may output an optical intensity modulated signal. The transmission laser unit 310 may be configured to be shut down after receiving the shutdown signal SD1.

The digital signal processing unit 20 has a clock generation unit that generates a clock signal, the optical transmission unit 30 has an intensity modulation unit after the phase modulation unit 320, and the clock generation unit intensity-modulates the clock signal. A configuration may be employed in which an RZ (Return-to-zero) modulated signal is output by inputting to the unit.

FIG. 4 is a block diagram of the high output optical amplifier 40 of FIG. The high-output optical amplifier 40 includes a power supply section 410, an excitation laser control section 420, an excitation laser current control section 430a and an excitation laser current control section 430b, a digital/analog converter 440a and a digital/analog converter 440b, an excitation It has laser sections 450 a and 450 b , a pre-light amplification section 460 and a booster light amplification section 470 .

The optical phase-modulated signal from the optical transmitter 10 is input to the pre-optical amplification section 460 together with the excitation laser light from the excitation laser section 450a, and the pre-optical amplification section 460 performs optical amplification. The optical phase-modulated signal optically amplified by the pre-optical amplifier 460 is output to the booster optical amplifier 470, and the booster optical amplifier 470 converts the optical phase-modulated signal optically amplified by the pre-optical amplifier 460 into a high-output optical amplifier. do. The high-output optically amplified optical phase-modulated signal is output from the optical communication device 50 .

A shutdown signal SD1 from the optical transmitter 10 is input to the high-power optical amplifier 40 and received by the excitation laser controller 420 . Upon receiving the shutdown signal SD1, the excitation laser control section 420 instructs the power supply section 410 to stop the power supply, or causes the excitation laser current control sections 430a and 430b to turn on the excitation laser section through the digital/analog converters 440a and 440b. An instruction is given to set the laser current values of 450a and 450b to zero. As a result, laser light is not output from the pump laser sections 450a and 450b, and optical amplification of the pre-optical amplification section 460 and the high-output optical amplification of the booster optical amplification section 470 inside the high-output optical amplifier 40 are stopped.

<First Embodiment: System Operation>
FIG. 5A is a flow chart explaining the optical transmission control method of the first embodiment. This flowchart is executed when an abnormality due to the influence of radiation occurs while the optical transmitter 10 inside the optical communication device 50 and the high-output optical amplifier 40 are operating normally.

In step S<b>101 , the clock data regenerator current monitoring unit 340 monitors the current of the clock data regenerator 330 , and the signal interruption detection unit 220 monitors the main signal I<b>1 of the signal generation unit 210 . In step S102, if the clock data regenerator current anomaly detector 240 detects an anomaly in the current of the clock data regenerator 330, the process proceeds to step S104.

If no current abnormality is detected in step S102, the process proceeds to step S103. In step S103, if the signal interruption detection unit 220 detects the signal interruption of the signal generation unit 210, the process proceeds to step S104. If no signal interruption is detected in step S103, the process returns to step S101 to monitor the current of the clock data regenerator 330 and the main signal I1 of the signal generator 210. FIG.

In step S104, the clock data regenerator current abnormality detector 240 or signal interruption detector 220 transmits a shutdown signal SD1 to the high-output optical amplifier 40, and the process proceeds to step S105 or step S106. In step S105, the excitation laser control unit 420 stops supplying voltage to the power supply unit 410 in the high-output optical amplifier 40, shuts down the high-output optical amplifier 40, and proceeds to step S107. In step S106, the excitation laser control unit 420 stops current supply to the excitation laser units 450a and 450b in the high-power optical amplifier 40, shuts down the high-power optical amplifier 40, and proceeds to step S107.

If no signal interruption is detected in step S107, the process proceeds to step S108, the clock data regenerator current abnormality detection unit 240 or signal interruption detection unit 220 transmits a shutdown signal SD1 to the signal generation unit 210, and the process proceeds to step S109. move on. If signal disconnection is detected in step S107, the process proceeds to step S109. In step S109, the clock data regenerator power control unit 230 stops power supply to the clock data regenerator 330, and the process proceeds to step S110. In step S110, the clock data regenerator current abnormality detection unit 240 or the signal interruption detection unit 220 shuts down the transmission laser unit 310. FIG. This is the end of this flowchart.

In step S106, the pumping laser control unit 420 may stop the current supply only to the pumping laser unit 450b required for high-output light amplification by the booster light amplifier unit 470. FIG.

As described above, according to the first embodiment, based on at least one of detection of an abnormality in the current of the clock data regenerator 330 and detection of main signal interruption of the main signal from the clock data regenerator 330, the high The output optical amplifier 40 and the signal generator 210 are shut down, and after the shutdown, the power supply to the clock data regenerator 330 is stopped. With this configuration, when an abnormality in the clock data regenerator 330 is detected, the high-output optical amplifier 40 is quickly shut down and the main signal is stopped. Therefore, it is possible to prevent the optical surge caused by the abnormality of the main signal caused by the radiation of the clock data regenerator, and the protection of the high-output optical amplifier 40 can be realized.

In the above description of the optical transmission control method, the high-output optical amplifier 40 and the signal generator 210 are shut down, the power supply to the clock data regenerator 330 is stopped, and then the transmission laser unit 310 is shut down. The order is not limited.

FIG. 5B is a flowchart illustrating a modification of the optical transmission control method of the first embodiment; This flowchart is executed when an abnormality due to the influence of radiation occurs while the optical transmitter 10 inside the optical communication device 50 and the high-output optical amplifier 40 are operating normally.

In step S121, the clock data regenerator current monitoring unit 340 monitors the current of the clock data regenerator 330, and the signal interruption detection unit 220 monitors the main signal I1 of the signal generation unit 210. FIG. In step S122, if the clock data regenerator current anomaly detector 240 detects the current anomaly of the clock data regenerator 330, the process proceeds to step S124.

If no current abnormality is detected in step S122, the process proceeds to step S123. In step S123, if the signal interruption detection unit 220 detects the signal interruption of the signal generation unit 210, the process proceeds to step S124. If no signal interruption is detected in step S123, the process returns to step S121 to monitor the current of the clock data regenerator 330 and the main signal I1 of the signal generator 210. FIG.

In step S124, the clock data regenerator current abnormality detection unit 240 or the signal interruption detection unit 220 transmits a shutdown signal SD1 to the transmission laser unit 310, shuts down the transmission laser unit 310, and proceeds to step S125.

If no signal interruption is detected in step S125, the process proceeds to step S126, the clock data regenerator current abnormality detection unit 240 or signal interruption detection unit 220 transmits a shutdown signal SD1 to the signal generation unit 210, and the process proceeds to step S127. move on. If signal disconnection is detected in step S125, the process proceeds to step S127. In step S127, the clock data regenerator power control unit 230 stops power supply to the clock data regenerator 330, and the process proceeds to step S128.

In step S128, the clock data regenerator current abnormality detector 240 or signal interruption detector 220 transmits a shutdown signal SD1 to the high-output optical amplifier 40, and the process proceeds to step S129 or step S130. In step S<b>129 , the excitation laser control unit 420 stops supplying voltage to the power supply unit 410 in the high-power optical amplifier 40 and shuts down the high-power optical amplifier 40 . In step S130, the excitation laser control section 420 stops current supply to the excitation laser sections 450a and 450b in the high-power optical amplifier 40 and shuts down the high-power optical amplifier 40. FIG. This is the end of this flowchart.

Thus, even if the transmission laser unit 310 is first shut down, the power supply to the clock data regenerator 330 is stopped, and the high output optical amplifier 40 and the signal generation unit 210 are shut down, optical surge can be prevented and the high output optical amplifier can be prevented. protection can be realized.

<Modified Example of First Embodiment: Optical Communication Devices 50a and 50b>
A modification of the optical communication device according to the first embodiment of the present invention will be described. FIG. 6 is a configuration diagram of an optical communication device 50a according to a first modification of the first embodiment. The optical transmitter 10 a has a digital signal processing section 20 a , a radiation-resistant digital signal processing section 21 and an optical transmission section 30 . Here, the radiation-tolerant digital signal processing unit 21 indicates an FPGA or the like that has a track record of being mounted on a satellite and has radiation resistance. FIG. 6 shows a case where the clock data regenerator power supply controller 230 is included in the radiation-tolerant digital signal processor 21 . Operation processing of the optical communication device 51 is the same as that of the first embodiment.

FIG. 7 is a configuration diagram of an optical communication device 50b according to a second modification of the first embodiment. The optical transmitter 10b has a digital signal processing section 20b, a radiation-resistant digital signal processing section 21a, and an optical transmission section 30. FIG. Here, the radiation-tolerant digital signal processing unit 21a indicates a radiation-tolerant FPGA or the like that has a track record of being mounted on a satellite. FIG. 7 shows a case where the signal interruption detector 220, the clock data regenerator power supply controller 230, and the clock data regenerator current abnormality detector 240 are included in the radiation-resistant digital signal processor 21a. Operation processing of the optical communication device 52 is the same as that of the first embodiment.

These modified examples provide the same effects as the first embodiment, and use of the radiation-resistant digital signal processing unit enables reliable detection of main signal abnormalities due to radiation.

<Second Embodiment: Optical Communication Device 50c>
An optical communication device according to a second embodiment of the present invention will be described. FIG. 8 is a configuration diagram of an optical communication device 50c according to the second embodiment of the present invention. In this embodiment, the optical phase-modulated signal is a single-polarized quadrature phase shift keying (QPSK) signal. As shown in FIG. 8, the signal generation unit 210a generates a plurality of main signals I1 and I2, and the clock data regenerator 331 includes a plurality of clock data regenerating circuits that equalize the waveforms of the plurality of main signals I1 and I2. 330a and 330b.

The clock data regenerator current anomaly detector 240a detects current anomalies in the plurality of clock data regenerators 330a and 330b and shuts down the high output optical amplifier 40 and the signal generator 210a. The main signal interruption of the main signals I1 and I2 is detected to shut down the high output optical amplifier 40 and the signal generator 210a. Further, in the present embodiment, at least detection of a current abnormality in one of the plurality of clock data recovery circuits 330a and 330b and disconnection of one of the plurality of main signals from the clock data recovery circuits 330a and 330b. Based on one, the high power optical amplifier 40 and the signal generator 210a are shut down.

The optical communication device 50 c has an optical transmitter 10 c and a high power optical amplifier 40 . The optical transmitter 10 c has a digital signal processing section 20 c and an optical transmission section 30 .

