JP3085240B2 - WDM system - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a wavelength division multiplexing / demultiplexing system, and more particularly to a wavelength division multiplexing / demultiplexing system combining a wavelength division multiplexing device for multiplexing optical signals of a plurality of different wavelengths by wavelength division multiplexing and a hitless path switching device.

[0002]

2. Description of the Related Art Conventionally, in this type of wavelength division multiplexing / demultiplexing system, as shown in FIG.
0, 30, 40, and uninterrupted path switching devices (SW) 5 to 8
It is composed of

Each of the wavelength multiplexing devices 10, 20, 30, 40 includes a multiplexer 12, 22, 32, 42 and a transmitting side amplifier 1
3, 23, 33, 43 and the receiving amplifiers 14, 24, 3
4, 44, demultiplexers 15, 25, 35, 45, and wavelength selection filters (BPF) 16 to 19, 26 to 29, 36 to
39, 46 to 49.

[0004] Each of the multiplexers 12, 22, 32, and 42 inputs optical signals of a plurality of different wavelengths from a plurality of optical transmitting terminal equipments (not shown) via path switches 5-8. Then, each optical signal is multiplexed. Transmitter amplifiers 13, 23, 3
3 and 43 amplify the output light from each of the multiplexers 12, 22, 32 and 42 and output the amplified light to the 0-system transmission line and the 1-system transmission line.

Each of the receiving amplifiers 14, 24, 34, and 44 amplifies an optical multiplexed signal input via a 0-system transmission line and a 1-system transmission line. Demultiplexers 15, 25, 35, 45 and wavelength selection filters 16-19, 26-29, 36-39,
46 to 49 are receiving amplifiers 14, 24, 34, 44, respectively.
Each of the amplified optical multiplexed signals is separated and output to the non-interruptible path switching devices 5 to 8.

Each of the non-interruptible path switching devices 5 to 8 includes a duplexer 1
5, 25, 35, 45 and wavelength selection filters 16-1
The optical signals separated at 9, 26 to 29, 36 to 39, and 46 to 49 are output to an optical receiving terminal device (not shown).
Each of the uninterrupted path switching devices 5 to 8 has a function of switching each optical signal between the optical transmitting terminal apparatus and the optical receiving terminal apparatus in signal units and without interruption.

In the wavelength division multiplexing / demultiplexing system having the above configuration, the wavelength division multiplexing apparatuses 10 and 20 to the wavelength division multiplexing apparatus 3
The operation when transmitting to 0, 40 will be described. In the wavelength division multiplexing device 10, an uninterruptible path switching device 5 having a switching function
The optical signal of wavelength λ1 from the optical transmission terminal transmitted from the optical transmission terminal is transmitted together with the wavelength λn (≠ λ1) from another optical transmission terminal transmitted from another optical transmission terminal transmitted through another hitless path switching device 6. Wavelength multiplexing is performed on the wavelengths λ1 to λn by the wave device 12. The optical signal multiplexed to the wavelengths λ1 to λn is transmitted to the transmission line after the optical output power is amplified by the transmitting amplifier 13.

In the wavelength multiplexing device 30, the optical multiplexed signal attenuated through the transmission line is amplified by the receiving amplifier 34, and then the wavelengths λ1 to λn are separated by the demultiplexer 35 and the wavelength selection filters 36 to 39. . The separated optical signals are again passed to the uninterrupted path switching devices 7 and 8, and the uninterrupted path switching is performed by the uninterrupted path switching devices 7 and 8, and transmitted to the optical receiving terminal device.

[0009]

In the transmission line switching method of the conventional wavelength division multiplexing / demultiplexing system described above, if a wavelength-multiplexed signal has a failure, the downstream uninterrupted path switching device independently performs switching. As a result, one uninterrupted path switching device uses the 0-system transmission line and another uninterrupted path switching device uses the 1-system transmission line. Sometimes it becomes.

