JP4507225B2 - Optical characteristic measuring apparatus, method, and recording medium - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to dispersion measurement of optical transmission devices such as optical fibers.
[0002]
[Prior art]
In the case of transmitting light over a long distance, the loss is large if the light is transmitted only by an optical fiber. Therefore, loss is prevented by using an optical fiber line that combines an optical fiber with an optical amplifier (EDFA) that amplifies an optical signal. An optical amplifier passes light only in one direction. Therefore, in order to perform bidirectional communication, a single optical fiber line that transmits light in a certain direction and a single optical fiber line that transmits light in a direction opposite to a certain direction are combined. Use a cable. This cable is called one fiber pair.
[0003]
Here, when performing dispersion measurement through variable wavelength light using one fiber pair as a device under test (DUT: Device Under Test), it is already necessary for the communication required to pass the reference light and perform measurement control. It is necessary to prepare one fiber pair. That is, two fiber pairs are required.
[0004]
FIG. 5 shows the configuration of an optical dispersion measurement system when one fiber pair in the prior art is a DUT. A two-fiber pair 300 includes a DUT 310 and a reference line 320, and includes optical fiber lines 310a, 310b, 320a, and 320b, respectively.
[0005]
A master measuring instrument 100 is connected to one end of the two-fiber pair 300, and a slave measuring instrument 200 is connected to the other end. The optical fiber lines 310a and 320a transmit light from the master measuring instrument 100 to the slave measuring instrument 200, and the optical fiber lines 310b and 320b transmit light from the slave measuring instrument 200 to the master measuring instrument 100.
[0006]
The variable wavelength light generated by the variable wavelength light source 102 is modulated by the optical modulator 112 and is incident on the optical fiber line 310 a of the DUT 310. The fixed wavelength light generated by the fixed wavelength light source 104 is modulated by the optical modulator 114 and is incident on the optical fiber line 320 a of the reference line 320. Then, the phase comparator 210 compares the phase of the variable wavelength light and the fixed wavelength light transmitted through the optical fiber lines 310a and 320a, and measures the chromatic dispersion of the DUT 310.
[0007]
At this time, the measurement condition setting unit 120 sets chromatic dispersion measurement conditions. The measurement control unit 220 measures chromatic dispersion measurement data based on the measurement conditions set by the measurement condition setting unit 120 and transmits the measurement data to the measurement condition setting unit 120. Thus, the measurement condition setting unit 120 and the measurement control unit 220 need to communicate with each other. Therefore, communication is performed from the measurement control unit 120 to the measurement control unit 220 using the optical fiber line 320a and from the measurement control unit 220 to the measurement control unit 120 using the optical fiber line 320b.
[0008]
[Problems to be solved by the invention]
However, in the configuration as described above, one fiber pair called the reference line 320 is further required for communication between the measurement control unit 120 and the measurement control unit 220.
[0009]
Therefore, an object of the present invention is to provide an apparatus and the like that can measure chromatic dispersion characteristics without requiring one fiber pair in addition to a DUT.
[0010]
[Means for Solving the Problems]
The present invention Is a device for measuring characteristics of an object to be measured that transmits light, and generates measurement condition setting means for setting measurement conditions for measuring characteristics of the object to be measured, and variable wavelength light and fixed wavelength light. A light generating means, a characteristic measuring means for measuring the characteristic of the object to be measured based on the variable wavelength light and the fixed wavelength light transmitted through the object to be measured, a measurement control means for controlling the characteristic measuring means based on the measurement conditions, and a measurement condition Is transmitted to the measurement control unit, and the measurement control communication unit is configured to transmit the measurement result to the measurement condition setting unit.
[0011]
According to the optical characteristic measuring apparatus configured as described above, since the measurement control communication unit can communicate with the measurement control unit and the measurement condition setting unit, it is not necessary to newly prepare one fiber pair.
[0012]
The present invention Is a light generation device used in a device for measuring the characteristics of an object to be measured that transmits light, measuring condition setting means for setting measurement conditions for measuring the characteristics of the object to be measured, variable wavelength light and fixed A light generation unit configured to generate wavelength light; and a measurement control communication unit configured to transmit a measurement condition from the measurement condition setting unit and transmit a measurement result of the object to be measured to the measurement condition setting unit.
[0013]
The present invention Is a device for measuring the characteristics of an object to be measured that allows light to pass through, based on measurement conditions and characteristic measuring means for measuring the characteristics of the object to be measured based on variable wavelength light and fixed wavelength light transmitted through the object to be measured. Measurement control means for controlling the characteristic measurement means, and measurement control communication means for transmitting the measurement conditions to the measurement control means and transmitting the measurement result of the characteristic of the object to be measured from the measurement control means.
[0014]
In the present invention, The device under test has a first optical line and a second optical line that allow light to pass only in one direction, variable wavelength light is transmitted through the first optical line, and fixed wavelength light is transmitted through the second optical line. , Is You may do .
[0015]
In the present invention, The device under test has a first optical line and a second optical line that allow light to pass only in one direction, variable wavelength light is transmitted through the first optical line, and fixed wavelength light is transmitted through the second optical line. , Is You may do .
[0016]
In the present invention, The object to be measured passes light only in one direction, and the variable wavelength light and fixed wavelength light are combined and transmitted through the object to be measured. You may do .
