JP2015115863A - Optical transmission device, optical transmission system, and optical transmission method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an optical transmission device, an optical transmission system, and an optical transmission method capable of suppressing the occurrence of a largely-scaled line failure by early finding out the occurrence of the failure of a transmission device or the abnormality of a transmission line to execute preventive maintenance.SOLUTION: A reception device 1 detects the occurrence of the failure of a reception device 1, the failure of a transmission device 2 and the abnormality of a transmission line 3 by using the value of the dispersion compensation amount of a variable dispersion compensation part 103, and notifies a monitoring control device 4 of the occurrence of the failure and failure. The monitoring control device 4 displays notification from the reception device 1, and executes switching processing of switching the reception device 1 to a preliminarily reception device 5, switching processing of switching the transmission device 2 to a preliminarily transmission device 6 and the automatic restoration processing of the reception device 1 and the transmission device 2.

Description

  The present invention relates to an optical transmission apparatus, an optical transmission system, and an optical transmission method having a variable dispersion compensation function.

Conventionally, wavelength division multiplexing optical transmission systems have been used. The transmission device outputs an optical signal in which a data signal is superimposed on light of a plurality of different wavelengths including a predetermined center wavelength.
The output optical signal is transmitted to the receiving device via a transmission path composed of an optical fiber.

  In general, an optical fiber has a characteristic that a propagation speed varies depending on a wavelength of propagating light. That is, light having a short wavelength has a high propagation speed in the optical fiber, and light having a long wavelength has a low propagation speed in the optical fiber. Therefore, the optical signals simultaneously output from the transmission device have a time difference in reaching the reception device according to the wavelength. Thus, the delay difference of the optical signal generated in the transmission line depending on the wavelength is referred to as “wavelength dispersion”. In an optical transmission system, a signal waveform deteriorates due to chromatic dispersion.

  An optical transmission system with a low communication speed has high dispersion tolerance against chromatic dispersion, and the influence of signal waveform degradation caused by chromatic dispersion is small. On the other hand, an optical transmission system with a high communication speed has low dispersion tolerance, and the influence of signal waveform deterioration becomes large.

In recent years, with an increase in communication data capacity, there has been a demand for an increase in transmission capacity of optical transmission systems. The transmission capacity of the optical transmission system depends on the transmission speed per wavelength of the optical signal.
The transmission speed per wavelength is increased from 1 gigabit per second (Gbps) to 10 Gbps, 40 Gbps, and 100 Gbps. In particular, a dispersion compensation function is indispensable because the dispersion tolerance becomes low at a transmission rate of 40 Gbps or more.

  There are two types of dispersion compensation functions: compensation using a dispersion compensation fiber or the like with a fixed amount of dispersion compensation, and compensation using a variable dispersion compensator or the like while varying the dispersion compensation amount. In communication apparatuses having a transmission rate of 40 Gbps or more, dispersion compensation with higher accuracy is required, and therefore a variable dispersion compensation function is generally used (see, for example, Patent Document 1).

  In addition, as the transmission speed per wavelength increases, the influence of transmission device failures and transmission line abnormalities also increases. Therefore, there is a need for a means for detecting a failure or abnormality before a complete line disconnection and performing preventive maintenance to prevent a large-scale line failure from occurring. As a means of preventive maintenance, conventionally used is a method of monitoring the bit error rate (BER) value of a data signal and notifying the outside when the transmission performance deteriorates and the BER value becomes large. It has been.

JP 2010-278562 A

  An optical transmission system having a variable dispersion compensation function performs dispersion compensation while varying the compensation amount according to the chromatic dispersion amount. Therefore, the BER value of the data signal may not fluctuate even when the chromatic dispersion amount increases or decreases due to a failure of the transmission device or an abnormality of the transmission path. As a result, there has been a problem that the operation is continued without notifying the failure of the transmission apparatus or the abnormality of the transmission path, and a large-scale line failure is caused due to a sudden line disconnection.