For example, as shown in FIG. 2, when a failure occurs in an optical signal from the uninterrupted path switching device 5 to the wavelength multiplexing device 10, the uninterrupted path switching device 5 is connected to the 1-system transmission line on the transmission side. The non-instantaneous path switching device 6 uses the 0-system transmission line, and the non-instantaneous path switching device 7 corresponding to the non-instantaneous path switching device 5 switches the 1-system transmission line to the non-instantaneous path switching on the receiving side. The uninterruptible path switching device 6 corresponding to the device 6 uses the 0-system transmission line, and both the 0-system transmission line and the 1-system transmission line become active for both systems.

If the cause of the above fault is on the wavelength multiplexing device side, maintenance is performed after all the instantaneous uninterrupted path switching devices are artificially and simultaneously switched so as not to affect the working line. Work needs to be done.

Accordingly, an object of the present invention is to solve the above-mentioned problems and to enable the non-operating line construction of the optical multiplexed signal without any instantaneous interruption when there is a failure on the wavelength multiplexing side. It is an object of the present invention to provide a wavelength division multiplexing / demultiplexing system capable of preventing continuous use in a state where a failure has occurred.

[0013]

SUMMARY OF THE INVENTION A wavelength division multiplexing / demultiplexing system according to the present invention comprises a multiplexer for multiplexing optical signals of a plurality of different wavelengths on a transmission side, and an output light multiplexed by the multiplexer. A transmitting side amplifier for amplifying an optical multiplexed signal input from the transmitting side amplifier on the receiving side; and a demultiplexer for separating the optical multiplexed signal amplified by the receiving side amplifier. A wavelength division multiplexing / demultiplexing system including a receiver and a wavelength selection filter on the receiving side, wherein a plurality of alarm detection circuits for monitoring each of the plurality of optical signals having different wavelengths, and at least one of the plurality of alarm detection circuits And control means for controlling to reduce the output of the transmission-side amplifier when an abnormality is detected.

Another wavelength division multiplexing / demultiplexing system according to the present invention comprises a plurality of different wavelength multiplexing / demultiplexing systems from an optical transmitting terminal having redundancy switching.
The optical signal of a certain wavelength is input, a multiplexer for multiplexing each optical signal, and a transmitting amplifier for amplifying the output light multiplexed by the multiplexer are included in the transmitting side, and the transmitting side includes the transmitting side amplifier. A receiving amplifier for amplifying an optical multiplexed signal input from a receiving amplifier, a demultiplexer and a wavelength separator for separating the optical multiplexed signal amplified by the receiving amplifier and outputting the separated optical multiplexed signal to an optical receiving terminal device having redundancy switching A wavelength division multiplexing / demultiplexing system including a selection filter on a receiving side, wherein at least one of a plurality of alarm detection circuits for monitoring each optical signal from the optical transmitting terminal device and the plurality of alarm detection circuits. Control means for controlling the output of the transmission-side amplifier to reduce the output of the optical receiving terminal to such an extent that the redundancy switching occurs when an abnormality is detected.

Another wavelength division multiplexing / demultiplexing system according to the present invention is a system for transmitting an optical signal having a plurality of different wavelengths from an optical transmitting terminal equipment.
First and second hitless switching means switches the output to the people first and second transmission lines at each MuMadoka sectional, optical signals each from the first and second hitless switching means First and second multiplexers, respectively, and amplify the output light multiplexed by the first and second multiplexers and output the amplified light to the first and second transmission paths. First and second receiving amplifiers including first and second transmitting amplifiers on the transmitting side, and amplifying an optical multiplexed signal input via the first and second transmission paths on the receiving side, respectively. And first and second demultiplexers for separating the optical multiplexed signals amplified by the first and second receiving amplifiers, respectively, and optical signals from the first and second demultiplexers, respectively. A wavelength division multiplexing / demultiplexing system including a third and a fourth uninterruptible switching means for switching to an optical receiving terminal device without interruption and outputting the same to a receiving side, First and a second plurality of alarm detection circuit, said first and second light monitored by a plurality of alarm detection circuit each respectively monitors the optical signals each from the first and second hitless switching means At least one of the signals
When an abnormality is detected in step (1) , the first and second output side amplifiers are controlled so as to reduce the output to such an extent that the third and fourth instantaneous interruption switching means are switched. And the second
Control means.