[0017]
In the present invention, The object to be measured passes light only in one direction, and the variable wavelength light and fixed wavelength light are combined and transmitted through the object to be measured. You may do .
[0018]
In the present invention, The object to be measured passes light bidirectionally, the variable wavelength light and the fixed wavelength light are combined and transmitted through the object to be measured, and the measurement communication control means is common to the object to be measured. You may do .
[0019]
In the present invention, The object to be measured passes light bidirectionally, the variable wavelength light and the fixed wavelength light are combined and transmitted through the object to be measured, and the measurement communication control means is common to the object to be measured. You may do .
[0020]
In the present invention, The measurement control communication means is any one of a wired cable, a wireless communication means, and a satellite communication means. You may do .
[0021]
In the present invention, A first terminal that receives the combined light in which the variable wavelength light and the fixed wavelength light are combined, a light that is received by the first terminal, a second terminal that receives the light input, and a light that is received by the second terminal A third terminal, a second terminal connected to one end of the object to be measured, a third terminal connected to the measurement condition setting means, a first terminal receiving the measurement result, A second terminal that outputs light received by the first terminal and receives light input; and a third terminal that outputs light received by the second terminal; the second terminal is the other end of the object to be measured. The other end side circulator, the third terminal being connected to the measurement control means. May .
[0022]
The present invention Is a method for measuring characteristics of an object to be measured that transmits light, and generates a measurement condition setting step for setting measurement conditions for measuring the characteristics of the object to be measured, and variable wavelength light and fixed wavelength light. A light generation process, a characteristic measurement process for measuring characteristics of the measurement object based on variable wavelength light and fixed wavelength light transmitted through the measurement object, a measurement control process for controlling the characteristic measurement process based on measurement conditions, and measurement control A measurement control communication step of transmitting a measurement condition to a measurement control unit that performs the process and transmitting a measurement result to a measurement condition setting unit that performs the measurement condition setting step.
[0023]
The present invention Is a light generation method used for measuring the characteristics of an object to be measured that transmits light, a measurement condition setting step for setting measurement conditions for measuring the characteristics of the object to be measured, and variable wavelength light and fixed wavelength light. Measurement control for transmitting the measurement condition from the measurement condition setting means for performing the measurement condition setting process and transmitting the measurement result of the object to be measured to the measurement condition setting means for performing the measurement condition setting process And a communication step.
[0024]
The present invention Is a method for measuring characteristics of an object to be measured that transmits light, and is based on a characteristic measurement process for measuring characteristics of the object to be measured based on variable wavelength light and fixed wavelength light transmitted through the object to be measured, and measurement conditions. Measurement control process for controlling the characteristic measurement process and measurement control for transmitting measurement conditions to the measurement control means for performing the measurement control process and transmitting the measurement result of the characteristic of the object to be measured from the measurement control means for performing the measurement control process And a communication step.
[0025]
The present invention Is a computer-readable recording medium that records a program for causing a computer to execute a light generation process used in a process for measuring characteristics of an object to be measured that transmits light. Measurement condition setting processing for setting measurement conditions for light, light generation processing for generating variable wavelength light and fixed wavelength light, and characteristics of the measurement object based on variable wavelength light and fixed wavelength light transmitted through the measurement object Measured characteristic measurement processing, measurement control processing for controlling characteristic measurement processing based on measurement conditions, and measurement condition transmission means for transmitting measurement conditions to a measurement control unit for performing measurement control processing and performing measurement condition setting processing The computer-readable recording medium stores a program for causing a computer to execute measurement control communication processing for transmitting a measurement result.
[0026]
The present invention Is a computer-readable recording medium that records a program for causing a computer to execute a light generation process used in the light generation process used to measure the characteristics of the measurement object that transmits light. The measurement condition is transmitted from the measurement condition setting means for performing the measurement condition setting process for setting the measurement condition for the characteristic measurement, the light generation process for generating the variable wavelength light and the fixed wavelength light, and the measurement condition setting process. The computer-readable recording medium stores a program for causing a computer to execute a measurement control communication process for transmitting a measurement result of an object to be measured to a measurement condition setting unit that performs the measurement condition setting process.
[0027]
The present invention Is a computer-readable recording medium that records a program for causing a computer to execute a light generation process used in the process of measuring the characteristics of the measurement object that transmits light, and that has a variable wavelength transmitted through the measurement object. The measurement conditions are transmitted to the measurement control process that measures the characteristics of the object to be measured based on the light and the fixed wavelength light, the measurement control process that controls the characteristic measurement process based on the measurement conditions, and the measurement control means that performs the measurement control process. The computer-readable recording medium stores a program for causing a computer to execute a measurement control communication process for transmitting a measurement result of a characteristic of an object to be measured from a measurement control unit that performs the measurement control process.
[0028]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings.
[0029]
First embodiment
FIG. 1 shows an optical characteristic measuring apparatus according to a first embodiment of the present invention. The optical characteristic measuring apparatus has a master machine 10, a slave machine 20, and a measurement control communication means 40. The master machine 10 is connected to one end of the DUT 30, and the slave machine 20 is connected to the other end of the DUT 30.
[0030]
The DUT 30 includes a first optical fiber line 32 and a second optical fiber line 34. Both the first optical fiber line 32 and the second optical fiber line 34 have an optical amplifier, and therefore pass light only in one direction. Note that the light transmission directions of the first optical fiber line 32 and the second optical fiber line 34 are the same. For example, as shown in FIG. 1, light is transmitted from the master machine 10 to the slave machine 20.