  The present invention was made to solve the above-described problems, and by detecting a failure of a transmission device or an abnormality of a transmission line at an early stage and carrying out preventive maintenance, a large-scale line failure An object of the present invention is to provide an optical transmission device, an optical transmission system, and an optical transmission method that can suppress the occurrence of the above.

  An optical transmission apparatus according to the present invention includes a variable dispersion compensator that compensates for a delay difference of an optical signal generated in a transmission line, and a compensation for the optical signal of the variable dispersion compensator according to an error correction value of a data signal obtained from the optical signal. A dispersion compensation amount setting unit that sets the amount, and a dispersion compensation amount monitoring unit that detects a failure of the optical transmission apparatus main body or an abnormality in the transmission path using the compensation amount and notifies the occurrence of the failure or the abnormality to the outside. It has.

  According to the optical transmission device, the optical transmission system, and the optical transmission method of the present invention, the occurrence of a large-scale line failure can be realized by detecting a failure of the transmission device or the occurrence of an abnormality in the transmission line at an early stage and performing preventive maintenance. Can be suppressed.

It is a block diagram of the optical transmission system of Embodiment 1 of this invention. It is a flowchart which shows operation | movement of the optical transmission system of Embodiment 1 of this invention. It is a block diagram of the optical transmission system of Embodiment 2 of this invention. It is a block diagram of the optical transmission system of Embodiment 3 of this invention.

Embodiment 1 FIG.
The optical transmission system according to the first embodiment will be described with reference to FIG.
In the figure, 201 is a transmission data generation unit. The transmission data generation unit 201 is provided on the interface board 21 of the transmission device (optical transmission device) 2. The transmission data generation unit 201 generates an optical signal in which a data signal is superimposed on light of a plurality of different wavelengths including a predetermined center wavelength. The transmission data generation unit 201 outputs the generated optical signal to the intra-device fiber 12 of the reception device (optical transmission device) 1 via the transmission path 3 configured with an optical fiber.

  The in-device fiber 12 is composed of a dispersion compensating fiber having a chromatic dispersion characteristic opposite to the chromatic dispersion characteristic of the optical fiber constituting the transmission path 3. In this way, the signal waveform deterioration due to the wavelength dispersion is compensated by compensating for the delay difference (hereinafter referred to as “wavelength dispersion”) of the optical signal generated in the transmission line 3 depending on the wavelength. The optical signal that has passed through the in-device fiber 12 is output to the tunable dispersion compensator 103.

  The tunable dispersion compensator 103 is composed of a tunable dispersion compensator or a large scale integrated circuit (Large Scale Integration, LSI) having a tunable dispersion compensation function. Ideally, the chromatic dispersion of the optical signal that has passed through the in-device fiber 12 is desirably 0, but in practice, a certain amount of dispersion often remains (hereinafter referred to as “residual dispersion”). The tunable dispersion compensator 103 compensates for signal waveform degradation due to residual dispersion by compensating the residual dispersion with a set dispersion compensation amount. The tunable dispersion compensator 103 outputs an optical signal compensated for the residual dispersion to the reception data extraction unit 102.

  The reception data extraction unit 102 extracts a data signal from the optical signal and outputs a data signal obtained from the optical signal to the error correction unit 101.

  The error correction unit 101 executes error correction processing of the data signal, and performs dispersion compensation on the value of the number of errors of the corrected data signal or the bit error rate (BER) of the data signal (hereinafter referred to as “error correction value”). The data is output to the amount setting unit 104.

  The dispersion compensation amount setting unit 104 sets the dispersion compensation amount value of the tunable dispersion compensation unit 103 to an appropriate value so that the error correction value becomes smaller. The set dispersion compensation amount (correction compensation amount) value is output to the dispersion compensation amount monitoring unit 105.

  The dispersion compensation amount monitoring unit 105 uses the set dispersion compensation amount (correction compensation amount) value to detect the failure of the receiving device 1, the failure of the transmitting device 2, and the occurrence of an abnormality in the transmission path 3, and the failure. The occurrence of an abnormality is notified to the monitoring control device 4.