That is, in the wavelength division multiplexing / demultiplexing system of the present invention, a multiplexer for inputting a plurality of optical signals having different wavelengths and multiplexing the respective optical signals, and a transmitting amplifier for amplifying the output light are provided on the transmitting side. A receiving side amplifier for amplifying a multiplexed input optical signal, a demultiplexer and a wavelength selection filter for separating an optical multiplexed signal on the receiving side, and an optical switch having a redundant switch for connecting each wavelength. An alarm detection circuit for monitoring the signal output from the terminal device, an OR circuit for performing an OR operation on the output of the alarm detection circuit for each wavelength, and controlling the output of the transmitting amplifier based on the output of the OR circuit. An excitation LD control circuit.

Thus, even if a failure occurs on the wavelength division multiplexing side, not only the failed signal but also the output of all the signals of the system used at the time of the failure occur to such an extent that the system switching is performed. Since the system switching is performed by all non-interruptible path switching devices, it is possible to construct a non-operational line of an optical multiplexed signal without an instantaneous interruption when there is a failure on the wavelength multiplexing side. It is possible to prevent continuous use in a state where a failure such as system active occurs.

[0018]

Next, an embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a block diagram showing a system configuration according to an embodiment of the present invention. In the figure, a wavelength division multiplexing / demultiplexing system according to an embodiment of the present invention comprises wavelength division multiplexers 1 to 4 and non-interruptible path switching devices (SW) 5 to 8. The configuration is the same as that of the conventional example shown in FIG. 2 except that the output control circuits 11, 21, 31, and 41 are provided. In this configuration, the same components are denoted by the same reference numerals, and the operation is the same as in the conventional example.

That is, each of the wavelength division multiplexers 1 to 4 includes an output control circuit 11, 21, 31, and 41, and a multiplexer 12, 2.
2, 32, 42 and the transmission side amplifiers 13, 23, 33, 4
3, receiving amplifiers 14, 24, 34, 44, demultiplexers 15, 25, 35, 45, and a wavelength selection filter (BP
F) 16-19, 26-29, 36-39, 46-49
It is composed of

The output control circuits 11, 21, 31, 41 are respectively provided with alarm detection circuits (ALM) 11a to 11d, 21a to 2
1d, 31a to 31d, 41a to 41d, OR (logical sum) circuits 11e, 21e, 31e, 41e, and excitation LD
(Laser Driver) Control Circuits 11f, 21f, 31f,
41f.

Each of the multiplexers 12, 22, 32, and 42 receives optical signals of a plurality of different wavelengths from a plurality of optical transmitting terminal units (not shown) via non-interruptible path switching devices 5 to 8. Then, each optical signal is multiplexed. Transmitter amplifiers 13, 23, 3
3 and 43 amplify the output light from each of the multiplexers 12, 22, 32 and 42 and output the amplified light to the 0-system transmission line and the 1-system transmission line.

Each of the receiving side amplifiers 14, 24, 34, and 44 amplifies an optical multiplexed signal input through the 0-system transmission line and the 1-system transmission line. Demultiplexers 15, 25, 35, 45 and wavelength selection filters 16-19, 26-29, 36-39,
46 to 49 are receiving amplifiers 14, 24, 34, 44, respectively.
Each of the amplified optical multiplexed signals is separated and output to the non-interruptible path switching devices 5 to 8.