[0031]
The master machine 10 includes a measurement condition setting unit 11, a variable wavelength light source 12, a fixed wavelength light source 14, and optical modulators 16 and 18.
[0032]
The measurement condition setting unit 11 is for setting measurement conditions for measuring the characteristics of the DUT 30. The measurement of the characteristics of the DUT 30 is performed by the slave device 20 as will be described later, but the initial setting and communication error recovery processing of the slave device 20 are performed based on the measurement conditions set by the measurement condition setting unit 11.
[0033]
The variable wavelength light source 12 generates variable wavelength light whose wavelength can be changed. The variable wavelength light source 12 can sweep the wavelength λx of the variable wavelength light. The first optical modulator 16 modulates variable wavelength light at a predetermined frequency f. The first optical modulator 16 generally has lithium niobate (LN), but may not have LN as long as modulation is possible. The light (first incident light) output from the first optical modulator 16 is incident on the first optical fiber line 32.
[0034]
The fixed wavelength light source 14 generates fixed wavelength light whose wavelength is fixed at λ0. The second optical modulator 18 modulates the variable wavelength light with the frequency f. The second optical modulator 18 modulates the fixed wavelength light with a predetermined frequency f. The second optical modulator 18 generally has lithium niobate (LN), but may not have LN as long as modulation is possible. The light (second incident light) output from the second optical modulator 18 is incident on the second optical fiber line 34.
[0035]
In addition, what remove | excluded the measurement condition setting part 11 from the master machine 10 is equivalent to a light production | generation means.
[0036]
The first incident light incident on the first optical fiber line 32 passes through the first optical fiber line 32. The light transmitted through the first optical fiber line 32 is referred to as first outgoing light. The second incident light incident on the second optical fiber line 34 passes through the second optical fiber line 34. The light transmitted through the second optical fiber line 34 is referred to as second outgoing light.
[0037]
The slave device 20 includes a first photoelectric converter 22, a second photoelectric converter 24, a phase comparator 26, a characteristic calculation unit 28, and a measurement control unit 29.
[0038]
The first photoelectric converter 22 converts the first emitted light into an electrical signal and outputs an electrical signal for measurement. The second photoelectric converter 24 converts the second emitted light into an electric signal and outputs a reference electric signal.
[0039]
The phase comparator 26 measures the phase of the measurement electric signal with reference to the reference electric signal.
[0040]
The characteristic calculator 28 calculates the group delay characteristic and the chromatic dispersion characteristic of the first optical fiber line 32 based on the phase measured by the phase comparator 26. The group delay characteristic can be calculated from the relationship between the phase measured by the phase comparator 26 and the modulation frequency f. The wavelength dispersion characteristic can be obtained by differentiating the group delay characteristic with respect to the wavelength.
[0041]
The measurement control unit 29 controls the characteristic calculation unit 28 based on the measurement conditions set by the measurement condition setting unit 11 and measures the characteristics of the DUT 30. In addition, the measurement control unit 29 transmits the measurement result of the characteristics of the DUT 30 to the measurement condition setting unit 11.
[0042]
In addition, what remove | excluded the measurement control part 29 from the slave machine 20 is equivalent to a characteristic measurement means.
[0043]
The measurement control communication unit 40 enables communication between the measurement condition setting unit 11 and the measurement control unit 29. Measurement conditions are transmitted from the measurement condition setting unit 11 to the measurement control unit 29 via the measurement control communication unit 40. Further, the measurement result of the characteristics of the DUT 30 is transmitted from the measurement control unit 29 to the measurement condition setting unit 11 via the measurement control communication unit 40. The measurement control communication unit 40 is, for example, one of a wired cable, a wireless communication unit, and a satellite communication unit.
[0044]
Next, the operation of the first embodiment will be described with reference to the flowchart of FIG. When the measurement is started, the measurement condition setting unit 11 on the master machine 10 side transmits a first command to the measurement control unit 29 via the measurement control communication unit 40 (S10). The first command is a command for setting measurement conditions.
[0045]
When receiving the first command (S20), the measurement control unit 29 on the slave device 20 side performs initial setting of the slave device 20, various processes, communication error return processing, and the like according to the content of the first command (S21). When the various processes are completed, the measurement control unit 29 transmits a reply command indicating that the various processes are completed to the measurement condition setting unit 11 via the measurement control communication unit 40 (S22).
[0046]
When the measurement condition setting unit 11 receives the reply command (S11), the wavelength of the variable wavelength light source 12 is changed (S12), and the second command is sent from the measurement condition setting unit 11 to the measurement control unit 29 via the measurement control communication unit 40. Transmit (S13). In other words, the second command is a signal that the first incident light and the second incident light for measurement are incident on the DUT 30. Then, the variable wavelength light source 12 enters the variable wavelength light, and the fixed wavelength light source 14 enters the fixed wavelength light (S14).