  Here, the error correction unit 101, the reception data extraction unit 102, the tunable dispersion compensation unit 103, the dispersion compensation amount setting unit 104, and the dispersion compensation amount monitoring unit 105 are provided on the interface board 11 of the reception device 1.

  A spare receiving device (standby optical transmission device) 5 having the same configuration as that of the receiving device 1 is provided so as to be connectable to the transmission path 3. A standby transmission device (backup optical transmission device) 6 having the same configuration as that of the transmission device 2 is provided so as to be connectable to the transmission path 3.

The monitoring control device 4 has a display output unit such as a liquid crystal display (not shown), and displays a notification from the dispersion compensation amount monitoring unit 105.
In addition, the monitoring control device 4 has an operation input unit such as a touch panel (not shown). Accordingly, whether or not the switching process from the failed receiving apparatus 1 to the standby receiving apparatus 5 and the switching process from the failed transmitting apparatus 2 to the standby transmitting apparatus 6 can be executed, and the automatic recovery process of the failed receiving apparatus 1 and transmitting apparatus 2 Whether to execute or not is set. In addition, the execution time of the automatic recovery process is set.

  The redundant configuration optical transmission system 300 is configured by the reception device 1, the transmission device 2, the transmission line 3, the monitoring control device 4, the standby reception device 5, and the backup transmission device 6 configured as described above.

Next, the operation of the optical transmission system 300 will be described.
First, the dispersion compensation amount monitoring unit 105 uses the detection method of at least one of the following three detection methods to detect a failure of the reception device 1, a failure of the transmission device 2, and an abnormality of the transmission path 3. To detect.

(First detection method)
When the dispersion amount of the chromatic dispersion of the optical signal generated in the transmission line 3 and the dispersion amount of the residual dispersion of the optical signal after passing through the in-device fiber 12 are known in advance, the threshold value for determining normality, failure and abnormality A threshold value for determining that the occurrence has occurred is set in advance. The dispersion compensation amount monitoring unit 105 detects the occurrence of a failure or abnormality by comparing the dispersion compensation amount value of the tunable dispersion compensation unit 103 with a set threshold value.

(Second detection method)
When the dispersion amount of the chromatic dispersion of the optical signal generated in the transmission line 3 and the dispersion amount of the residual dispersion of the optical signal after passing through the in-device fiber 12 are unknown, the variation of the dispersion compensation amount is used. The dispersion compensation amount monitoring unit 105 holds the value of the dispersion compensation amount when the dispersion compensation amount of the tunable dispersion compensation unit 103 does not change or becomes a certain value or less as a normal value. When the dispersion compensation value fluctuates from a normal value by a certain range or more, the occurrence of a failure or abnormality is detected.

(Third detection method)
In addition to the dispersion compensation amount variation, the variation of the BER value of the data signal and the variation of the reception level value of the optical signal are used. The dispersion compensation amount monitoring unit 105 holds normal values similar to those in the second detection method with respect to fluctuations in the BER and the reception level, and detects occurrence of failure and abnormality when the fluctuations exceed a certain range from the normal values.

FIG. 2 is a flowchart illustrating the operation of the optical transmission system 300 when the dispersion compensation amount monitoring unit 105 detects the occurrence of a failure or abnormality.
When the dispersion compensation amount monitoring unit 105 detects the failure of the reception device 1, the failure of the transmission device 2, and the occurrence of an abnormality in the transmission path 3 using any one of the first detection method to the third detection method, The occurrence of abnormality is notified to the monitoring control device 4 (step ST1).

The monitoring control device 4 displays the notification from the dispersion compensation amount monitoring unit 105 (step ST2).
Next, it is confirmed whether or not the automatic recovery process can be executed (step ST3). When the execution of the automatic recovery process is rejected (NO in step ST3), the monitoring control device 4 ends the process. On the other hand, when the execution of the automatic recovery process is permitted (YES in step ST3), the monitoring control device 4 checks whether or not the current time is the preset execution time of the automatic recovery process (step ST4).