In the wavelength division multiplexing / demultiplexing system according to an embodiment of the present invention, a plurality of optical signals having different wavelengths transmitted from the optical transmitting terminal through the uninterrupted path switching devices 5 to 8 on the transmitting side are transmitted to the multiplexer 12. , 22, 32, and 42 before output to the alarm detection circuit 1 of each of the output control circuits 11, 21, 31, and 41.
1a to 11d, 21a to 21d, 31a to 31d, 41
Monitoring is performed for each wavelength by a to 41d.

Alarm detection circuits 11a to 11d, 21a to 2
The monitoring results of 1d, 31a to 31d, and 41a to 41d are ORed by the OR circuits 11e, 21e, 31e, and 41e, and the pump LD control circuits 11f, 21f, 31f, The control is possible at 41f.

The optical multiplexed signals multiplexed by the multiplexers 12, 22, 32, 42 are transmitted to the transmission side amplifiers 13, 23, 3 respectively.
The signal is amplified at 3, 43 and transmitted to the transmission path. At this time, the excitation LD control circuits 11f, 21f, 31f,
41f is an amplification transmitting side amplifier 13, 23, 33, 4 according to the output result of the OR circuits 11e, 21e, 31e, 41e.
3 controls the amplification of the output power of the optical multiplex signal.

On the receiving side, the optical multiplexed signal input via the 0-system transmission line and the 1-system transmission line is converted into the receiving amplifiers 14, 24,
Amplify at 34, 44 and splitters 15, 25, 35, 45 and wavelength selection filters 16-19, 26-29, 36-3
9, 46-49. Demultiplexer 15, 25, 3
5, 45 and wavelength selection filters 16 to 19, 26 to 2
The optical signals of the respective wavelengths separated at 9, 36 to 39 and 46 to 49 are output to the uninterrupted path switching devices 7 and 8, and are transmitted from the uninterrupted path switching devices 7 and 8 to the respective optical receiving terminal devices (FIG. (Not shown).

When one of the optical signals from the transmitting side causes a failure in the input sections of the wavelength division multiplexers 1-4, the alarm detection circuits 11a-11d, 21a-2 corresponding to the optical signals.
An abnormality is detected by 1d, 31a to 31d, and 41a to 41d. The alarm detection circuits 11a to 11d and 21a
21d, 31a to 31d, and 41a to 41d are input to the OR circuits 11e, 21e, 31e, and 41e, and then are supplied from the OR circuits 11e, 21e, 31e, and 41e to the excitation LD control circuits 11f, 21f, 31f, and 41f. Is input to

The optical multiplexed signals multiplexed by the multiplexers 12, 22, 32, 42 are transmitted to the transmission side amplifiers 13, 23, 33,
Amplified by the excitation LD control circuit 11f,
21f, 31f, 41f are OR circuits 11e, 21e, 3
In response to the notification from 1e and 41e, the transmission side amplifiers 13, 23, 33 and 43 are controlled so that their outputs are reduced to such an extent that switching between the 0-system transmission line and the 1-system transmission line occurs.
Therefore, the optical multiplexed signal from the transmission-side amplifiers 13, 23, 33, and 43 to the transmission path is transmitted with the output power reduced.

On the receiving side, the input optical multiplexed signal is amplified by the receiving side amplifiers 14, 24, 34, and 44.
5, 25, 35, 45 and wavelength selection filters 16-1
After being separated at 9, 26 to 29, 36 to 39 and 46 to 49, the signals are output to the hitless path switching devices 7 and 8 and transmitted from the hitless path switching devices 7 and 8 to the respective optical receiving terminal devices. You.

At this time, the transmitting amplifiers 13, 23, 33,
Since the power of the optical multiplex signal from 43 is reduced, the power of all the wavelengths λ1 to λn after separation is also reduced. Therefore, for wavelengths other than the wavelength at which the fault occurred,
The instantaneous uninterrupted path switching devices 5 to 8 perform switching at the same time, and a spare transmission path for an optical multiplex signal is constructed.

Next, a case where a failure occurs in an optical signal of wavelength λ1 from the uninterrupted path switching device 5 to the wavelength multiplexing device 1 will be described with reference to FIG.