[0047]
The variable wavelength light is converted into first incident light by the first light modulator 16, and the fixed wavelength light is converted into second incident light by the second light modulator 18. The first incident light passes through the first optical fiber line 32 and becomes the first outgoing light. The second incident light passes through the second optical fiber line 34 and becomes the second outgoing light. The first outgoing light is converted into a measurement electric signal by the first photoelectric converter 22, and the second outgoing light is converted into a reference electric signal by the second photoelectric converter 24 and input to the phase comparator 26. The phase comparator 26 measures the phase of the measurement electric signal with reference to the reference electric signal. The characteristic calculator 28 calculates the group delay characteristic and the chromatic dispersion characteristic of the first optical fiber line 32 based on the phase measured by the phase comparator 26. The group delay characteristic can be calculated from the relationship between the phase measured by the phase comparator 26 and the modulation frequency f. The wavelength dispersion characteristic can be obtained by differentiating the group delay characteristic with respect to the wavelength.
[0048]
When the measurement control unit 29 receives the second command (S23), the characteristic calculation unit 28 calculates the characteristic of the DUT 30 (S24). And the measurement control part 29 transmits the measurement result of a characteristic to the measurement condition setting part 11 via the measurement control communication means 40 (S25).
[0049]
When the measurement condition setting unit 11 receives the measurement result (S15), the process returns to the transmission of the first command (S10). Then, the process is terminated by turning off the power of the master machine 10 at an arbitrary time.
[0050]
According to the first embodiment, since the communication between the measurement condition setting unit 11 and the measurement control unit 29 can be performed via the measurement control communication unit 40, it is not necessary to newly prepare one fiber pair.
[0051]
Second embodiment
The second embodiment differs from the first embodiment in that the DUT 30 transmits light only in one direction.
[0052]
An optical characteristic measuring apparatus according to the second embodiment of the present invention is shown in FIG. The optical characteristic measuring apparatus has a master machine 10, a slave machine 20, and a measurement control communication means 40. The master machine 10 is connected to one end of the DUT 30, and the slave machine 20 is connected to the other end of the DUT 30.
[0053]
The DUT 30 passes light only in one direction. For example, as shown in FIG. 3, light is transmitted from the master machine 10 to the slave machine 20.
[0054]
The master machine 10 includes a measurement condition setting unit 11, a variable wavelength light source 12, a fixed wavelength light source 14, optical modulators 16 and 18, and a coupler 19.
[0055]
The measurement condition setting unit 11 is for setting measurement conditions for measuring the characteristics of the DUT 30. The measurement of the characteristics of the DUT 30 is performed by the slave device 20 as will be described later, but the initial setting and communication error recovery processing of the slave device 20 are performed based on the measurement conditions set by the measurement condition setting unit 11.
[0056]
The variable wavelength light source 12 generates variable wavelength light whose wavelength can be changed. The variable wavelength light source 12 can sweep the wavelength λx of the variable wavelength light. The first optical modulator 16 modulates variable wavelength light at a predetermined frequency f. The first optical modulator 16 generally has lithium niobate (LN), but may not have LN as long as modulation is possible.
[0057]
The fixed wavelength light source 14 generates fixed wavelength light whose wavelength is fixed at λ0. The second optical modulator 18 modulates the variable wavelength light with the frequency f. The second optical modulator 18 modulates the fixed wavelength light with a predetermined frequency f. The second optical modulator 18 generally has lithium niobate (LN), but may not have LN as long as modulation is possible.
[0058]
The coupler 19 makes the combined light obtained by combining the lights output from the first optical modulator 16 and the second optical modulator 18 incident on the DUT 30.
[0059]
The slave device 20 includes a duplexer 21, a first photoelectric converter 22, a second photoelectric converter 24, a phase comparator 26, a characteristic calculation unit 28, and a measurement control unit 29.
[0060]
The demultiplexer 21 demultiplexes the combined light transmitted through the DUT 30 into a fixed wavelength light component and a variable wavelength light component.
[0061]
The first photoelectric converter 22 converts the variable wavelength light component into an electrical signal and outputs an electrical signal for measurement. The second photoelectric converter 24 converts the fixed wavelength light component into an electrical signal and outputs a reference electrical signal.
[0062]
The phase comparator 26 measures the phase of the measurement electric signal with reference to the reference electric signal.
[0063]
The characteristic calculator 28 calculates the group delay characteristic and the chromatic dispersion characteristic of the first optical fiber line 32 based on the phase measured by the phase comparator 26. The group delay characteristic can be calculated from the relationship between the phase measured by the phase comparator 26 and the modulation frequency f. The wavelength dispersion characteristic can be obtained by differentiating the group delay characteristic with respect to the wavelength.
[0064]
The measurement control unit 29 controls the characteristic calculation unit 28 based on the measurement conditions set by the measurement condition setting unit 11 and measures the characteristics of the DUT 30. In addition, the measurement control unit 29 transmits the measurement result of the characteristics of the DUT 30 to the measurement condition setting unit 11.
[0065]
The measurement control communication unit 40 enables communication between the measurement condition setting unit 11 and the measurement control unit 29. Measurement conditions are transmitted from the measurement condition setting unit 11 to the measurement control unit 29 via the measurement control communication unit 40. Further, the measurement result of the characteristics of the DUT 30 is transmitted from the measurement control unit 29 to the measurement condition setting unit 11 via the measurement control communication unit 40. The measurement control communication unit 40 is, for example, one of a wired cable, a wireless communication unit, and a satellite communication unit.