The digital signal processing section 20c has a signal generation section 210a, a signal interruption detection section 220a, a clock data regenerator power supply control section 230a, and a clock data regenerator current abnormality detection section 240a. Here, the digital signal processing unit 20c indicates an SRAM type FPGA or the like used on the ground. The optical transmission unit 30a includes a transmission laser unit 310, an IQ modulation unit 360, a clock data regenerator 331 having clock data regenerators 330a and 330b, a clock data regenerator current monitoring unit 340a, and a clock data regenerator power supply. and a portion 350a.

Input data D1 and D2 are converted into main signals I1 and I2 in the signal generator 210a. The main signals I1 and I2 are input to clock data recovery circuits 330a and 330b, and the waveforms of the main signals I1 and I2 are equalized. The waveform-equalized main signals I1 and I2 are input to the IQ modulation section 360 . A laser beam is output from the transmission laser unit 310 . On the other hand, the output laser light is input to the IQ modulation section 360 . The IQ modulation section 360 modulates the laser light based on the main signals I1 and I2, and outputs an optical phase modulated signal. The optical phase-modulated signal is input to the high-power optical amplifier 40 and is amplified by high-power light. The high-power optically amplified optical phase-modulated signal is output from the optical communication device 53 .

The currents flowing through the clock data recovery circuits 330a and 330b are monitored by the clock data recovery current monitor 340a. When a current abnormality occurs in the clock data recovery circuits 330a and 330b, the clock data recovery device current abnormality detection section 240a detects the current abnormality, and after transmitting a shutdown signal SD1 to the high-output optical amplifier 40 and the signal generation section 210a, A current abnormality detection signal is transmitted to the clock data regenerator power supply control unit 230a. Upon receiving the shutdown signal SD1, the signal generator 210a stops generating the main signals I1 and I2. The clock data regenerator current abnormality detection section 240a may also transmit the shutdown signal SD1 to the transmission laser section 310 to shut down the transmission laser section 310. FIG.

On the other hand, when the main signal I1 or I2 input to the clock data recovery circuits 330a and 330b is interrupted, the signal interruption detector 220a detects the signal interruption and transmits a shutdown signal SD1 to the high-output optical amplifier 40. After that, a signal interruption detection signal is transmitted to the clock data regenerator power control unit 230a. Note that the signal interruption detection section 220 may send the shutdown signal SD1 not only to the high-output optical amplifier 40 but also to the signal generation section 210a and the transmission laser section 310 to shut them down. When the clock data regenerator power supply control unit 230a receives the current abnormality detection signal or the signal interruption detection signal, it transmits a shutdown signal SD2 to the clock data regenerator power supply unit 350a. When the clock data regenerator power supply unit 350a receives the shutdown signal SD2, it stops supplying the power supply voltage to the clock data regenerator circuits 330a and 330b.

The digital signal processing unit 20c has a clock generation unit that generates a clock signal, the optical transmission unit 30a is configured to have an intensity modulation unit after the IQ modulation unit 360, and the clock generation unit intensity-modulates the clock signal. A configuration may be employed in which an RZ (Return-to-zero) modulated signal is output by inputting to the unit. The transmission laser unit 310 may be configured to be shut down after receiving the shutdown signal SD1.

As for the operation of the high-output optical amplifier 40, processing similar to that of the optical communication device 50 of the first embodiment is performed.

Although an example has been given for a QPSK signal, it is also applicable to optical signals of M-PSK in which M is four or more, M-QAM (Quadrature Amplitude Modulation), and M-APSK (Amplitude Phase Shift Keying).

<Second Embodiment: System Operation>
FIG. 9 is a flow chart for explaining the optical transmission control method of the second embodiment. This flowchart is executed when an abnormality due to the influence of radiation occurs while the optical transmitter 10c inside the optical communication device 50c and the high-output optical amplifier 40 are operating normally.

In step S201, the clock data regenerator current monitoring section 340a monitors the currents of the clock data regenerating circuits 330a and 330b, and the signal interruption detection section 220a monitors the main signals I1 and I2 of the signal generation section 210a. In step S202, if the clock data regenerator current abnormality detector 240a detects a current abnormality in the clock data regenerator circuit 330a or 330b, the process proceeds to step S204.

If no current abnormality is detected in step S202, the process proceeds to step S203. In step S203, if the signal disconnection detection unit 220a detects signal disconnection of the signal generation unit 210a, the process proceeds to step S204. If no signal loss is detected in step S203, the process returns to step S201, the clock data regenerator current monitoring unit 340a monitors the currents of the clock data recovery circuits 330a and 330b, and the signal loss detection unit 220a detects the main signal of the signal generation unit 210a. Monitor I1 and I2.

In step S204, the clock data regenerator current abnormality detection unit 240a or the signal interruption detection unit 220a transmits the shutdown signal SD1 to the high-output optical amplifier 40 and the signal generation unit 210a, and the process proceeds to step S205 or step S206. In step S205, the excitation laser control unit 420 stops supplying voltage to the power supply unit 410 in the high-output optical amplifier 40, shuts down the high-output optical amplifier 40, and proceeds to step S207. In step S206, the excitation laser control unit 420 stops current supply to the excitation laser units 450a and 450b in the high-power optical amplifier 40, shuts down the high-power optical amplifier 40, and proceeds to step S207.

If no signal interruption is detected in step S207, the process proceeds to step S208, in which the clock data regenerator current abnormality detection unit 240 or the signal interruption detection unit 220a transmits the shutdown signal SD1 to the signal generation unit 210a, and the main signal I1 and I2 are stopped and the process proceeds to step S209. If signal disconnection is detected in step S207, the process proceeds to step S209. In step S209, the clock data regenerator power control unit 230a stops the power supply to the clock data regenerators 330a and 330b, and the process proceeds to step S210. In step S210, the transmission laser section 310 is shut down. This is the end of this flowchart.

In step S206, the pumping laser control unit 420 may stop the supply of current only to the pumping laser unit 450b required for high-output light amplification by the booster light amplifier unit 470. FIG.

As described above, according to the second embodiment, detection of current abnormality in one of the plurality of clock data recovery circuits 330a and 330b and detection of one of the plurality of main signals from the clock data recovery circuits 330a and 330b The high-power optical amplifier 40 and the signal generator 210a are shut down based on at least one of detection of signal loss. Power supply to the clock data recovery circuits 330a and 330b is then stopped. With this configuration, when an abnormality in the clock data recovery circuits 330a and 330b is detected, the high-output optical amplifier 40 is shut down and the main signal is stopped immediately. Therefore, according to the second embodiment, as in the first embodiment, it is possible to prevent the optical surge caused by the main signal abnormality due to the radiation of the clock data recovery circuits 330a and 330b, and to realize the protection of the high-output optical amplifier 40. .

In the above description of the optical transmission control method, the high-output optical amplifier 40 and the signal generation section 210a are shut down, the power supply to the clock data recovery circuits 330a and 330b is stopped, and then the transmission laser section 310 is shut down. , but not limited to this order.

FIG. 9B is a flowchart explaining a modification of the optical transmission control method of the second embodiment. This flowchart is executed when an abnormality due to the influence of radiation occurs while the optical transmitter 10c inside the optical communication device 50c and the high-output optical amplifier 40 are operating normally.

In step S221, the clock data regenerator current monitoring section 340a monitors the currents of the clock data regenerating circuits 330a and 330b, and the signal disconnection detection section 220a monitors the main signals I1 and I2 of the signal generating section 210a. In step S222, if the clock data regenerator current anomaly detector 240a detects an anomaly in the currents of the clock data regenerators 330a and 330b, the process proceeds to step S224.

If no current abnormality is detected in step S222, the process proceeds to step S223. In step S223, if the signal disconnection detection unit 220a detects signal disconnection of the signal generation unit 210a, the process proceeds to step S224. If no signal interruption is detected in step S223, the process returns to step S221 to monitor the currents of the clock data recovery circuits 330a and 330b and the main signals I1 and I2 of the signal generator 210a.

In step S224, the clock data regenerator current monitoring unit 340a or the signal interruption detection unit 220a transmits a shutdown signal SD1 to the transmission laser unit 310, shuts down the transmission laser unit 310, and proceeds to step S125.

If no signal interruption is detected in step S225, the process proceeds to step S226, the clock data regenerator current abnormality detection unit 240a or the signal interruption detection unit 220a transmits the shutdown signal SD1 to the signal generation unit 210a, and the process proceeds to step S227. move on. If signal interruption is detected in step S225, the process proceeds to step S127. In step S127, the clock data regenerator power control unit 230a stops power supply to the clock data regenerators 330a and 330b, and the process proceeds to step S228.

In step S228, the clock data regenerator current abnormality detector 240a transmits the shutdown signal SD1 to the high-power optical amplifier 40, and the process proceeds to step S229 or step S230. In step S<b>229 , the excitation laser controller 420 stops supplying voltage to the power supply unit 410 in the high-power optical amplifier 40 and shuts down the high-power optical amplifier 40 . In step S230, the excitation laser control section 420 stops current supply to the excitation laser sections 450a and 450b in the high-power optical amplifier 40 and shuts down the high-power optical amplifier 40. FIG. This is the end of this flowchart.

Thus, even if the transmission laser unit 310 is first shut down, the power supply to the clock data recovery circuits 330a and 330b is stopped, and then the high-output optical amplifier 40 and the signal generation unit 210a are shut down, optical surges can be prevented. A high power optical amplifier and protection of devices affected by the output of the high power optical amplifier can be achieved. Examples of devices that are affected by the output of a high-power optical amplifier include an optical acquisition and tracking device that constitutes an optical communication device on the transmitting side, an optical acquisition and tracking device that constitutes an optical communication device on the receiving side, a low-noise optical amplifier, and an optical amplifier. receiver, etc.

<Modified Example of Second Embodiment: Optical Communication Devices 50d and 50e>
A modification of the optical communication device according to the second embodiment of the present invention will be described. FIG. 10 is a configuration diagram of an optical communication device 50d according to the first modification of the second embodiment. The optical transmitter 10 d has a digital signal processing section 20 d , a radiation-resistant digital signal processing section 21 b and an optical transmission section 30 . Here, the radiation-tolerant digital signal processing unit 21b is a radiation-tolerant FPGA or the like that has a track record of being mounted on a satellite. FIG. 10 shows a case where the clock data regenerator power supply controller 230a is included in the radiation-tolerant digital signal processor 21b. Operation processing of the optical communication device 50d is the same as that of the second embodiment.