When a failure occurs in the optical signal of the wavelength λ1 transmitted from the uninterrupted path switching device 5 to the wavelength multiplexing device 1 on the transmitting side, the optical signal of the wavelength λ1 is monitored before being input to the multiplexer 12. The alarm detection circuit 11a outputs a signal indicating that a failure has occurred to the OR circuit 11e.

The OR circuit 11e receives the signal of the fault occurrence detection from the alarm detection circuit 11a as it is,
f, 21f, 31f, and 41f, so that the excitation LD
The control circuit 11f controls the output of the transmission-side amplifier 13 to decrease in response to the notification from the OR circuit 11e.
Therefore, the optical multiplexed signal from the transmission side amplifier 13 to the system 0 transmission line is transmitted with its output power reduced.

On the receiving side, the input optical multiplexed signal is amplified by the receiving side amplifier 34 and separated by the demultiplexer 35 and the wavelength selection filters 36 to 39.
8, the power of the optical multiplexed signal is reduced, so that the uninterruptible path switching devices 7 and 8 operate at the wavelength λ 1
Switching is also performed simultaneously for other wavelengths λ2 to λn. That is, the instantaneous interruption path switching devices 7 and 8 perform an instantaneous interruption switching from the 0-system transmission path to the 1-system transmission path, so that a spare transmission path for the optical multiplexed signal is constructed.

As described above, the multiplexers 12, 22, 32, 4
Before inputting to the optical signal 2, the optical signal is detected for each wavelength by the alarm detection circuit 11a.
~ 11d, 21a ~ 21d, 31a ~ 31d, 41a ~
Monitoring at 41d, alarm detection circuits 11a to 11d, 21a
LD control circuits 11f, 21d when any one of .about.21d, 31a-31d, 41a-41d detects a fault.
f, 31f and 41f are amplification transmitting side amplifiers 13, 23 and 3
By controlling the output power of the optical multiplexed signal by the third and fourth channels 43 and 43 to decrease, the instantaneous uninterrupted path switching devices 5 to 8 on the receiving side simultaneously perform switching to wavelengths other than the wavelength in which the fault has occurred. Therefore, when there is a failure on the wavelength multiplexing side, the non-operating line of the optical multiplexed signal can be constructed without any interruption, and the line failure can be quickly restored, and the unstable one-way operation state Can be avoided in a shorter time.

[0036]

As described above, according to the present invention, each of a plurality of optical signals of different wavelengths is monitored, and when an abnormality is detected in at least one of the optical signals, the signal is transmitted to the receiving side. By controlling the output power at the time of switching to the extent that switching of the system occurs, it is possible to construct a non-operating line of an optical multiplex signal without instantaneous interruption when there is a failure on the wavelength multiplex side, There is an effect that it is possible to prevent continuous use in a state in which a failure such as that in which both systems are active has occurred.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a system configuration according to an embodiment of the present invention.

FIG. 2 is a block diagram showing a system configuration according to a conventional example.

[Explanation of symbols]

1-4 wavelength multiplexing apparatus 5-8 uninterrupted path switching apparatus 11, 21, 31, 41 output control circuit 12, 22, 32, 42 multiplexer 13, 23, 33, 43 transmission side amplifier 14, 24, 34 , 44 Receiver amplifier 15, 25, 35, 45 Demultiplexer 16-19, 26-29, 36-39, 46-49 Wavelength selection filter 11a-11d, 21a-21d, 31a-31d, 4
1a to 41d Alarm detection circuit 11e, 21e, 31e, 41e OR circuit 11f, 21f, 31f, 41f Excitation LD control circuit

──────────────────────────────────────────────────の Continued on the front page (51) Int.Cl. ⁷ identification code FI H04J 14/02 (58) Fields investigated (Int.Cl. ⁷ , DB name) H04L 1/22 H04B 1/74 H04B 10/08 H04J 14/02