[0066]
Next, the operation of the second embodiment will be described. The operation of the second embodiment is almost the same as the operation of the first embodiment, and will be described with reference to the flowchart of FIG. When the measurement is started, the measurement condition setting unit 11 on the master machine 10 side transmits a first command to the measurement control unit 29 via the measurement control communication unit 40 (S10). The first command is a command for setting measurement conditions.
[0067]
When receiving the first command (S20), the measurement control unit 29 on the slave device 20 side performs initial setting of the slave device 20, various processes, communication error return processing, and the like according to the content of the first command (S21). When the various processes are completed, the measurement control unit 29 transmits a reply command indicating that the various processes are completed to the measurement condition setting unit 11 via the measurement control communication unit 40 (S22).
[0068]
When the measurement condition setting unit 11 receives the reply command (S11), the wavelength of the variable wavelength light source 12 is changed (S12), and the second command is sent from the measurement condition setting unit 11 to the measurement control unit 29 via the measurement control communication unit 40. Transmit (S13). The second command is a signal that the combined light for measurement is incident on the DUT 30. Then, the variable wavelength light source 12 generates variable wavelength light, and the fixed wavelength light source 14 generates fixed wavelength light (S14).
[0069]
The variable wavelength light is modulated by the first optical modulator 16, and the fixed wavelength light is modulated by the second optical modulator 18. The light modulated by the first light modulator 16 and the second light modulator 18 is combined by the coupler 19, and this combined light passes through the DUT 30. The combined light transmitted through the DUT 30 is demultiplexed into a variable wavelength light component and a fixed wavelength light component by the demultiplexer 21. The variable wavelength light component is converted into a measurement electrical signal by the first photoelectric converter 22, and the fixed wavelength light component is converted into a reference electrical signal by the second photoelectric converter 24 and input to the phase comparator 26. The phase comparator 26 measures the phase of the measurement electric signal with reference to the reference electric signal. The characteristic calculator 28 calculates the group delay characteristic and the chromatic dispersion characteristic of the first optical fiber line 32 based on the phase measured by the phase comparator 26. The group delay characteristic can be calculated from the relationship between the phase measured by the phase comparator 26 and the modulation frequency f. The wavelength dispersion characteristic can be obtained by differentiating the group delay characteristic with respect to the wavelength.
[0070]
When the measurement control unit 29 receives the second command (S23), the characteristic calculation unit 28 calculates the characteristic of the DUT 30 (S24). And the measurement control part 29 transmits the measurement result of a characteristic to the measurement condition setting part 11 via the measurement control communication means 40 (S25).
[0071]
When the measurement condition setting unit 11 receives the measurement result (S15), the process returns to the transmission of the first command (S10). Then, the process is terminated by turning off the power of the master machine 10 at an arbitrary time.
[0072]
According to the second embodiment, since communication between the measurement condition setting unit 11 and the measurement control unit 29 can be performed via the measurement control communication unit 40, it is not necessary to newly prepare one fiber pair.
[0073]
Third embodiment
The third embodiment is the same as the second embodiment in that the light is synthesized using a coupler and is incident on the DUT. However, the third embodiment differs from the second embodiment in that the DUT transmits light in both directions. Different. That is, the DUT is an optical fiber that does not have an optical amplifier. In the third embodiment, the DUT 30 and the measurement control communication unit are combined by utilizing the fact that the DUT 30 transmits light in both directions.
[0074]
FIG. 4 shows an optical characteristic measuring apparatus according to the third embodiment of the present invention. The optical characteristic measuring apparatus has a master machine 10 and a slave machine 20. The master machine 10 is connected to one end of the DUT 30, and the slave machine 20 is connected to the other end of the DUT 30.
[0075]
Since the DUT 30 is an optical fiber that does not have an optical amplifier, light is transmitted in both directions. One end side circulator 42 is connected to one end of the DUT 30, and the other end side circulator 44 is connected to the other end.
[0076]
The master machine 10 includes a measurement condition setting unit 11, a variable wavelength light source 12, a fixed wavelength light source 14, optical modulators 16 and 18, and a coupler 19.
[0077]
The measurement condition setting unit 11 is for setting measurement conditions for measuring the characteristics of the DUT 30. The measurement of the characteristics of the DUT 30 is performed by the slave device 20 as will be described later, but the initial setting and communication error recovery processing of the slave device 20 are performed based on the measurement conditions set by the measurement condition setting unit 11. Based on the measurement conditions set by the measurement condition setting unit 11, an optical modulator (not shown) modulates the fixed wavelength light of the fixed wavelength light source (not shown) and enters the DUT 30.
[0078]
The variable wavelength light source 12 generates variable wavelength light whose wavelength can be changed. The variable wavelength light source 12 can sweep the wavelength λx of the variable wavelength light. The first optical modulator 16 modulates variable wavelength light at a predetermined frequency f. The first optical modulator 16 generally has lithium niobate (LN), but may not have LN as long as modulation is possible.
[0079]
The fixed wavelength light source 14 generates fixed wavelength light whose wavelength is fixed at λ0. The second optical modulator 18 modulates the variable wavelength light with the frequency f. The second optical modulator 18 modulates the fixed wavelength light with a predetermined frequency f. The second optical modulator 18 generally has lithium niobate (LN), but may not have LN as long as modulation is possible.