When the current time is the execution time of the automatic recovery process (YES in step ST4), the monitoring control device 4 confirms whether or not the switching process can be executed (step ST5). On the other hand, when the current time is different from the execution time of the automatic recovery process (NO in step ST4), the monitoring control device 4 waits until the execution time of the automatic recovery process is reached.
At this time, by setting the execution time of the automatic recovery process to the time of the night time zone when the amount of traffic (traffic) is small, the influence of line disconnection due to the recovery process can be minimized.

When the optical transmission system 300 has a redundant configuration including the standby receiving device 5 and the standby transmitting device 6 and permits execution of the switching process (YES in step ST5), the supervisory control device 4 determines that the receiving device has failed. At least one of a switching process for switching 1 to the spare receiving apparatus 5 and a switching process for switching the failed transmitting apparatus 2 to the spare transmitting apparatus 6 is executed (step ST6).
Thus, by performing the switching process as a redundant configuration, the line disconnection time associated with the recovery process can be minimized.

  On the other hand, if the optical transmission system 300 does not have a redundant configuration or if the execution of the switching process is rejected (NO in step ST5), the monitoring control device 4 skips the switching process.

  Next, the monitoring control device 4 executes automatic recovery processing for the receiving device 1 and the transmitting device 2 (step ST7). The receiving device 1 and the transmitting device 2 attempt to recover autonomously by resetting some functions, resetting some functions, or resetting the entire device.

As described above, the receiving device 1 according to the first embodiment uses the dispersion compensation amount value of the tunable dispersion compensator 103 to detect a failure of the receiving device 1, a failure of the transmitting device 2, and an abnormality of the transmission path 3. At the same time, the monitoring and control device 4 is notified of the occurrence of failure and abnormality. In addition, the monitoring control device 4 displays a notification from the receiving device 1 and also performs switching processing for switching the receiving device 1 to the standby receiving device 5, switching processing for switching the transmitting device 2 to the standby transmitting device 6, and the receiving device 1 and The automatic recovery process of the transmission device 2 is executed.
In this way, the occurrence of a large-scale line failure can be suppressed by detecting the occurrence of a failure of the transmission device or the occurrence of an abnormality in the transmission line at an early stage and performing preventive maintenance.

  Note that the tunable dispersion compensator 103 may be configured by an LSI having a function of autonomously estimating an appropriate dispersion compensation value. The dispersion compensation amount monitoring unit 105 uses a value of the estimated dispersion compensation amount estimated by the LSI in place of the dispersion compensation amount value set by the dispersion compensation amount setting unit 104 to cause a failure in the reception device 1 or a failure in the transmission device 2. The occurrence of an abnormality in the transmission path 3 may be detected.

  Further, the dispersion compensation amount monitoring unit 105 may be configured to detect at least one of a failure of the reception device 1, a failure of the transmission device 2, or an abnormality of the transmission path 3. The monitoring control device 4 also performs switching processing for switching the receiving device 1 to the standby receiving device 5, switching processing for switching the transmitting device 2 to the standby transmitting device 6, automatic recovery processing for the receiving device 1, or automatic recovery processing for the transmitting device 2. It is good also as a structure which performs at least 1 of these.

  Moreover, the structure of the display output part of the monitoring control apparatus 4 is not limited to a liquid crystal display. It may be provided with a cathode ray tube display, or may be provided with a speaker and outputting a voice notification. Furthermore, the configuration of the operation input unit is not limited to the touch panel, and may include a touch key or an operation lever.

Embodiment 2. FIG.
With reference to FIG. 3, an optical transmission system in which a monitoring control device is connected to a transmission device will be described. In addition, the same code | symbol is attached | subjected to the structural member similar to the optical transmission system 300 of Embodiment 1 shown in FIG. 1, and description is abbreviate | omitted.

  In the figure, reference numeral 106 denotes a compensation data notification unit. The compensation data notification unit 106 is provided on the interface board 11 of the receiving device 1. Further, the compensation data notification unit 106 acquires the value of the dispersion compensation amount set by the dispersion compensation amount setting unit 104, and sends the acquired value to the variable dispersion compensation unit 202 provided on the interface board 21 of the transmission device 2. It comes to notify.