FIG. 11 is a configuration diagram of an optical communication device 50e according to a second modification of the second embodiment. The optical transmitter 10 e has a digital signal processing section 20 e , a radiation-resistant digital signal processing section 21 c and an optical transmission section 30 . FIG. 11 shows a case where the signal interruption detection section 220a, the clock data regenerator power supply control section 230a, and the clock data regenerator current abnormality detection section 240a are included in the radiation-resistant digital signal processing section 21c. The operation processing of the optical communication device 50e is the same as that of the second embodiment.

These modified examples provide the same effects as the second embodiment, and use of the radiation-resistant digital signal processing unit makes it possible to reliably detect main signal abnormalities due to radiation.

<Third Embodiment: Optical Communication Device 50f>
An optical communication device according to a third embodiment of the present invention will be described. FIG. 12 is a configuration diagram of an optical communication device 50f according to the third embodiment of the present invention. The optical communication device 50f of this embodiment differs from the first embodiment in that it has a modulation section control section 250 that detects a power abnormality from the phase modulation section 320a and shuts down the high-output optical amplifier 40a and the signal generation section 210b. different.

The optical phase-modulated signal is a single-polarized binary phase-modulated signal. The optical communication device 50f has an optical transmitter 10f and a high-power optical amplifier 40a. The optical transmitter 10f has a digital signal processor 20f and an optical transmitter 30b. The digital signal processing section 20f has a signal generation section 210b, a signal interruption detection section 220, a clock data regenerator power supply control section 230b, a clock data regenerator current abnormality detection section 240, and a modulation section control section 250. Here, the digital signal processing unit 20f indicates an SRAM type FPGA or the like used on the ground. The optical transmission section 30 b has a transmission laser section 310 , a phase modulation section 320 a , a clock data regenerator 330 , a clock data regenerator current monitor section 340 , and a clock data regenerator power supply section 350 .

The input data D1 is converted into the main signal I1 by the signal generator 210b. The main signal I1 is input to the clock data regenerator 330, and waveform equalization of the main signal I1 is performed. The waveform-equalized main signal I1 is input to the phase modulating section 320a. A laser beam is output from the transmission laser unit 310 . On the other hand, the output laser light is input to the phase modulating section 320a. The phase modulating section 320a modulates the laser light based on the main signal I1 and outputs an optical phase modulated signal. The optical phase-modulated signal is input to the high-power optical amplifier 40 and is amplified by high-power light. The high-output optically amplified optical phase-modulated signal is output from the optical communication device 50f.

The current flowing through clock data regenerator 330 is monitored by clock data regenerator current monitor 340 . When a current abnormality occurs in the clock data regenerator 330, the clock data regenerator current abnormality detector 240 detects the current abnormality, and after transmitting a shutdown signal SD1 to the high-output optical amplifier 40 and the signal generator 210b, the clock data A current abnormality detection signal is transmitted to the regenerator power supply control section 230 . Upon receiving the shutdown signal SD1, the signal generator 210 stops generating the main signal I1. Note that the clock data regenerator current abnormality detection section 240 may also transmit the shutdown signal SD1 to the transmission laser section 310 to shut down the transmission laser section 310 .

On the other hand, when the main signal I1 input to the clock data regenerator 330 is interrupted, the signal interruption detector 220 detects the signal interruption, and after transmitting the shutdown signal SD1 to the high-output optical amplifier 40, the clock data A signal interruption detection signal is transmitted to the regenerator power supply control section 230b. Note that the signal interruption detection unit 220 may also transmit the shutdown signal SD1 to the signal generation unit 210b and the transmission laser unit 310 to shut them down. The clock data regenerator power supply control unit 230b transmits a shutdown signal SD2 to the clock data regenerator power supply unit 350 upon receiving the current abnormality detection signal or the signal interruption detection signal. The clock data regenerator power supply unit 350 stops supplying the power supply voltage to the clock data regenerator 330 upon receiving the shutdown signal SD2.

The modulation section control section 250 sets the bias voltage of the phase modulation section 320a and monitors the power of the phase modulation section 320a. Also, at the start of optical signal transmission, the modulation unit control unit 250 initializes the bias voltage. When a power abnormality occurs in the optical output of the phase modulation section 320a, after transmitting a shutdown signal SD1 to the high-output optical amplifier 40a and the signal generation section 210b, a power abnormality detection signal is transmitted to the clock data regenerator power supply control section 230b. . Here, the optical power abnormality of the optical output from the phase modulating section 320a is a state in which the optical power of the optical output from the phase modulating section 320a decreases, increases, or fluctuates by a predetermined amount or more. The phase modulating section 320a has, for example, a photodetector, monitors the optical power of the optical output during a period when the optical power does not change due to modulation, An optical power anomaly may be detected by detecting a decreasing or increasing or fluctuating state. The same applies to the phase modulating section of each embodiment below. Upon receiving the shutdown signal SD1, the signal generator 210b stops generating the main signal I1. The modulation section control section 250 may also transmit the shutdown signal SD1 to the transmission laser section 310 to shut it down.

Upon receiving the power abnormality detection signal, the clock data regenerator power supply control unit 230b transmits a shutdown signal SD2 to the clock data regenerator power supply unit 350. FIG. The clock data regenerator power supply unit 350 stops supplying the power supply voltage to the clock data regenerator 330 upon receiving the shutdown signal SD2.

FIG. 13 is a configuration diagram of the phase modulating section in FIG. The phase modulation section 320 a has an optical modulator 321 , a bias voltage control section 322 , an optical branch section 323 and a photoelectric conversion section 324 .

The laser light from the transmission laser section 310 is input to the optical modulator 321 together with the main signal I1 to generate an optical phase modulated signal. The optical phase-modulated signal is split by the optical splitter 323, and one is output from the phase modulator 320a. The other is converted into an electrical signal by the photoelectric conversion section 324 and input to the bias voltage control section 322 . At this time, the bias voltage control section 322 controls the bias voltage based on the electrical signal from the photoelectric conversion section 324 so that the optical phase modulation signal can be generated. Send power monitor information. Also, when an instruction to set the bias voltage is given from the modulation section control section 250 , the bias voltage value is set in the optical modulator 321 .

FIG. 14 is a configuration diagram of a modification of the phase modulating section in FIG. A phase modulating section 320b of this modified example has an optical modulator 321 and a bias voltage control section 322 . The laser light from the transmission laser section 310 is input to the optical modulator 321 together with the main signal I1 to generate an optical phase modulated signal. At this time, the bias voltage control unit 322 controls the bias voltage based on the electrical signal from the photoelectric conversion unit 324 inside the optical modulator 321 so that the optical phase modulation signal can be generated. , transmits the power monitor information of the phase modulation unit 320b. Also, when an instruction to set the bias voltage is given from the modulation section control section 250 , the bias voltage value is set in the optical modulator 321 .

The optical transmitter 30b may have an intensity modulator instead of the phase modulators 320a and 320b, and the intensity modulator may output an optical intensity modulated signal.

Further, the digital signal processing unit 20f has a clock generation unit that generates a clock signal, the optical transmission unit 30b is configured to have an intensity modulation unit after the phase modulation unit 320a or 320b, and the clock generation unit generates the clock signal. By inputting to the intensity modulating section, a configuration may be adopted in which an RZ (Return-to-zero) modulated signal is output. The transmission laser unit 310 may be configured to be shut down after receiving the shutdown signal SD1.

As for the operation of the high-output optical amplifier 40a, processing similar to that of the optical communication device 50 of the first embodiment is performed. The configuration of the high-output optical amplifier 40a is such that one control line for the shutdown signal SD1 from the modulation section control section 250 is added to the control line for the shutdown signal SD1 input to the excitation laser control section 420. FIG.

<Third Embodiment: System Operation>
FIG. 15A is a flow chart explaining the first optical transmission control method of the third embodiment. This flowchart is executed when an abnormality due to the influence of radiation occurs while the optical transmitter 10f inside the optical communication device 50f and the high-output optical amplifier 40a are operating normally.

In step S301, the clock data regenerator current monitoring unit 340 monitors the current of the clock data regenerator 330, the signal interruption detection unit 220 monitors the main signal I1 of the signal generation unit 210b, and the modulation unit control unit 250 performs phase modulation. Monitor the power of section 320a. In step S302, if the clock data regenerator current monitoring unit 340 detects an abnormality in the current of the clock data regenerator 330, the process proceeds to step S305. If no current abnormality is detected, the process proceeds to step S303. In step S303, if the modulation section control section 250 detects a power abnormality in the phase modulation section 320a, the process proceeds to step S305. If no power abnormality is detected, the process proceeds to step S304. In step S304, if the signal interruption detection unit 220 detects the signal interruption of the signal generation unit 210b, the process proceeds to step S305. If no signal interruption is detected, the process returns to step S301, the clock data regenerator current monitoring unit 340 monitors the current of the clock data regenerator 330, the signal interruption detection unit 220 monitors the main signal I1 of the signal generation unit 210b, The modulation section control section 250 monitors the power of the phase modulation section 320a.

In step S305, the clock data regenerator current abnormality detector 240, modulator controller 250, or signal interruption detector 220 transmits a shutdown signal SD1 to the high-output optical amplifier 40a, and the process proceeds to step S306 or step S307. In step S306, the excitation laser control unit 420 stops supplying voltage to the power supply unit 410 in the high-output optical amplifier 40a, shuts down the high-output optical amplifier 40a, and proceeds to step S308. In step S307, the excitation laser control unit 420 stops current supply to the excitation laser units 450a and 450b in the high-power optical amplifier 40a, shuts down the high-power optical amplifier 40, and proceeds to step S308.

In step S308, if no signal interruption is detected, the process proceeds to step S309, the clock data regenerator current abnormality detection unit 240 transmits a shutdown signal SD1 to the signal generation unit 210b, the main signal is stopped, and the process proceeds to step S310. move on. If signal interruption is detected, the process proceeds to step S310. In step S310, the clock data regenerator power control unit 230b stops power supply to the clock data regenerator 330, and the process proceeds to step S311. In step S311, the transmission laser unit 310 is shut down. This is the end of this flowchart.

Further, in step S307, the pumping laser control unit 420 may stop the current supply only to the pumping laser unit 450b necessary for the booster light amplification unit 470 to amplify the high-output light.