[0080]
The coupler 19 outputs combined light obtained by combining the light output from the first optical modulator 16 and the second optical modulator 18. The combined light is combined with measurement condition light that is emitted from the measurement control unit 11 and indicates measurement conditions, and is incident on one end of the DUT 30.
[0081]
The one-end-side circulator 42 has a first terminal 42a, a second terminal 42b, and a third terminal 42c. The first terminal 42a receives synthesized light or light (measurement condition light or the like) output from the measurement condition setting unit 11. The second terminal 42b outputs light received by the first terminal 42a and receives light input. The third terminal 42c outputs the light received by the second terminal 42b. The second terminal 42 b is connected to one end of the DUT 30, and the third terminal 42 c is connected to the measurement condition setting unit 11.
[0082]
The slave device 20 includes a duplexer 21, a first photoelectric converter 22, a second photoelectric converter 24, a phase comparator 26, a characteristic calculation unit 28, and a measurement control unit 29.
[0083]
The demultiplexer 21 demultiplexes the combined light transmitted through the DUT 30 into a fixed wavelength light component, a variable wavelength light component, and a measurement condition light component.
[0084]
The first photoelectric converter 22 converts the variable wavelength light component into an electrical signal and outputs an electrical signal for measurement. The second photoelectric converter 24 converts the fixed wavelength light component into an electrical signal and outputs a reference electrical signal.
[0085]
The phase comparator 26 measures the phase of the measurement electric signal with reference to the reference electric signal.
[0086]
The characteristic calculator 28 calculates the group delay characteristic and the chromatic dispersion characteristic of the first optical fiber line 32 based on the phase measured by the phase comparator 26. The group delay characteristic can be calculated from the relationship between the phase measured by the phase comparator 26 and the modulation frequency f. The wavelength dispersion characteristic can be obtained by differentiating the group delay characteristic with respect to the wavelength.
[0087]
The measurement control unit 29 controls the characteristic calculation unit 28 based on the measurement conditions set by the measurement condition setting unit 11 and measures the characteristics of the DUT 30. The measurement control unit 29 receives the measurement condition light component from the duplexer 21 and acquires the measurement condition. In addition, the measurement control unit 29 transmits the measurement result and the like to the optical modulator 54. Therefore, the optical modulator 54 modulates the fixed wavelength light generated by the fixed wavelength light source 52 based on the measurement result or the like, thereby transmitting the measurement result or the like to the measurement control unit 11.
[0088]
The other end side circulator 44 has a first terminal 44a, a second terminal 44b, and a third terminal 44c. The first terminal 44 a receives fixed wavelength light indicating a measurement result generated by the fixed wavelength light source 52. The second terminal 44b outputs light received by the first terminal 44a and receives light input. The third terminal 44c outputs the light received by the second terminal 44b. The second terminal 44 b is connected to the other end of the DUT 30, and the third terminal 44 c is connected to the duplexer 21.
[0089]
Next, the operation of the third embodiment will be described. The operation of the third embodiment is almost the same as the operation of the first embodiment, and will be described with reference to the flowchart of FIG. When the measurement is started, the measurement condition setting unit 11 on the master machine 10 side transmits a fast command to the measurement control unit 29 via the one end side circulator 42, the DUT 30 and the other end side circulator 44 (S10). More specifically, the measurement condition setting unit 11 generates light indicating the measurement condition and enters the first terminal 42 a of the one-end-side circulator 42. The light incident on the first terminal 42 a is output from the second terminal 42 b and passes through the DUT 30. The light passes through the DUT 30 and enters the second terminal 44 b of the circulator 44 on the other end side. The light incident on the second terminal 44b is output from the third terminal 44c. The measurement condition light output from the third terminal 44 c is transmitted to the measurement control unit 29 via the duplexer 21. However, the first command is a command for setting measurement conditions.
[0090]
When receiving the first command (S20), the measurement control unit 29 on the slave device 20 side performs initial setting of the slave device 20, various processes, communication error return processing, and the like according to the content of the first command (S21). When the various processes are completed, the measurement control unit 29 transmits a reply command indicating that the various processes are completed to the measurement condition setting unit 11 via the other end side circulator 44, the DUT 30, and the one end side circulator 42 (S22). . More specifically, the fixed wavelength light generated by the fixed wavelength light source 52 is modulated by the optical modulator 54. The measurement control unit 29 controls the optical modulator 54 so that the fixed wavelength light generated by the fixed wavelength light source 52 is incident on the first terminal 44a of the other-end circulator 44 so as to indicate a reply command. The light incident on the first terminal 44a is output from the second terminal 44b. The light output from the second terminal 44 b passes through the DUT 30 and is incident on the second terminal 42 b of the one-end circulator 42. The light incident on the second terminal 42b is output from the third terminal 42c. The measurement result light output from the third terminal 42 c is transmitted to the measurement condition setting unit 11.
[0091]
When the measurement condition setting unit 11 receives the reply command (S11), the wavelength of the variable wavelength light source 12 is changed (S12), and the second command is sent from the measurement condition setting unit 11 to the one end side circulator 42, the DUT 30 and the other end side circulator 44. To the measurement control unit 29 (S13). However, the second command is a signal that the combined light for measurement is incident on the DUT 30. Then, the variable wavelength light source 12 generates variable wavelength light, and the fixed wavelength light source 14 generates fixed wavelength light (S14).
