Maintenance inspection method, maintenance inspection device and use method

Abstract

To replace an optical amplifier in more suitable timing while taking deterioration of the optical amplifier into consideration.SOLUTION: A maintenance inspection method is a maintenance inspection method for optical amplifiers which comprise LDs, and includes the steps of: acquiring a plurality of pieces of time-series data each representing time variations in measured value of drive currents of LDs of a plurality of optical amplifiers; clustering the plurality of acquired pieces of time-series data to classify the plurality of optical amplifiers into a plurality of clusters; and determining replacement timing for optical amplifiers belonging to at least one of the plurality of clusters into which the plurality of optical amplifiers are classified.SELECTED DRAWING: Figure 4

Description

[Technical field]

[0001] The present disclosure relates to a maintenance inspection method, a maintenance inspection device, and a method of use. [Background technology]

[0002] Conventionally, in optical communication systems, a technology is used to amplify optical signals using an optical amplifier equipped with an LD (Laser Diode) for excitation. For example, Non-Patent Document 1 (Toshio Kimura and six others, "250mW 1480 nm LD Module for Exciting Optical Amplifiers", Furukawa Electric Review, Furukawa Electric Co., Ltd., January 2000, No. 105, pp. 19-23) describes that, taking into consideration the degradation of LD in an optical amplifier, the EOL (End Of Life) drive current is defined as 1.2 times the LD drive current value at the beginning of the product. [Prior art documents] [Non-patent literature]

[0003] [Non-Patent Document 1] Toshio Kimura and six others, "250mW 1480 nm LD module for optical amplifier excitation", Furukawa Electric Review, Furukawa Electric Co., Ltd., January 2000, No. 105, pp. 19-23 Summary of the Invention [Problem to be solved by the invention]

[0004] There is a need for a technique that goes beyond the technique described in Non-Patent Document 1 and enables replacement of an optical amplifier at a more appropriate time while taking into account the deterioration of the optical amplifier.

[0005] The present disclosure has been made to solve the above-mentioned problems, and its purpose is to provide a maintenance and inspection method, a maintenance and inspection device, and a method of use that enable replacing an optical amplifier at a more appropriate time taking into account deterioration of the optical amplifier. [Means for solving the problem]

[0006] The maintenance and inspection method disclosed herein is a maintenance and inspection method for an optical amplifier equipped with an LD, and includes the steps of acquiring a plurality of time series data each indicating a time change of a measured value of a drive current of the LD in a plurality of the optical amplifiers, classifying the plurality of optical amplifiers into a plurality of clusters by clustering the acquired plurality of time series data, and determining a replacement timing of the optical amplifier belonging to at least one of the plurality of clusters into which the plurality of optical amplifiers are classified.

[0007] One aspect of the present disclosure may be realized not only as a maintenance inspection method having such characteristic processing steps, but also as a maintenance inspection device having a processing unit that executes such characteristic processing, or as a program for causing a computer to execute the steps of such characteristic processing. Furthermore, one aspect of the present disclosure may be realized as a semiconductor integrated circuit that realizes part or all of the maintenance inspection device, or as a maintenance inspection system including the maintenance inspection device. Effect of the Invention

[0008] According to the present disclosure, it is possible to replace an optical amplifier at a more appropriate timing in consideration of deterioration of the optical amplifier. [Brief description of the drawings]

[0009] [Figure 1] FIG. 1 is a diagram showing a configuration of an optical amplifier that is a target for maintenance and inspection by a maintenance and inspection device according to an embodiment of the present disclosure. [Diagram 2] FIG. 2 is a diagram illustrating a configuration of a maintenance and inspection device according to an embodiment of the present disclosure. [Diagram 3] FIG. 3 is a diagram illustrating an example of clustering by a processing unit in the maintenance and inspection device according to the embodiment of the present disclosure. [Figure 4] FIG. 4 is a diagram illustrating an example of a sequence of a maintenance and inspection process in the maintenance and inspection system according to the embodiment of the present disclosure. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0010] First, the contents of the embodiments of the present disclosure will be listed and described.

[0011] (1) A maintenance and inspection method according to an embodiment of the present disclosure is a maintenance and inspection method for an optical amplifier equipped with an LD, comprising the steps of acquiring a plurality of time series data each indicating a change over time in a measured value of a drive current of the LD in a plurality of the optical amplifiers, classifying the plurality of optical amplifiers into a plurality of clusters by clustering the acquired plurality of time series data, and determining a replacement timing for the optical amplifier belonging to at least one of the plurality of clusters into which the plurality of optical amplifiers are classified.

[0012] In this way, by clustering the time-series data of the LD drive current to classify a plurality of optical amplifiers into a plurality of clusters and determining the replacement timing of the optical amplifiers belonging to the cluster, the replacement timing of the optical amplifiers can be determined for each cluster based on the increasing tendency of the LD drive current, so that the appropriate replacement timing can be determined for each optical amplifier with a similar deterioration state. Therefore, the optical amplifiers can be replaced at a more appropriate timing taking into account the deterioration of the optical amplifiers.