The tunable dispersion compensator 202 is interposed between the transmission data generator 201 and the transmission path 3.
The tunable dispersion compensator 202 has the same configuration as that of the tunable dispersion compensator 103 according to Embodiment 1, and compensates for residual dispersion that cannot be compensated for by the in-device fiber 12 of the receiving device 1. Is compensated with the amount of dispersion compensation notified from. A dispersion compensation amount monitoring unit 203 provided on the interface board 21 is connected to the variable dispersion compensation unit 202.

  The dispersion compensation amount monitoring unit 203 has a configuration similar to that of the dispersion compensation amount monitoring unit 105 of the first embodiment, and a failure or transmission of the reception apparatus 1 is detected using the dispersion compensation amount value of the variable dispersion compensation unit 202. The failure of the device 2 and the occurrence of an abnormality in the transmission path 3 are detected. In addition, the monitoring control device 4 is connected to the dispersion compensation amount monitoring unit 203.

The optical transmission system 301 configured as described above operates in the same manner as the optical transmission system 300 according to the first embodiment as follows.
That is, the transmission device 2 detects a failure of the reception device 1, a failure of the transmission device 2, and an occurrence of an abnormality in the transmission path 3 using any one of the first detection method to the third detection method. The monitoring control device 4 is notified of the occurrence of an abnormality. In addition, the monitoring control device 4 displays a notification from the transmission device 2, and also performs switching processing for switching the reception device 1 to the standby reception device 5, switching processing for switching the transmission device 2 to the standby transmission device 6, and the reception device 1 and The automatic recovery process of the transmission device 2 is executed.
In this way, the occurrence of a large-scale line failure can be suppressed by detecting the occurrence of a failure of the transmission device or the occurrence of an abnormality in the transmission line at an early stage and performing preventive maintenance.

Embodiment 3 FIG.
With reference to FIG. 4, an optical transmission system in which a receiving device is provided with a plurality of interface boards will be described. In addition, the same code | symbol is attached | subjected to the structural member similar to the optical transmission system 300 of Embodiment 1 shown in FIG. 1, and description is abbreviate | omitted.

  In the figure, reference numeral 13 denotes a wavelength separation unit. The wavelength demultiplexing unit 13 demultiplexes the wavelength-multiplexed optical signal received from the transmission device 2 via the transmission path 3 and the intra-device fiber 12 for each wavelength. The optical signals separated by the wavelength separation unit 13 are, according to the respective wavelengths, a first variable dispersion compensation unit 103a provided on the first interface substrate 11a, a second variable dispersion compensation unit 103b provided on the second interface substrate 11b, And the third variable dispersion compensator 103c provided on the third interface board 11c.

  The first interface board 11a is provided with a first reception data extraction unit 102a having the same configuration as the reception data extraction unit 102 of the first embodiment. Similarly, a first error correction unit 101a and a first dispersion compensation amount setting unit 104a are provided.

  Between the first variable dispersion compensator 103a and the monitoring controller 4a so as to notify the monitoring controller 4a of the value of the dispersion compensation amount of the first variable dispersion compensator 103a set by the first dispersion compensation amount setting unit 104a. The first dispersion compensation amount notification unit 107a is interposed.

  The second interface board 11b has the same configuration as the first interface board 11a. A second dispersion compensation amount notification unit 107b is interposed between the second variable dispersion compensation unit 103b and the monitoring control device 4a so as to notify the monitoring control device 4a of the value of the dispersion compensation amount of the second variable dispersion compensation unit 103b. ing.

  The third interface board 11c has the same configuration as the first interface board 11a. A third dispersion compensation amount notification unit 107c is interposed between the third variable dispersion compensation unit 103c and the monitoring control device 4a so as to notify the monitoring control device 4a of the value of the dispersion compensation amount of the third variable dispersion compensation unit 103c. ing.