[0092]
The variable wavelength light is modulated by the first optical modulator 16, and the fixed wavelength light is modulated by the second optical modulator 18. The light modulated by the first light modulator 16 and the second light modulator 18 is combined by the coupler 19, and this combined light passes through the DUT 30. The combined light transmitted through the DUT 30 is demultiplexed into a variable wavelength light component and a fixed wavelength light component by the demultiplexer 21. The variable wavelength light component is converted into a measurement electrical signal by the first photoelectric converter 22, and the fixed wavelength light component is converted into a reference electrical signal by the second photoelectric converter 24 and input to the phase comparator 26. The phase comparator 26 measures the phase of the measurement electric signal with reference to the reference electric signal. The characteristic calculator 28 calculates the group delay characteristic and the chromatic dispersion characteristic of the first optical fiber line 32 based on the phase measured by the phase comparator 26. The group delay characteristic can be calculated from the relationship between the phase measured by the phase comparator 26 and the modulation frequency f. The wavelength dispersion characteristic can be obtained by differentiating the group delay characteristic with respect to the wavelength.
[0093]
When the measurement control unit 29 receives the second command (S23), the characteristic calculation unit 28 calculates the characteristic of the DUT 30 (S24). And the measurement control part 29 transmits the measurement result of a characteristic to the measurement condition setting part 11 via the other end side circulator 44, DUT30, and the one end side circulator 42 (S25).
[0094]
When the measurement condition setting unit 11 receives the measurement result (S15), the process returns to the transmission of the first command (S10). Then, the process is terminated by turning off the power of the master machine 10 at an arbitrary time.
[0095]
According to the third embodiment, since the DUT 30 transmits light in both directions, the communication between the measurement condition setting unit 11 and the measurement control unit 29 can be performed via the DUT 30, so it is necessary to newly prepare one fiber pair. Absent.
[0096]
Moreover, said embodiment is realizable as follows. A medium having a CPU, a hard disk, and a medium (floppy disk, CD-ROM, etc.) reading device is read by a computer having a program that realizes each of the above components, and installed on the hard disk. Such a method can also realize the above functions.
[0097]
【The invention's effect】
According to the present invention, the chromatic dispersion characteristic can be measured without requiring one fiber pair in addition to the DUT.
[Brief description of the drawings]
FIG. 1 is a block diagram showing an optical characteristic measuring apparatus according to a first embodiment of the present invention.
FIG. 2 is a flowchart showing the operation of the first embodiment of the present invention.
FIG. 3 is a block diagram showing an optical characteristic measuring apparatus according to a second embodiment of the present invention.
FIG. 4 is a block diagram showing an optical characteristic measuring apparatus according to a third embodiment of the present invention.
FIG. 5 is a block diagram showing the configuration of a measurement system for optical dispersion when one fiber pair in the prior art is a DUT.
[Explanation of symbols]
10 Master machine
11 Measurement condition setting section
12 Variable wavelength light source
14 Fixed wavelength light source
16, 18 Optical modulator
19 Coupler
20 Slave machine
22 First photoelectric converter
24 Second photoelectric converter
26 Phase comparator
28 Characteristic calculator
29 Measurement controller
30 DUT
42 One end side circulator
42a First terminal
42b Second terminal
42c 3rd terminal
44 circulator at the other end
44a First terminal
44b Second terminal
44c 3rd terminal

Claims (10)

An apparatus for measuring characteristics of an object to be measured that transmits light,
Measurement condition setting means for setting measurement conditions for measuring characteristics of the object to be measured;
Light generating means for generating variable wavelength light and fixed wavelength light;
Characteristic measuring means for measuring characteristics of the object to be measured based on the variable wavelength light and the fixed wavelength light transmitted through the object to be measured;
Measurement control means for controlling the characteristic measurement means based on the measurement conditions;
A measurement control communication means for transmitting the measurement conditions to the measurement control means and transmitting the measurement results to the measurement condition setting means;
With
The object to be measured passes light in both directions,
The variable wavelength light and the fixed wavelength light are combined and transmitted through the object to be measured;
The measurement control communication means is common to the object to be measured.
Optical property measuring device. A light generating device used in a device for measuring characteristics of an object to be measured that transmits light,
Measurement condition setting means for setting measurement conditions for measuring characteristics of the object to be measured;
Light generating means for generating variable wavelength light and fixed wavelength light;
A measurement control communication means for transmitting the measurement condition from the measurement condition setting means and transmitting a measurement result of the object to be measured to the measurement condition setting means;
With
The object to be measured passes light in both directions,
The variable wavelength light and the fixed wavelength light are combined and transmitted through the object to be measured;
The measurement control communication means is common to the object to be measured.
Light generator. An apparatus for measuring characteristics of an object to be measured that transmits light,
Characteristic measuring means for measuring the characteristic of the object to be measured based on the variable wavelength light and the fixed wavelength light transmitted through the object to be measured;
Measurement control means for controlling the characteristic measurement means based on measurement conditions;
A measurement control communication means for transmitting the measurement conditions to the measurement control means and transmitting a measurement result of the characteristics of the device under test from the measurement control means;
With
The object to be measured passes light in both directions,
The variable wavelength light and the fixed wavelength light are combined and transmitted through the object to be measured;
The measurement control communication means is common to the object to be measured.