As described above, according to the third embodiment, detection of current abnormality in the clock data regenerator 330, detection of main signal interruption of the main signal from the clock data regenerator 330, and detection of power abnormality in the phase modulation section 320a are performed. , the high power optical amplifier 40a and the signal generator 210b are shut down. After that, the power supply to the clock data regenerator 330 is stopped. With this configuration, when an abnormality in the clock data regenerator 330 is detected, the high-output optical amplifier 40a is quickly shut down and the main signal is stopped. , the optical surge caused by the abnormality of the main signal caused by the radiation of the clock data regenerator 330 can be prevented, and the protection of the high output optical amplifier 40a can be realized. Moreover, since the high-output optical amplifier 40a and the signal generator 210b are shut down based on the detection of the power abnormality of the phase modulation section 320a, the main signal abnormality caused by the radiation of the clock data regenerator 330 can be detected more reliably.

In the above description of the optical transmission control method, the high-output optical amplifier 40a and the signal generator 210b are shut down, the power supply to the clock data regenerator 330 is stopped, and then the transmission laser unit 310 is shut down. The order is not limited.

FIG. 15B is a flowchart illustrating a modification of the first optical transmission control method of the third embodiment; This flowchart is executed when an abnormality due to the influence of radiation occurs while the optical transmitter 10f inside the optical communication device 50f and the high-output optical amplifier 40a are operating normally.

In step S321, the clock data regenerator current monitoring unit 340 monitors the current of the clock data regenerator 330, and the signal interruption detection unit 220 monitors the main signal I1 of the signal generation unit 210b. In step S322, if the clock data regenerator current anomaly detector 240 detects the current anomaly of the clock data regenerator 330, the process proceeds to step S325.

If no current abnormality is detected in step S322, the process proceeds to step S323. In step S323, if the modulation section control section 250 detects the power abnormality of the phase modulation section 320a, the process proceeds to step S325. If no power abnormality is detected, the process proceeds to step S324. In step S324, if the signal interruption detection unit 220 detects the signal interruption of the signal generation unit 210, the process proceeds to step S325. If no signal interruption is detected in step S324, the process returns to step S321 to monitor the current of the clock data regenerator 330, the main signal I1 of the signal generator 210, and the power of the phase modulator 320a.

In step S325, the clock data regenerator current abnormality detection unit 240, the modulation unit control unit 250, or the signal interruption detection unit 220 transmits a shutdown signal SD1 to the transmission laser unit 310 to shut down the transmission laser unit 310, and the process proceeds to step S326. move on.

If no signal interruption is detected in step S326, the process proceeds to step S327, the clock data regenerator current abnormality detector 240 transmits the shutdown signal SD1 to the signal generator 210, and the process proceeds to step S328. If signal disconnection is detected in step S326, the process proceeds to step S328. In step S328, the clock data regenerator power control unit 230b stops power supply to the clock data regenerator 330, and the process proceeds to step S329.

In step S329, the clock data regenerator current abnormality detector 240, modulator controller 250, or signal interruption detector 220 transmits a shutdown signal SD1 to the high-output optical amplifier 40, and the process proceeds to step S330 or step S331. In step S330, the excitation laser control section 420 stops supplying voltage to the power supply section 410 in the high-power optical amplifier 40a to shut down the high-power optical amplifier 40a. In step S331, the pumping laser control unit 420 stops current supply to the pumping laser units 450a and 450b in the high-power optical amplifier 40a and shuts down the high-power optical amplifier 40a. This is the end of this flowchart.

In this way, even if the transmission laser unit 310 is first shut down, the power supply to the clock data regenerator 330 is stopped, and then the high-output optical amplifier 40a and the signal generation unit 210b are shut down, optical surges can be prevented and high output can be achieved. Protection of optical amplifiers and devices affected by the output of high-power optical amplifiers can be achieved. Examples of devices that are affected by the output of a high-power optical amplifier include an optical acquisition and tracking device that constitutes an optical communication device on the transmitting side, an optical acquisition and tracking device that constitutes an optical communication device on the receiving side, a low-noise optical amplifier, and an optical amplifier. receiver, etc.

Next, the second optical transmission control method of the third embodiment will be explained. FIG. 16 is a flow chart for explaining the second optical transmission control method of the third embodiment. This flowchart is executed when an abnormality due to the influence of radiation occurs while the optical transmitter 10f inside the optical communication device 50f and the high-output optical amplifier 40a are operating normally.

In step S341, the clock data regenerator current monitoring unit 340 monitors the current of the clock data regenerator 330, the signal interruption detection unit 220 monitors the main signal I1 of the signal generation unit 210b, and the modulation unit control unit 250 performs phase modulation. Monitor the power of section 320a. In step S342, if the clock data regenerator current monitoring unit 340 detects an abnormality in the current of the clock data regenerator 330, the process proceeds to step S345. If no current abnormality is detected, the process proceeds to step S343. In step S343, if the modulation section control section 250 detects the power abnormality of the phase modulation section 320, the process proceeds to step S345. If no power abnormality is detected, the process proceeds to step S344. In step S344, if the signal interruption detection unit 220 detects the signal interruption of the signal generation unit 210, the process proceeds to step S345. If no signal interruption is detected, the process returns to step S341, the clock data regenerator current monitoring unit 340 monitors the current of the clock data regenerator 330, the signal interruption detection unit 220 monitors the main signal I1 of the signal generation unit 210b, The modulation section control section 250 monitors the power of the phase modulation section 320a.

In step S345, the clock data regenerator current abnormality detection unit 240, the modulation unit control unit 250, or the signal interruption detection unit 220 transmits the shutdown signal SD1 to the signal generation unit, the main signal I1 is stopped, and the process proceeds to step S346. . In step S<b>346 , the clock data regenerator power control unit 230 b stops power supply to the clock data regenerator 330 . In step S347, the modulation section control section 250 changes the bias voltage at a slow start, and the power of the phase modulation section 320a is controlled to increase, and the process proceeds to step S348. At this time, the modulating unit control unit 250 controls the bias voltage value so that the power of the phase modulating unit 320a becomes half or more of the maximum power value. In step S348, the clock data regenerator current abnormality detection unit 240, the modulation unit control unit 250, or the signal interruption detection unit 220 transmits the shutdown signal SD1 to the high-output optical amplifier 40a, and the process proceeds to step S349. In step S349, the excitation laser control unit 420 changes the current values of the excitation laser units 450a and 450b in the high-power optical amplifier 40 at a slow start to stop the current supply, shut down the high-power optical amplifier 40a, and step Proceed to S350. At step S 350 , the clock data regenerator current abnormality detector 240 , the modulator controller 250 , or the signal interruption detector 220 shuts down the transmission laser section 310 . This is the end of this flowchart.

As described above, according to the second optical transmission control method of the third embodiment, at least one of the current abnormality of the clock data regenerator 330, the main signal interruption of the main signal, and the power abnormality of the phase modulation section 320a is detected. First, the signal generator 210b is shut down, and then the power supply to the clock data regenerator 330 is stopped. Then, the current values of the excitation laser sections 450a and 450b in the high-power optical amplifier 40 are changed at slow start, the current supply is stopped, and the high-power optical amplifier 40a is shut down. With such a control method, normal shutdown of the high-output optical amplifier 40a can be performed while light is being input to the high-output optical amplifier 40a, so that safer control becomes possible.

In step S349, the excitation laser control section 420 may stop current supply only to the excitation laser section 450b required for high-output optical amplification of the booster optical amplification section 470. FIG.

FIG. 17A is a diagram showing the principle of generating an optical phase-modulated signal output from a phase modulating section. A main signal input to the optical modulator 321 passes through a modulation curve, and an optical phase modulated signal is generated as an optical output. At this time, the bias point is located at the minimum point of the modulation curve. FIG. 17B is a diagram showing the control operation of step S347 in FIG. When the main signal stops, the bias point is located at the minimum point, so the light output is zero. After that, the bias point moves from the minimum point to the maximum point by slowly starting to change the bias voltage value in the direction of increasing power. As a result, since the optical output increases slowly, the influence of optical surge caused by a sudden increase in optical power is eliminated.

Next, the third optical transmission control method of the third embodiment will be explained. FIG. 18 is a flow chart for explaining the third optical transmission control method of the third embodiment. This flowchart is executed when an abnormality due to the influence of radiation occurs while the optical transmitter 10f inside the optical communication device 50f and the high-output optical amplifier 40a are operating normally. Also, it is assumed that the optical transmission section 30b has a configuration having an intensity modulation section instead of a phase modulation section.

In step S361, the clock data regenerator current monitoring unit 340 monitors the current of the clock data regenerator 330, the signal interruption detection unit 220 monitors the main signal I1 of the signal generation unit 210b, and the modulation unit control unit 250 performs intensity modulation. monitor the power of the In step S362, if the clock data regenerator current monitoring unit 340 detects an abnormality in the current of the clock data regenerator 330, the process proceeds to step S365. If no current abnormality is detected, the process proceeds to step S363. In step S363, if the modulation unit control unit 250 detects power abnormality in the intensity modulation unit, the process proceeds to step S365. If no power abnormality is detected, the process proceeds to step S364. In step S364, if the signal interruption detection unit 220 detects the signal interruption of the signal generation unit 210, the process proceeds to step S365. If no signal interruption is detected, the process returns to step S361, the clock data regenerator current monitoring unit 340 monitors the current of the clock data regenerator 330, the signal interruption detection unit 220 monitors the main signal I1 of the signal generation unit 210b, A modulator controller 250 monitors the power of the intensity modulator.

In step S365, the clock data regenerator current abnormality detection unit 240, the modulation unit control unit 250, or the signal interruption detection unit 220 transmits the shutdown signal SD1 to the signal generation unit, the main signal I1 is stopped, and the process proceeds to step S366. . In step S<b>366 , the clock data regenerator power control unit 230 b stops power supply to the clock data regenerator 330 . In step S367, the signal interruption detection unit 220 controls the bias voltage value to be maintained at the same value as before the main signal is stopped, so that the power of the intensity modulation unit can be maintained at the same power value as before the main signal is stopped. The process proceeds to step S368. In step S368, the clock data regenerator current abnormality detection unit 240, the modulation unit control unit 250, or the signal interruption detection unit 220 transmits the shutdown signal SD1 to the high-output optical amplifier 40a, and the process proceeds to step S369. In step S369, the excitation laser control unit 420 changes the current values of the excitation laser units 450a and 450b in the high-power optical amplifier 40a at a slow start to stop the current supply, shut down the high-power optical amplifier 40a, and step Proceed to S370. In step S370, the clock data regenerator current abnormality detection unit 240, the modulation unit control unit 250, or the signal interruption detection unit 220 shuts down the transmission laser unit 310. FIG. This is the end of this flowchart.