The monitoring control device 4a uses the dispersion compensation amount values notified from the first dispersion compensation amount notification unit 107a to the third dispersion compensation amount notification unit 107c, respectively, to each of the first interface board 11a to the third interface board 11c. This is to detect a failure.
The monitoring control device 4a has a display output unit such as a display (not shown), and displays the occurrence of the detected failure. Further, the monitoring control device 4a has an operation input unit such as a touch panel (not shown), and sets a value of an allowable difference value used for detecting a failure.

An operation of the optical transmission system 302 configured as described above will be described.
The monitoring control device 4a calculates the average value of the dispersion compensation amount values respectively notified from the first dispersion compensation amount notification unit 107a to the third dispersion compensation amount notification unit 107c. Next, a difference value between the value notified from each of the first dispersion compensation amount notification unit 107a to the third dispersion compensation amount notification unit 107c and the calculated average value is calculated, and this difference value and a preset difference allowable value are calculated. And compare.

At this time, since the first interface board 11a to the third interface board 11c all receive the optical signal via the same transmission path 3, the first variable dispersion compensator 103a to the third variable dispersion are in a normal state. The value of the dispersion compensation amount of the compensation unit 103c is the same value.
Therefore, when the calculated difference value becomes larger than the allowable difference value, the monitoring control device 4a detects the occurrence of a failure in the corresponding first interface board 11a to third interface board 11c.

As described above, the receiving device 1 according to the third embodiment includes the first interface board 11a to the third interface board 11c. In addition, the monitoring control device 4a uses the dispersion compensation amount values notified from the first dispersion compensation amount notification unit 107a to the third dispersion compensation amount notification unit 107c, respectively, to perform the first interface substrate 11a to the third interface substrate 11c. Each fault is detected and displayed.
In this way, the occurrence of a large-scale line failure can be suppressed by detecting the occurrence of a failure in each interface board of the transmission apparatus at an early stage.

  Although FIG. 4 shows a configuration in which the receiving apparatus 1 includes the first interface board 11a to the third interface board 11c, the number of interface boards is not limited to three. Any number of interface boards may be used depending on the wavelength of the multiplexed light.

  Similarly to the dispersion compensation amount monitoring unit 105 of the first embodiment, the monitoring control device 4a uses any one of the first detection method to the third detection method to detect a failure of the reception device 1 and the transmission device 2. It is also possible to detect the occurrence of a failure and an abnormality in the transmission line 3.

Further, as in the first embodiment, a spare receiving apparatus having the same configuration as the receiving apparatus 1 and a spare transmitting apparatus having the same configuration as the transmitting apparatus 2 may be provided. Similarly to the monitoring control device 4 of the first embodiment, the monitoring control device 4a displays the notification from the transmission device 2, and performs switching processing for switching the reception device 1 to the standby reception device 5, and the transmission device 2 as the standby transmission device. The switching process to switch to 6 and the automatic restoration process of the receiving device 1 and the transmitting device 2 are executed.
In this way, the occurrence of a large-scale line failure can be suppressed by early detection of the failure of the transmission device, the failure of each interface board, and the occurrence of the abnormality of the transmission path and the implementation of the preventive maintenance.

  In the present invention, within the scope of the invention, any combination of the embodiments, or any modification of any component in each embodiment, or omission of any component in each embodiment is possible. .

  DESCRIPTION OF SYMBOLS 1 Receiving device (optical transmission device), 2 Transmitting device (optical transmission device), 3 Transmission path, 4 and 4a Monitoring and control device, 5 Standby receiving device (backup optical transmission device), 6 Standby transmission device (backup optical transmission device) 11 interface board, 11a first interface board, 11b second interface board, 11c third interface board, 12 in-device fiber, 13 wavelength separation unit, 21 interface board, 101 error correction unit, 101a first error correction unit, 101b Second error correction unit, 101c Third error correction unit, 102 received data extraction unit, 102a first received data extraction unit, 102b second received data extraction unit, 102c third received data extraction unit, 103 variable dispersion compensation unit, 103a First variable dispersion compensation unit, 103b Second variable dispersion compensation unit, 103c Third variable dispersion compensation 104 dispersion compensation amount setting unit 104a first dispersion compensation amount setting unit 104b second dispersion compensation amount setting unit 104c third dispersion compensation amount setting unit 105 dispersion compensation amount monitoring unit 106 compensation data notification unit 107a First dispersion compensation amount notification unit, 107b Second dispersion compensation amount notification unit, 107c Third dispersion compensation amount notification unit, 201 Transmission data generation unit, 202 Variable dispersion compensation unit, 203 Dispersion compensation amount monitoring unit, 300, 301, 302 Optical transmission system.