Optical property measuring device. A first terminal that receives combined light in which the variable wavelength light and the fixed wavelength light are combined, a second terminal that outputs light received by the first terminal and receives light input, and the second terminal receives light. And a third terminal for outputting light, wherein the second terminal is connected to one end of the object to be measured, and the one end side circulator is connected to the measurement condition setting means,
A first terminal that receives the measurement result; a second terminal that outputs light received by the first terminal and receives light; and a third terminal that outputs light received by the second terminal. The second terminal is connected to the other end of the object to be measured, and the third terminal is connected to the measurement control means, and the other end side circulator;
The optical characteristic measuring device according to claim 1, comprising: A method for measuring characteristics of an object to be measured that transmits light,
A measurement condition setting step for setting measurement conditions for measuring characteristics of the object to be measured;
A light generation step for generating variable wavelength light and fixed wavelength light;
A characteristic measuring step for measuring characteristics of the measurement object based on the variable wavelength light and the fixed wavelength light transmitted through the measurement object;
A measurement control step for controlling the characteristic measurement step based on the measurement conditions;
A measurement control communication step for transmitting the measurement conditions to a measurement control unit for performing the measurement control step, and transmitting the measurement results to a measurement condition setting means for performing the measurement condition setting step;
With
The object to be measured passes light in both directions,
The variable wavelength light and the fixed wavelength light are combined and transmitted through the object to be measured;
The measurement control communication means for performing the measurement control communication step is common to the device under test.
Optical property measurement method. A light generation method used for measuring characteristics of an object to be measured that transmits light,
A measurement condition setting step for setting measurement conditions for measuring characteristics of the object to be measured;
A light generation step for generating variable wavelength light and fixed wavelength light;
A measurement control communication step for transmitting the measurement condition from a measurement condition setting unit for performing the measurement condition setting step, and transmitting a measurement result of the object to be measured to a measurement condition setting unit for performing the measurement condition setting step;
With
The object to be measured passes light in both directions,
The variable wavelength light and the fixed wavelength light are combined and transmitted through the object to be measured;
The measurement control communication means for performing the measurement control communication step is common to the device under test.
Light generation method. A method for measuring characteristics of an object to be measured that transmits light,
A characteristic measuring step of measuring the characteristic of the object to be measured based on the variable wavelength light and the fixed wavelength light transmitted through the object to be measured;
A measurement control step for controlling the characteristic measurement step based on measurement conditions;
A measurement control communication step for transmitting the measurement conditions to a measurement control means for performing the measurement control step, and transmitting a measurement result of the characteristic of the object to be measured from the measurement control means for performing the measurement control step;
With
The object to be measured passes light in both directions,
The variable wavelength light and the fixed wavelength light are combined and transmitted through the object to be measured;
The measurement control communication means for performing the measurement control communication step is common to the device under test.
Optical property measurement method. A computer-readable recording medium storing a program for causing a computer to execute a light generation process used in a process for measuring characteristics of an object to be measured that transmits light,
A measurement condition setting process for setting measurement conditions for measuring characteristics of the object to be measured;
Light generation processing for generating variable wavelength light and fixed wavelength light;
A characteristic measurement process for measuring the characteristic of the measurement object based on the variable wavelength light and the fixed wavelength light transmitted through the measurement object;
A measurement control process for controlling the characteristic measurement process based on the measurement conditions;
A measurement control communication process for transmitting the measurement condition to a measurement control unit for performing the measurement control process, and transmitting the measurement result to a measurement condition setting unit for performing the measurement condition setting process;
A recording medium readable by the recording a computer program for causing a computer to execute the,
The object to be measured passes light in both directions,
The variable wavelength light and the fixed wavelength light are combined and transmitted through the object to be measured;
The measurement control communication means for performing the measurement control communication process is common to the device under test.
Recording medium . A computer-readable recording medium recording a program for causing a computer to execute a light generation process used in a light generation process used for measuring characteristics of an object to pass light,
A measurement condition setting process for setting measurement conditions for measuring characteristics of the object to be measured;
Light generation processing for generating variable wavelength light and fixed wavelength light;
A measurement control communication process for transmitting the measurement condition from a measurement condition setting unit for performing the measurement condition setting process, and transmitting a measurement result of the object to be measured to a measurement condition setting unit for performing the measurement condition setting process;
A recording medium readable by the recording a computer program for causing a computer to execute the,
The object to be measured passes light in both directions,
The variable wavelength light and the fixed wavelength light are combined and transmitted through the object to be measured;
The measurement control communication means for performing the measurement control communication process is common to the device under test.
Recording medium . A computer-readable recording medium storing a program for causing a computer to execute a light generation process used in a process for measuring characteristics of an object to be measured that transmits light,
A characteristic measurement process for measuring characteristics of the measurement object based on variable wavelength light and fixed wavelength light transmitted through the measurement object;
A measurement control process for controlling the characteristic measurement process based on measurement conditions;
A measurement control communication process for transmitting the measurement conditions to a measurement control means for performing the measurement control process, and transmitting a measurement result of the characteristic of the object to be measured from the measurement control means for performing the measurement control process;
A recording medium readable by the recording a computer program for causing a computer to execute the,
The object to be measured passes light in both directions,
The variable wavelength light and the fixed wavelength light are combined and transmitted through the object to be measured;
The measurement control communication means for performing the measurement control communication process is common to the device under test.
Recording medium .

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