In addition, in step S369, the excitation laser control section 420 may stop the current supply only to the excitation laser section 450b required for the booster optical amplification section 470 to amplify high-output light.

FIG. 19A is a diagram showing the principle of generating an optical intensity modulated signal output from an intensity modulating section. A main signal input to the optical modulator 321 passes through a modulation curve, and an optical intensity modulated signal is generated as an optical output. At this time, the bias point is located at the midpoint of the modulation curve. FIG. 19B is a diagram showing the control operation of step S347 in FIG. When the main signal stops, the bias point is positioned at the middle point, so the optical output has the same value as before the main signal. After that, control is performed so that the bias voltage value is maintained at the same value as before the main signal so that the optical output becomes the same value as before the main signal.

As described above, according to the third optical transmission control method of the third embodiment, detection of an abnormality in the current of the clock data regenerator 330, detection of interruption of the main signal, and detection of an abnormality in the power of the phase modulating section 320a are performed. Based on at least one, the signal generator 210b is shut down first, and the clock data regenerator 330 is powered down after that. Then, the bias voltage value is held at the same value as before the main signal is stopped, and the high-output optical amplifier 40a is shut down. With such a control method, the bias point is maintained at the intermediate point, so that the optical output does not change, so the influence of an optical surge due to a sudden increase in optical power is eliminated.

<Modified Example of Third Embodiment: Optical Communication Devices 50g and 50h>
A modification of the optical communication device according to the third embodiment of the present invention will be described. FIG. 20 is a configuration diagram of an optical communication device 50g according to the first modification of the third embodiment. The optical transmitter 10g has a digital signal processing section 20g, a radiation-resistant digital signal processing section 21d, and an optical transmission section 30b. Here, the radiation-tolerant digital signal processing unit 21d is an FPGA or the like that has a track record of being mounted on a satellite and has radiation resistance. FIG. 20 shows a case where the clock data regenerator power supply controller 230b is included in the radiation-tolerant digital signal processor 21d. The operation processing of the optical communication device 50g is the same as that of the third embodiment.

FIG. 21 is a configuration diagram of an optical communication device 50h according to a second modification of the third embodiment. The optical transmitter 10h has a digital signal processor 20h, a radiation-resistant digital signal processor 21e, and an optical transmitter 30b. FIG. 21 shows that a signal interruption detection section 220, a clock data regenerator power supply control section 230b, a clock data regenerator current abnormality detection section 240, and a modulation section control section 250 are included in a radiation-resistant digital signal processing section 21e. indicates the case. Here, the radiation-tolerant digital signal processing unit 21e indicates an FPGA or the like that has a track record of being mounted on a satellite and has radiation resistance. The operation processing of the optical communication device 50h is the same as that of the third embodiment.

These modified examples provide the same effects as the third embodiment, and use of the radiation-resistant digital signal processing unit enables reliable detection of main signal abnormalities due to radiation.

<Fourth Embodiment: Optical Communication Device 50i>
An optical communication device according to a fourth embodiment of the present invention will be described. FIG. 22 is a configuration diagram of an optical communication device 50i according to the fourth embodiment of the present invention. The optical phase-modulated signal of this embodiment is a single-polarized quaternary phase-modulated signal, as in the second embodiment. However, the IQ modulation unit 360a corresponding to the phase modulation unit in the second embodiment is a plurality of optical modulators that perform phase modulation based on each of the plurality of waveform-equalized main signals and output optical phase-modulated signals. 361a and 361b. The optical communication device 50i according to this embodiment also has a modulation section control section 250a that detects power anomalies from the plurality of optical modulators 361a and 361b and shuts down the high-output optical amplifier 40a and the signal generation section 210c. This embodiment differs from the second embodiment in these respects.

The optical communication device 50i has an optical transmitter 10i and a high power optical amplifier 40a. The optical transmitter 10i has a digital signal processor 20i and an optical transmitter 30c. The digital signal processing section 20i has a signal generation section 210c, a signal interruption detection section 220a, a clock data regenerator power supply control section 230c, a clock data regenerator current abnormality detection section 240a, and a modulation section control section 250a. Here, the digital signal processing unit 20i indicates an SRAM type FPGA or the like used on the ground. The optical transmission section 30c includes a transmission laser section 310, an IQ modulation section 360a, a clock data regenerator 331 having clock data regenerative circuits 330a and 330b, a clock data regenerator current monitoring section 340a, and a clock data regenerator power supply. and a portion 350a.

The input data D1 and D2 are converted into main signals I1 and I2 in the signal generator 210c. The main signals I1 and I2 are input to clock data recovery circuits 330a and 330b, and the waveforms of the main signals I1 and I2 are equalized. The waveform-equalized main signal is input to the IQ modulation section 360a. A laser beam is output from the transmission laser unit 310 . On the other hand, the output laser light is input to the IQ modulation section 360a. The IQ modulation section 360a modulates the laser light based on the main signals I1 and I2, and outputs an optical phase modulated signal. The optical phase-modulated signal is input to the high-power optical amplifier 40a and is amplified by high-power light. The high-output optically amplified optical phase-modulated signal is output from the optical communication device 50i.

The currents flowing through the clock data recovery circuits 330a and 330b are monitored by the clock data recovery current monitor 340a. When a current abnormality occurs in the clock data recovery circuit 330a or 330b, the clock data recovery device current abnormality detection section 240a detects the current abnormality, and after transmitting a shutdown signal SD1 to the high-output optical amplifier 40a and the signal generation section 210c, A current abnormality detection signal is transmitted to the clock data regenerator power control unit 230c. Upon receiving the shutdown signal SD1, the signal generator 210c stops generating the main signals I1 and I2. The clock data regenerator current abnormality detection section 240a may also transmit the shutdown signal SD1 to the transmission laser section 310 to shut down the transmission laser section 310. FIG.

On the other hand, when the main signal I1 input to the clock data recovery circuit 330a or the main signal I2 input to the clock data recovery circuit 330b is disconnected, the signal disconnection detector 220a detects the signal disconnection and outputs a high signal. After transmitting the shutdown signal SD1 to the optical amplifier 40a, a signal disconnection detection signal is transmitted to the clock data regenerator power control unit 230c. Note that the signal interruption detection unit 220a may also transmit the shutdown signal SD1 to the signal generation unit 210c and the transmission laser unit 310 to shut them down. When the clock data regenerator power supply control unit 230c receives the current abnormality detection signal or the signal interruption detection signal, it transmits a shutdown signal SD2 to the clock data regenerator power supply unit 350a. When the clock data regenerator power supply unit 350a receives the shutdown signal SD2, it stops supplying the power supply voltage to the clock data regenerator circuits 330a and 330b.

The modulation section control section 250a sets the bias voltage of the IQ modulation section 360a and monitors the power of the IQ modulation section 360a. Also, at the start of optical signal transmission, the modulation unit control unit 250 initializes the bias voltage. When an abnormality occurs in the optical output power of the IQ modulation unit 360a, the modulation unit control unit 250a transmits a shutdown signal SD1 to the high-output optical amplifier 40a and the signal generation unit 210c, and then supplies power to the clock data regenerator power supply control unit 230c. Send an anomaly detection signal. Upon receiving the shutdown signal SD1, the signal generator 210c stops generating the main signals I1 and I2. The modulation unit control unit 250a may also transmit the shutdown signal SD1 to the transmission laser unit 310 to shut it down. Upon receiving the power abnormality detection signal, the clock data regenerator power supply control unit 230c transmits a shutdown signal SD2 to the clock data regenerator power supply unit 350a. When the clock data regenerator power supply unit 350a receives the shutdown signal SD2, it stops supplying the power supply voltage to the clock data regenerator circuits 330a and 330b.

23 is a configuration diagram of the IQ modulation section of FIG. 22. FIG. The IQ modulation section 360a includes optical modulators 361a and 361b, a bias voltage control section 362, optical branching sections 363a and 363b and 363c and 363d, photoelectric conversion sections 364a and 364b and 364c and 364d, and an optical phase adjustment section 365. and

The laser light from the transmission laser unit 310 is branched into two, and input to the optical modulators 361a and 361b along with the main signals I1 and I2, respectively, to generate optical signals. Optical signals from optical modulators 361a and 361b are branched by optical branching units 363a and 363b. One output from the optical branching units 363a and 363b is converted into an electric signal by the photoelectric conversion unit 364a and the photoelectric conversion unit 364b, and is input to the bias voltage control unit 362. FIG. The other output of the optical splitter 363b is input to the optical phase adjuster 365, where it is phase-shifted by π/2.

The optical signal phase-shifted by the optical phase adjuster 365 is input to the optical splitter 363c. One output from the optical splitter 363 c is converted into an electric signal by the photoelectric converter 364 c and input to the bias voltage controller 362 . The other output of the optical splitter 363a is combined with the other output of the optical splitter 363c to generate an optical phase modulated signal.

The optical phase modulated signal is split by the optical splitter 363d. One output of the optical splitter 363 d is converted into an electric signal by the photoelectric converter 364 d and input to the bias voltage controller 362 . The other output of the optical splitter 363d is transmitted as an optical phase modulated signal from the IQ modulator 360a.

The bias voltage control unit 362 controls the bias voltage based on the electrical signals from the photoelectric conversion units 364a, 364b, 364c, and 364d so as to generate an optical phase modulation signal, and the modulation unit control unit 250a performs IQ modulation. The power monitor information of the section 360a is transmitted. Also, when a bias voltage setting instruction is issued from the modulating unit control unit 250 a , the bias voltage value is set in the optical modulators 361 a and 361 b and the optical phase adjusting unit 365 .

FIG. 24 is a configuration diagram of a modified example of the IQ modulation section in FIG. The IQ modulation section 360b of this modified example has optical modulators 361c and 361d, a bias voltage control section 362a, an optical branching section 363e, a photoelectric conversion section 364d, and an optical phase adjustment section 365a.