Claims (11)

A variable dispersion compensator that compensates for the delay difference of the optical signal generated in the transmission path;
A dispersion compensation amount setting unit for setting a compensation amount for the optical signal of the variable dispersion compensation unit according to an error correction value of the data signal obtained from the optical signal;
A dispersion compensation amount monitoring unit that detects a failure of the optical transmission device main body or an abnormality of the transmission path using the compensation amount, and notifies the occurrence of the failure or the abnormality to the outside,
An optical transmission device comprising: A variable dispersion compensator that compensates for a delay difference of the optical signal generated in the transmission path, and a dispersion that sets a compensation amount for the optical signal of the variable dispersion compensator according to an error correction value of the data signal obtained from the optical signal A compensation amount setting unit; and a dispersion compensation amount monitoring unit that detects a failure of the optical transmission apparatus main body or an abnormality of the transmission path by using the compensation amount and notifies the occurrence of the failure or the abnormality to the outside. An optical transmission device;
A supervisory control device for displaying the notification;
An optical transmission system comprising:   3. The optical transmission system according to claim 2, wherein the variable dispersion compensation unit, the dispersion compensation amount setting unit, and the dispersion compensation amount monitoring unit are provided in the optical transmission device on the reception side.   3. The optical transmission system according to claim 2, wherein the variable dispersion compensation unit, the dispersion compensation amount setting unit, and the dispersion compensation amount monitoring unit are provided in the optical transmission apparatus on the transmission side. A standby optical transmission device comprising the variable dispersion compensation unit, the dispersion compensation amount setting unit, and the dispersion compensation amount monitoring unit;
The monitoring control device is configured to perform a switching process for switching the optical transmission device to the backup optical transmission device in response to the notification. 5. An optical transmission system according to claim 1.   The optical transmission according to any one of claims 2 to 5, wherein the supervisory control device is configured to execute a recovery process of the optical transmission device in response to the notification. system.   7. The optical transmission system according to claim 6, wherein the supervisory control device is configured to reset or reset the optical transmission device in response to the notification.   The optical transmission system according to claim 6, wherein the monitoring control device is configured to execute the restoration process at a preset time. A variable dispersion compensator that compensates for a delay difference of the optical signal generated in the transmission path, and a dispersion that sets a compensation amount for the optical signal of the variable dispersion compensator according to an error correction value of the data signal obtained from the optical signal An optical transmission device including a plurality of interface boards provided with a compensation amount setting unit and a dispersion compensation amount notification unit for notifying the compensation amount to the outside;
A monitoring control device that detects a failure of each interface board using the compensation amount notified from each dispersion compensation amount notification unit;
An optical transmission system comprising:   The supervisory control device is configured to detect a failure of the optical transmission device or an abnormality of the transmission line using the compensation amount notified from each of the dispersion compensation amount notification units. The optical transmission system according to claim 9. A variable dispersion compensation step for compensating for the delay difference of the optical signal generated in the transmission path with a compensation amount;
A dispersion compensation amount setting step for setting the compensation amount to a correction compensation amount according to an error correction value of a data signal obtained from the optical signal compensated with the compensation amount;
Based on the correction compensation amount, a dispersion compensation amount monitoring step of detecting a failure of the optical transmission apparatus main body or an abnormality of the transmission path and notifying the occurrence of the failure or the abnormality to the outside,
An optical transmission method comprising:

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