Claims (6)

(57) [Claims] 1. A transmitting side comprising: a multiplexer for multiplexing optical signals of a plurality of different wavelengths on a transmitting side; and a transmitting amplifier for amplifying output light multiplexed by the multiplexer. Wavelength multiplexing including, on the receiving side, a receiving amplifier that amplifies an optical multiplexed signal input from the transmitting amplifier on the side thereof, and a demultiplexer and a wavelength selection filter that separates the optical multiplexed signal amplified by the receiving amplifier. A separation system, wherein a plurality of alarm detection circuits that monitor each of the plurality of different wavelength optical signals, and a transmission side amplifier when an abnormality is detected in at least one of the plurality of alarm detection circuits. Control means for controlling the output to decrease. 2. An arithmetic unit for performing a logical sum operation of detection results of each of the plurality of alarm detection circuits, wherein the control unit controls an output of the transmission-side amplifier based on an operation result of the arithmetic unit. 2. The wavelength division multiplexing / demultiplexing system according to claim 1, wherein: 3. A multiplexer for inputting optical signals of a plurality of different wavelengths from an optical transmitting terminal having redundancy switching and multiplexing the respective optical signals, and an output multiplexed by the multiplexer. A transmitting amplifier that amplifies light is included on the transmitting side, and a receiving amplifier that amplifies an optical multiplexed signal input from the transmitting amplifier on the receiving side, and an optical multiplexed signal amplified by the receiving amplifier is separated. A wavelength division multiplexing / demultiplexing system including, on the receiving side, a demultiplexer and a wavelength selection filter for outputting to an optical receiving terminal device having redundancy switching, wherein a plurality of optical signals from the optical transmitting terminal device are monitored. When an abnormality is detected in at least one of the plurality of alarm detection circuits, the output of the transmission side amplifier is reduced to such an extent that the redundant switching occurs in the optical reception terminal device. Control means to control Wavelength demultiplexing system, characterized by. 4. An arithmetic unit for performing a logical sum operation of detection results of each of the plurality of alarm detection circuits, wherein the control means controls an output of the transmission side amplifier based on a calculation result of the calculation means. 4. The wavelength division multiplexing / demultiplexing system according to claim 3, wherein: 5. A first and second uninterruptible switching means for switching the output of each of a plurality of optical signals of different wavelengths from the optical transmitting terminal equipment to the first and second transmission paths without an instantaneous interruption, respectively. And first and second multiplexers for respectively multiplexing the optical signals from the first and second non-interruptible switching means, respectively, and multiplexed by the first and second multiplexers. The transmission side includes first and second transmission-side amplifiers for amplifying output light and outputting the amplified light to the first and second transmission paths, respectively. The reception side includes the first and second transmission paths via the first and second transmission paths. First and second receiving-side amplifiers for respectively amplifying input optical multiplexed signals, and first and second demultiplexers for respectively separating optical multiplexed signals amplified by the first and second receiving-side amplifiers Third and fourth instantaneous switches for switching the optical signals from the first and second demultiplexers without interruption and outputting the signals to the optical receiving terminal device, respectively. A wavelength division multiplexing / demultiplexing system including a switching unit on a receiving side, wherein first and second plurality of alarm detection circuits respectively monitoring the optical signals from the first and second hitless switching units, When an abnormality is detected in at least one of the optical signals monitored by each of the first and second plurality of alarm detection circuits, the output of the first and second transmission-side amplifiers is changed to the third signal. And a first and a second control means for controlling the switching to a degree at which the switching of the fourth non-interruptible switching means occurs. 6. A method according to claim 1, further comprising: first and second operation means for performing a logical sum operation of the detection results of the first and second alarm detection circuits, respectively, wherein the first and second control means execute the first and second control means. 6. The wavelength division multiplexing / demultiplexing system according to claim 5, wherein outputs of said first and second transmitting side amplifiers are respectively controlled based on a calculation result of said second calculation means.