The laser light from the transmission laser unit 310 is branched into two and input to the optical modulators 361c and 361d together with the main signals I1 and I2 to generate optical signals. The optical signal from the optical modulator 361d is input to the optical phase adjuster 365a and phase-shifted by π/2. The optical signal phase-shifted by the optical phase adjuster 365a is combined with the optical signal from the optical modulator 361c to generate an optical phase-modulated signal.

The optical phase modulated signal is split by the optical splitter 363e. One output of the optical splitter 363e is converted into an electric signal by the photoelectric converter 364d and input to the bias voltage controller 362a. The other output of the optical splitter 363 is transmitted as an optical phase modulated signal from the IQ modulator 360b.

The bias voltage control unit 362a is connected to the optical modulators 361c and 361d and the electrical signals from the photoelectric conversion unit inside the optical phase adjustment unit 365a, and to the optical branch unit 363e so as to generate an optical phase modulation signal. The bias voltage is controlled based on the electric signal from the photoelectric conversion unit 364d. Then, the bias voltage control section 362a transmits the power monitor information of the IQ modulation section 360b to the modulation section control section 250a. Further, when an instruction to set the bias voltage is given from the modulation section control section 250a, the bias voltage value is set in the optical modulators 361c and 361d and the optical phase adjustment section 365a.

The digital signal processing unit 20i of this embodiment has a clock generation unit that generates a clock signal, and the optical transmission unit 30c is configured to have an intensity modulation unit after the IQ modulation units 360a and 360b. , a clock signal may be input to the intensity modulation unit to output an RZ (Return-to-zero) modulated signal. The transmission laser unit 310 may be configured to be shut down after receiving the shutdown signal SD1.

The operation of the high-power optical amplifier 40a of this embodiment is similar to that of the high-power optical amplifier 40a of the optical communication device 50f of the third embodiment.

Although an example has been given for a QPSK signal, it is also applicable to optical signals of M-PSK in which M is four or more, M-QAM (Quadrature Amplitude Modulation), and M-APSK (Amplitude Phase Shift Keying).

<Fourth Embodiment: System Operation>
FIG. 25 is a flow chart for explaining the first optical transmission control method of the fourth embodiment. This flowchart is executed when an abnormality due to the influence of radiation occurs while the optical transmitter 10i inside the optical communication device 50i and the high-output optical amplifier 40a are operating normally.

In step S401, the clock data regenerator current monitoring unit 340a monitors the currents of the clock data regenerating circuits 330a and 330b, the signal interruption detection unit 220a monitors the main signals I1 and I2 of the signal generation unit 210c, and the modulation unit control unit 250a monitors the power of the IQ modulator 360a. In step S402, if the clock data regenerator current abnormality detector 240a detects a current abnormality in the clock data regenerator circuit 330a or 330b, the process proceeds to step S405. If no current abnormality is detected, the process proceeds to step S403. In step S403, if the modulation section control section 250a detects a power abnormality in the IQ modulation section 360a, the process proceeds to step S405. If no power abnormality is detected, the process proceeds to step S404. In step S404, if the signal interruption detection unit 220a detects the signal interruption of the signal generation unit 210c, the process proceeds to step S405. If no signal interruption is detected, the process returns to step S401, the clock data regenerator current monitoring unit 340a monitors the currents of the clock data reproduction circuits 330a and 330b, and the signal interruption detection unit 220a monitors the main signals I1 and I2 of the signal generation unit 210c. , and the modulation section control section 250a monitors the power of the IQ modulation section 360a.

In step S405, the clock data regenerator current abnormality detection unit 240a, modulation unit control unit 250a, or signal interruption detection unit 220a transmits a shutdown signal SD1 to the high-output optical amplifier 40a, and the process proceeds to step S406 or step S407. In step S406, the excitation laser control unit 420 stops supplying voltage to the power supply unit 410 in the high-output optical amplifier 40a, shuts down the high-output optical amplifier 40a, and proceeds to step S408. In step S407, the excitation laser control unit 420 stops current supply to the excitation laser units 450a and 450b in the high-power optical amplifier 40a, shuts down the high-power optical amplifier 40a, and proceeds to step S408.

In step S408, if no signal interruption is detected, the process proceeds to step S409, and the clock data regenerator current abnormality detection unit 240a, modulation unit control unit 250a, or signal interruption detection unit 220a sends a shutdown signal to the signal generation unit 210c. SD1 is transmitted, the main signal is stopped, and the process proceeds to S410. If signal interruption is detected, the process proceeds to step S410. In step S410, the clock data regenerator power control unit 230c stops power supply to the clock data regenerators 330a and 330b, and the process proceeds to step S411. In step S411, the clock data regenerator current abnormality detection unit 240a, the modulation unit control unit 250a, or the signal interruption detection unit 220a shuts down the transmission laser unit 310. FIG. This is the end of this flowchart.

As described above, according to the fourth embodiment, detection of current abnormality in any one of the plurality of clock data recovery circuits 330a and 330b, detection of main signal interruption in any of the plurality of main signals, and power control of the IQ modulation section 360a High power optical amplifier 40a and signal generator 210c are shut down based on at least one of the detection of anomalies. Power supply to the clock data recovery circuits 330a and 330b is then stopped. With this configuration, when an abnormality in the clock data recovery circuits 330a and 330b is detected, the high-output optical amplifier 40a is shut down and the main signal is stopped immediately. Therefore, according to the fourth embodiment, similarly to the first, second and third embodiments, it is possible to prevent the optical surge caused by the main signal abnormality due to the radiation of the clock data recovery circuits 330a and 330b, and the high output optical amplifier. 40a protection can be realized. Since the high-output optical amplifier 40a and the signal generator 210c are shut down based on the detection of the power abnormality of the IQ modulation section 360a, it is possible to more reliably detect the radiation-induced main signal abnormality of the clock data recovery circuits 330a and 330b.

In step S407, the excitation laser control section 420 may stop the current supply only to the excitation laser section 450b necessary for the booster optical amplification section 470 to amplify high-output light.

In the above description of the optical transmission control method, the high-output optical amplifier 40a and the signal generation section 210c are shut down, the power supply to the clock data recovery circuits 330a and 330b is stopped, and then the transmission laser section 310 is shut down. , but not limited to this order.

FIG. 25B is a flow chart explaining a modification of the first optical transmission control method of the fourth embodiment. This flowchart is executed when an abnormality due to the influence of radiation occurs while the optical transmitter 10i inside the optical communication device 50i and the high-output optical amplifier 40a are operating normally.

In step S421, the clock data regenerator current monitoring unit 340a monitors the currents of the clock data regenerating circuits 330a and 330b, the signal interruption detection unit 220a monitors the main signals I1 and I2 of the signal generation unit 210c, and the modulation unit control unit 250a monitors the power of the IQ modulator 360a.

In step S422, if the clock data regenerator current abnormality detector 240a detects a current abnormality in the clock data regenerator circuit 330a or 330b, the process proceeds to step S425. If no current abnormality is detected, the process proceeds to step S423. In step S423, if the modulation section control section 250a detects the power abnormality of the IQ modulation section 360a, the process proceeds to step S425. If no power abnormality is detected, the process proceeds to step S424. In step S424, if the signal interruption detection unit 220a detects the signal interruption of the signal generation unit 210c, the process proceeds to step S405. If no signal interruption is detected, the process returns to step S421, the clock data regenerator current monitoring unit 340a monitors the currents of the clock data reproduction circuits 330a and 330b, and the signal interruption detection unit 220a detects the main signals I1 and I2 of the signal generation unit 210c. , and the modulation section control section 250a monitors the power of the IQ modulation section 360a.

In step S425, the clock data regenerator current abnormality detection unit 240a, the modulation unit control unit 250a, or the signal interruption detection unit 220a transmits a shutdown signal SD1 to the transmission laser unit 310 to shut down the transmission laser unit 310, and the process proceeds to step S426. move on.

If no signal interruption is detected in step S426, the process proceeds to step S427, where the clock data regenerator current abnormality detection unit 240a, the modulation unit control unit 250a, or the signal interruption detection unit 220a sends the shutdown signal SD1 to the signal generation unit 210c. is transmitted, and the process proceeds to step S428. If signal disconnection is detected in step S426, the process proceeds to step S428. In step S428, the clock data regenerator power control unit 230c stops power supply to the clock data regenerator circuits 330a and 330b, and the process proceeds to step S429.

In step S429, the clock data regenerator current abnormality detection unit 240, the modulation unit control unit 250, or the signal interruption detection unit 220 transmits the shutdown signal SD1 to the high-output optical amplifier 40, and the process proceeds to step S430 or step S431. In step S430, the excitation laser control section 420 stops supplying voltage to the power supply section 410 in the high-power optical amplifier 40a to shut down the high-power optical amplifier 40a. In step S431, the pumping laser control unit 420 stops current supply to the pumping laser units 450a and 450b in the high-power optical amplifier 40a and shuts down the high-power optical amplifier 40a. This is the end of this flowchart.

Thus, even if the transmission laser unit 310 is first shut down, the power supply to the clock data recovery circuits 330a and 330b is stopped, and then the high-output optical amplifier 40a and the signal generation unit 210c are shut down, optical surges can be prevented. A high power optical amplifier and protection of devices affected by the output of the high power optical amplifier can be achieved. Examples of devices that are affected by the output of a high-power optical amplifier include an optical acquisition and tracking device that constitutes an optical communication device on the transmitting side, an optical acquisition and tracking device that constitutes an optical communication device on the receiving side, a low-noise optical amplifier, and an optical amplifier. receiver, etc.

Next, the second optical transmission control method of the fourth embodiment will be explained. FIG. 26 is a flow chart for explaining the second optical transmission control method of the fourth embodiment. This flowchart is executed when an abnormality due to the influence of radiation occurs while the optical transmitter 10i inside the optical communication device 50i and the high-output optical amplifier 40a are operating normally.

In step S441, the clock data regenerator current monitoring unit 340a monitors the currents of the clock data regenerating circuits 330a and 330b, the signal interruption detection unit 220a monitors the main signals I1 and I2 of the signal generation unit 210c, and the modulation unit control unit 250a monitors the power of the IQ modulator 360a. In step S442, if the clock data regenerator current abnormality detection unit 240a detects a current abnormality in the clock data regenerating circuits 330a and 330b, the process proceeds to step S445. If no current abnormality is detected, the process proceeds to step S443. In step S423, if the modulation section control section 250a detects the power abnormality of the IQ modulation section 360a, the process proceeds to step S445. If no power abnormality is detected, the process proceeds to step S444. In step S444, if the signal interruption detection unit 220a detects the signal interruption of the signal generation unit 210c, the process proceeds to step S445. If no signal interruption is detected, the process returns to step S441, the clock data regenerator current monitoring unit 340a monitors the currents of the clock data reproduction circuits 330a and 330b, and the signal interruption detection unit 220a detects the main signals I1 and I2 of the signal generation unit 210c. , and the modulation section control section 250a monitors the power of the IQ modulation section 360a.

In step S445, the clock data regenerator current abnormality detection unit 240a, the modulation unit control unit 250a, or the signal interruption detection unit 220a transmits the shutdown signal SD1 to the signal generation unit 210c, the main signal I1 is stopped, and the process proceeds to step S426. move on. In step S426, the clock data regenerator power control unit 230c stops the power supply to the clock data regenerators 330a and 330b. In step S427, the modulation unit control unit 250a changes the bias voltage values of the optical modulators 361a and 361b and the optical phase adjustment unit 365 at a slow start to increase the power of the IQ modulation unit 360a. move on. At this time, the modulating unit control unit 250a controls the bias voltage value so that the power of the IQ modulating unit 360a becomes half or more of the maximum power value. In step S428, the clock data regenerator current abnormality detector 240a transmits the shutdown signal SD1 to the high-power optical amplifier 40a, and the process proceeds to step S429. In step S429, the excitation laser control unit 420 changes the current values of the excitation laser units 450a and 450b in the high-output optical amplifier 40a at a slow start to stop the current supply, shut down the high-output optical amplifier 40a, and step Proceed to S430. In step S430, the clock data regenerator current abnormality detection unit 240a, the modulation unit control unit 250a, or the signal interruption detection unit 220a shuts down the transmission laser unit 310. FIG. This is the end of this flowchart.

As described above, according to the second optical transmission control method of the fourth embodiment, detection of current abnormality in any one of the clock data recovery circuits, detection of loss of any one of a plurality of main signals, The signal generator is shut down based on at least one of the detection of the power abnormality in any one of (1) to (1), and then the power supply to the clock data recovery circuit is stopped. Then, the current values of the excitation laser sections 450a and 450b in the high-power optical amplifier 40a are changed at a slow start, the current supply is stopped, and the high-power optical amplifier 40a is shut down. With such a control method, according to this flow chart, normal shutdown of the high-output optical amplifier 40a can be performed while light is being input to the high-output optical amplifier 40a, so safer control becomes possible.

In step S449, the excitation laser control section 420 may stop current supply only to the excitation laser section 450b required for high-output optical amplification of the booster optical amplification section 470. FIG.

<Modified Example of the Fourth Embodiment: Optical Communication Devices 50j and 50k>
An optical communication device according to a modification of the fourth embodiment of the present invention will be described. FIG. 27 is a configuration diagram of an optical communication device 50j according to the first modification of the fourth embodiment. The optical transmitter 10j has a digital signal processor 20j, a radiation-resistant digital signal processor 21f, and an optical transmitter 30c. Here, the radiation-tolerant digital signal processing unit 21f indicates a radiation-tolerant FPGA or the like that has a track record of being mounted on a satellite. FIG. 27 shows a case where the clock data regenerator power supply controller 230c is included in the radiation-tolerant digital signal processor 21f. The operation processing of the optical communication device 50j is the same as that of the fourth embodiment.

FIG. 28 is a configuration diagram of an optical communication device 50k according to the second modification of the fourth embodiment. The optical transmitter 10k has a digital signal processing section 20k, a radiation-resistant digital signal processing section 21g, and an optical transmission section 30c. Here, the radiation-tolerant digital signal processing unit 21g is an FPGA or the like that has a track record of being mounted on a satellite and has radiation resistance. FIG. 28 shows the case where the signal interruption detection section 220a, the clock data regenerator power supply control section 230c, the clock data regenerator current abnormality detection section 240a, and the modulation section control section 250a are included in the radiation-resistant digital signal processing section 21g. is shown. The operation processing of the optical communication device 50k is the same as that of the fourth embodiment.

These modified examples provide the same effect as the fourth embodiment, and use of the radiation-resistant digital signal processing unit makes it possible to reliably detect main signal abnormalities caused by radiation.
<Appendix>
Some or all of the above embodiments may also be described as the following appendices. An outline of the optical communication device and the like according to the present invention will be described below. However, the present invention is not limited to the following configurations.
(Appendix 1)
a signal generator that generates a main signal;
a clock data regenerator that equalizes the waveform of the main signal;
a transmission laser unit that outputs laser light;
a phase modulation unit that phase-modulates the laser light based on the waveform-equalized main signal and outputs an optical phase-modulated signal;
a high-power optical amplifier that amplifies the optical phase-modulated signal with high-power light;
a clock data regenerator current anomaly detector for detecting a current anomaly of the clock data regenerator and shutting down the high-output optical amplifier, the signal generator, and the transmission laser;
a signal interruption detection unit that detects a main signal interruption of the main signal from the clock data regenerator and shuts down the high-output optical amplifier and the signal generation unit;
a clock data regenerator power control unit that stops power supply to the clock data regenerator after shutting down the high-output optical amplifier and the signal generation unit;
An optical communication device having
(Appendix 2)
The signal generator generates a plurality of main signals,
The clock data regenerator has a plurality of clock data regenerating circuits for waveform equalization of the plurality of main signals,
the clock data regenerator current anomaly detector detects a current anomaly of the plurality of clock data regenerator circuits and shuts down the high-power optical amplifier and the signal generator;
The signal loss detection unit detects a main signal loss of the plurality of main signals and shuts down the high-power optical amplifier and the signal generation unit.
The optical communication device according to appendix 1.
(Appendix 3)
2. The optical communication device according to claim 1, further comprising a first modulation section control section that detects power abnormality from the phase modulation section and shuts down the high-output optical amplifier and the signal generation section.
(Appendix 4)
The phase modulation unit includes a plurality of optical modulators that perform phase modulation based on each of the plurality of waveform-equalized main signals and output optical phase-modulated signals,
3. The optical communication device according to claim 2, further comprising a second modulator controller that detects power anomalies from the plurality of optical modulators and shuts down the high-output optical amplifier and the signal generator.
(Appendix 5)
It has a radiation-resistant digital signal processor,
wherein the clock data regenerator power control unit is provided in the radiation-tolerant digital signal processing unit;
5. The optical communication device according to any one of Appendices 1 to 4.
(Appendix 6)
It has a radiation-resistant digital signal processor,
The signal interruption detection section, the clock data regenerator current anomaly detection section, and the clock data regenerator power supply control section are provided in the radiation-tolerant digital signal processing section.
5. The optical communication device according to any one of Appendices 1 to 4.
(Appendix 7)
An optical transmitter that outputs an optical phase-modulated signal to a high-power optical amplifier,
a signal generator that generates a main signal;
a clock data regenerator that equalizes the waveform of the main signal;
a transmission laser unit that outputs laser light;
a phase modulation unit that phase-modulates the laser light based on the waveform-equalized main signal and outputs the optical phase-modulated signal;
a clock data regenerator current anomaly detector for detecting a current anomaly of the clock data regenerator and shutting down the high-power optical amplifier and the signal generator;
a signal interruption detection unit that detects a main signal interruption of the main signal from the clock data regenerator and shuts down the high-output optical amplifier and the signal generation unit;
a clock data regenerator power control unit that stops power supply to the clock data regenerator after shutting down the high-output optical amplifier and the signal generation unit;
an optical transmitter having a
(Appendix 8)
The signal generator generates a plurality of main signals,
The clock data regenerator has a plurality of clock data regenerating circuits for waveform equalization of the plurality of main signals,
wherein the clock data regenerator current abnormality detection unit transmits the shutdown signal when detecting a current abnormality in the plurality of clock data regenerator circuits;
The signal loss detection unit transmits the shutdown signal when detecting a main signal loss of the plurality of main signals.
8. The optical transmitter according to appendix 7.
(Appendix 9)
8. The optical transmitter according to claim 7, further comprising a first modulating section control section that transmits the shutdown signal when a power abnormality is detected from the phase modulating section.
(Appendix 10)
The phase modulation unit includes a plurality of optical modulators that perform phase modulation based on each of the plurality of waveform-equalized main signals and output optical phase-modulated signals,
8. The optical transmitter according to appendix 7, further comprising a second modulation section control section that detects a power abnormality from the plurality of optical modulators and transmits the shutdown signal.
(Appendix 11)
It has a radiation-resistant digital signal processor,
wherein the clock data regenerator power control unit is provided in the radiation-tolerant digital signal processing unit;
11. The optical transmitter according to any one of appendices 7 to 10.
(Appendix 12)
It has a radiation-resistant digital signal processor,
The signal interruption detection section, the clock data regenerator current anomaly detection section, and the clock data regenerator power supply control section are provided in the radiation-tolerant digital signal processing section.
11. The optical transmitter according to any one of appendices 7 to 10.
(Appendix 13)
An optical transmission control method for an optical communication device according to appendix 1,
detecting a current anomaly in the clock data regenerator;
detecting main signal interruption of the main signal from the clock data regenerator;
shutting down the high-power optical amplifier and the signal generator based on at least one of detection of the current anomaly of the clock data regenerator and detection of the main signal loss from the clock data regenerator;
stopping power supply to the clock data regenerator after shutting down the high-power optical amplifier and the signal generator;
Optical transmission control method.
(Appendix 14)
An optical transmission control method for an optical communication device according to appendix 1,
detecting a current anomaly in the clock data regenerator;
detecting main signal interruption of the main signal from the clock data regenerator;
shutting down the transmission laser unit based on at least one of detection of the current abnormality of the clock data regenerator and detection of the main signal interruption from the clock data regenerator;
stopping power supply to the clock data regenerator after shutting down the transmission laser unit;
Optical transmission control method.
(Appendix 15)
An optical transmission control method for an optical communication device according to appendix 2,
detecting a current abnormality in the plurality of clock data recovery circuits;
detecting main signal interruption of the plurality of main signals from the plurality of clock data recovery circuits;
the high-output optical amplifier and the signal based on at least one of detection of a current abnormality in one of the plurality of clock data recovery circuits and interruption of one of the plurality of main signals from the clock data recovery circuit; shut down the generator,
stopping power supply to the clock data regenerator after shutting down the high-power optical amplifier and the signal generator;
Optical transmission control method.
(Appendix 16)
An optical transmission control method for an optical communication device according to appendix 2,
detecting a current abnormality in the plurality of clock data recovery circuits;
detecting main signal interruption of the plurality of main signals from the plurality of clock data recovery circuits;
shutting down the transmission laser unit based on at least one of detection of a current abnormality in one of the plurality of clock data recovery circuits and interruption of one of the plurality of main signals from the clock data recovery circuit;
stopping power supply to the clock data regenerator after shutting down the transmission laser unit;
Optical transmission control method.
(Appendix 17)
An optical transmission control method for an optical communication device according to appendix 3,
detecting a current anomaly in the clock data regenerator;
detecting a power abnormality in the power from the phase modulation unit;
detecting main signal interruption of the main signal from the clock data regenerator;
shutting down the high-power optical amplifier and the signal generator based on detection of at least one of the current anomaly, the power anomaly, and the main signal loss;
stopping power supply to the clock data regenerator;
Optical transmission control method.
(Appendix 18)
An optical transmission control method for an optical communication device according to appendix 3,
detecting a current anomaly in the clock data regenerator;
detecting a power abnormality in the power from the phase modulation unit;
detecting main signal interruption of the main signal from the clock data regenerator;
shutting down the transmission laser unit based on detection of at least one of the current abnormality, the power abnormality, and the main signal loss;
stopping power supply to the clock data regenerator;
Optical transmission control method.
(Appendix 19)
An optical transmission control method for an optical communication device according to appendix 3,
detecting a current anomaly in the clock data regenerator;
detecting a power abnormality in the power from the phase modulation unit;
detecting main signal interruption of the main signal from the clock data regenerator;
shutting down the signal generator based on detection of at least one of the current abnormality, the power abnormality, and the main signal loss;
stopping power supply to the clock data regenerator;
changing the bias voltage value of the phase modulation unit at a slow start to control the power from the phase modulation unit in an increasing direction;
shutting down the high power optical amplifier;
Optical transmission control method.
(Appendix 20)
An optical transmission control method for an optical communication device according to appendix 4,
detecting a current abnormality in the plurality of clock data recovery circuits;
detecting a power anomaly in the power from the plurality of optical modulators;
detecting main signal interruption of the plurality of main signals from the plurality of clock data recovery circuits;
based on detection of at least one of a current anomaly in any one of the plurality of clock data regenerators, a power anomaly in any one of the plurality of optical modulators, and a loss of main signal in any one of the plurality of main signals; shut down the output optical amplifier,
shutting down the signal generator;
stopping power supply to the plurality of clock data recovery circuits;
Optical transmission control method.
(Appendix 21)
An optical transmission control method for an optical communication device according to appendix 4,
detecting a current abnormality in the plurality of clock data recovery circuits;
detecting a power anomaly in the power from the plurality of optical modulators;
detecting main signal interruption of the plurality of main signals from the plurality of clock data recovery circuits;
the transmission based on detection of at least one of a current abnormality in any one of the plurality of clock data regenerators, a power abnormality in any one of the plurality of optical modulators, and a main signal loss in any one of the plurality of main signals Shut down the laser section,
shutting down the signal generator;
stopping power supply to the plurality of clock data recovery circuits;
Optical transmission control method.
(Appendix 22)
An optical transmission control method for an optical communication device according to appendix 4,
detecting a current abnormality in the plurality of clock data recovery circuits;
detecting a power anomaly in the power from the plurality of optical modulators;
detecting main signal interruption of the plurality of main signals from the plurality of clock data recovery circuits;
the signal based on detection of at least one of a current anomaly in any one of the plurality of clock data regenerators, a power anomaly in any one of the plurality of optical modulators, and a loss of main signal in any one of the plurality of main signals; shut down the generator,
stopping power supply to the plurality of clock data recovery circuits;
changing the bias voltage values of the plurality of phase modulators at a slow start to control the power from the plurality of phase modulators in an increasing direction;
shutting down the high power optical amplifier;
Optical transmission control method.

Although the present invention has been described with reference to the embodiments, the present invention is not limited to the above embodiments. Various changes that can be understood by those skilled in the art can be made to the configuration and details of the present invention within the scope of the present invention.

INDUSTRIAL APPLICABILITY The present invention is applicable to, for example, an inter-satellite optical space communication system, an inter-terrestrial optical space communication system, and a terrestrial optical space communication system.

10, 10a, 10b, 10c, 10d, 10e Optical transmitters 10f, 10g, 10h, 10i, 10j, 10k Optical transmitters 20, 20a, 20b, 20c, 20d, 20e Digital signal processors 20f, 20g, 20h, 20i , 20j, 20k Digital signal processors 21, 21a, 21b, 21c Radiation-tolerant digital signal processors 21d, 21e, 21f, 21g Radiation-tolerant digital signal processors 30, 30a, 30b, 30c Optical transmitters 40, 40a High Output optical amplifiers 50, 50a, 50b, 50c, 50d, 50e Optical communication devices 50f, 50g, 50h, 50i, 50j, 50k Optical communication devices 210, 210a, 210b, 210c Signal generators 220, 220a Signal interruption detectors 230, 230a, 230b, 230c clock data regenerator power supply control unit 240, 240a clock data regenerator current abnormality detection unit 250, 250a modulation unit control unit 310 transmission laser unit 320, 320a phase modulation unit 330, 331 clock data regenerator 330a, 330b Clock data recovery circuits 340, 340a Clock data recovery current monitoring units 350, 350a Clock data recovery power supply units 360, 360a IQ modulation units 361a, 361b, 361c, 361d Optical modulators 362, 362a Bias voltage control units 363a, 363b , 363c, 363d, 363e optical splitter 364a, 364b, 364c, 364d photoelectric converter 365, 365a optical phase adjuster 410 power supply 420 excitation laser controller 430a, 430b excitation laser current controller 440a, 440b digital/analog converter 450a, 450b excitation laser section 460 pre-light amplification section 470 booster light amplification section

Claims (10)

a signal generator that generates a main signal;
a clock data regenerator that equalizes the waveform of the main signal;
a transmission laser unit that outputs laser light;
a phase modulation unit that phase-modulates the laser light based on the waveform-equalized main signal and outputs an optical phase-modulated signal;
a high-power optical amplifier that amplifies the optical phase-modulated signal with high-power light;
a clock data regenerator current anomaly detector for detecting a current anomaly of the clock data regenerator and shutting down the high-power optical amplifier and the signal generator;
a signal interruption detection unit that detects a main signal interruption from the clock data regenerator and shuts down the high-output optical amplifier and the signal generation unit;
a clock data regenerator power control unit that stops power supply to the clock data regenerator after shutting down the high-output optical amplifier and the signal generation unit;
An optical communication device having The signal generator generates a plurality of main signals,
The clock data regenerator has a plurality of clock data regenerating circuits for waveform equalization of the plurality of main signals,
the clock data regenerator current anomaly detector detects a current anomaly of the plurality of clock data regenerator circuits and shuts down the high-power optical amplifier and the signal generator;
The signal loss detection unit detects a main signal loss of the plurality of main signals and shuts down the high-power optical amplifier and the signal generation unit.
The optical communication device according to claim 1. 2. The optical communication device according to claim 1, further comprising a first modulation section control section for detecting a power abnormality from said phase modulation section and shutting down said high-output optical amplifier and said signal generation section. The phase modulation unit includes a plurality of optical modulators that perform phase modulation based on each of the plurality of waveform-equalized main signals and output optical phase-modulated signals,
3. The optical communication apparatus according to claim 2, further comprising a second modulator controller that detects power anomalies from said plurality of optical modulators and shuts down said high-output optical amplifier and said signal generator. It has a radiation-resistant digital signal processor,
wherein the clock data regenerator power control unit is provided in the radiation-tolerant digital signal processing unit;
5. The optical communication device according to claim 1. It has a radiation-resistant digital signal processor,
The signal interruption detection section, the clock data regenerator current anomaly detection section, and the clock data regenerator power supply control section are provided in the radiation-tolerant digital signal processing section.
5. The optical communication device according to claim 1. An optical transmitter that outputs an optical phase-modulated signal to a high-power optical amplifier,
a signal generator that generates a main signal;
a clock data regenerator that equalizes the waveform of the main signal;
a transmission laser unit that outputs laser light;
a phase modulation unit that phase-modulates the laser light based on the waveform-equalized main signal and outputs the optical phase-modulated signal;
a clock data regenerator current anomaly detector for detecting a current anomaly of the clock data regenerator and shutting down the high-power optical amplifier and the signal generator;
a signal interruption detection unit that detects a main signal interruption of the main signal from the clock data regenerator and shuts down the high-output optical amplifier and the signal generation unit;
a clock data regenerator power control unit that stops power supply to the clock data regenerator after shutting down the high-output optical amplifier and the signal generation unit;
an optical transmitter having a An optical transmission control method for an optical communication device according to claim 1 or 2,
detecting a current anomaly in the clock data regenerator;
detecting main signal interruption of the main signal from the clock data regenerator;
shutting down the high-power optical amplifier and the signal generator based on at least one of detection of the current anomaly of the clock data regenerator and detection of the main signal loss from the clock data regenerator;
stopping power supply to the clock data regenerator after shutting down the high-power optical amplifier and the signal generator;
Optical transmission control method. An optical transmission control method for an optical communication device according to claim 3 or 4,
detecting a current anomaly in the clock data regenerator;
detecting a power abnormality in the power from the phase modulation unit;
detecting main signal interruption of the main signal from the clock data regenerator;
shutting down the high-power optical amplifier and the signal generator based on detection of at least one of the current anomaly, the power anomaly, and the main signal loss;
stopping power supply to the clock data regenerator;
Optical transmission control method. An optical transmission control method for an optical communication device according to claim 3 or 4,
detecting a current anomaly in the clock data regenerator;
detecting a power abnormality in the power from the phase modulation unit;
detecting main signal interruption of the main signal from the clock data regenerator;
shutting down the signal generator based on detection of at least one of the current abnormality, the power abnormality, and the main signal loss;
stopping power supply to the clock data regenerator;
changing the bias voltage value of the phase modulation unit at a slow start to control the power from the phase modulation unit in an increasing direction;
shutting down the high power optical amplifier;
Optical transmission control method.

Images