[0013] (2) In the above (1), in the step of determining the replacement timing, an arrival timing, which is the timing at which the drive current reaches a predetermined upper limit value, may be estimated, and the estimated arrival timing may be determined as the replacement timing.

[0014] By using this method, it is possible to systematically replace optical amplifiers using replacement timing determined based on the upper limit of the drive current.

[0015] (3) In the above (2), in the step of determining the replacement timing, the arrival timing may be estimated for each cluster using the upper limit value that differs for each cluster.

[0016] With this method, for example, it is possible to determine a more appropriate replacement timing by using a different upper limit value according to the progress rate of the increase in the LD drive current.

[0017] (4) In the above (2) or (3), the maintenance and inspection method may further include a step of identifying a manufacturing lot of the optical amplifier for which the replacement timing has been determined, and a step of determining the estimated arrival timing as the replacement timing of the optical amplifier manufactured in the identified manufacturing lot and not belonging to the cluster.

[0018] The increasing trend of LD drive current may be similar for each production lot of the main components of an optical amplifier, and this method makes it possible to determine the replacement timing of an optical amplifier whose drive current is monitored, as well as the replacement timing of optical amplifiers manufactured in the same production lot as the optical amplifier whose drive current is not monitored.

[0019] (5) In any of (1) to (4) above, in the step of acquiring the plurality of time series data, the time series data may be acquired that indicates a change over time in the measurement value corrected using a temperature correction coefficient preset for each optical amplifier and a measurement result of the temperature of the optical amplifier.

[0020] With this method, it is possible to determine a more appropriate replacement timing based on a more accurate increase in the drive current associated with LD degradation, taking into account the effect of temperature on the drive current of the LD.

[0021] (6) In any of (1) to (5) above, the maintenance and inspection method may further include a step of strengthening cooling of the optical amplifier when the time until the replacement timing of the optical amplifier determined in the step of determining the replacement timing is less than a predetermined value.

[0022] By using this method, it is possible to reduce the possibility that an optical amplifier, which has a short grace period until the end of its life, will break down before it can be replaced.

[0023] (7) A maintenance and inspection device according to an embodiment of the present disclosure is a maintenance and inspection device used for maintenance and inspection of optical amplifiers equipped with LDs, and includes an acquisition unit that acquires multiple time series data each indicating a time change of a measured value of a drive current of the LD in the multiple optical amplifiers, a classification unit that classifies the multiple optical amplifiers into multiple clusters by clustering the multiple time series data acquired by the acquisition unit, and a determination unit that determines the replacement timing of the optical amplifiers belonging to at least one of the multiple clusters into which the multiple optical amplifiers have been classified by the classification unit.

[0024] In this way, by clustering the time-series data of the LD drive current to classify multiple optical amplifiers into multiple clusters and determining the replacement timing of the optical amplifiers belonging to a cluster, the replacement timing of the optical amplifiers can be determined for each cluster based on the increasing trend of the LD drive current, so that the appropriate replacement timing can be determined for each optical amplifier with a similar deterioration state. Therefore, the optical amplifiers can be replaced at a more appropriate timing taking into account the deterioration of the optical amplifiers.

[0025] (8) A method of use according to an embodiment of the present disclosure is a method of using an optical amplifier equipped with an LD, comprising the steps of installing a plurality of the optical amplifiers, operating the plurality of optical amplifiers, acquiring a plurality of time series data each indicating a change over time in a measured value of a drive current of the LD in the plurality of optical amplifiers while they are being operated, acquiring a replacement timing for the optical amplifier determined based on a result of clustering the plurality of acquired time series data, and replacing the optical amplifier at the acquired replacement timing.

[0026] In this way, by using a method for replacing an optical amplifier at a replacement timing determined based on the result of clustering the time-series data of the LD drive current, it is possible to determine an appropriate replacement timing based on the deterioration state of the optical amplifier, which is determined for each cluster based on the increasing tendency of the LD drive current. Therefore, it is possible to replace the optical amplifier at a more appropriate timing taking into account the deterioration of the optical amplifier.

[0027] Hereinafter, embodiments of the present disclosure will be described with reference to the drawings. In the drawings, the same or corresponding parts are denoted by the same reference numerals, and the description thereof will not be repeated. In addition, at least some of the embodiments described below may be arbitrarily combined.

[0028] [Configuration and basic operation] (Optical amplifier) FIG. 1 is a diagram showing a configuration of an optical amplifier to be inspected by a maintenance and inspection device according to an embodiment of the present disclosure. Referring to FIG. 1, an optical amplifier 101 includes an input connector 11, optical couplers 12A, 12B, and 12C, isolators 13A and 13B, an Er-doped fiber 14, an LD 15, detection PDs (Photo Diodes) 16A and 16B, a control unit 17, a measurement unit 18, and an output connector 19. The optical amplifier 101 may further include a Peltier element. The input connector 11, the optical couplers 12A, 12B, and 12C, the isolators 13A and 13B, the Er-doped fiber 14, the LD 15, and the detection PDs 16A and 16B are connected via optical fibers. A part or all of the control unit 17 and the measurement unit 18 are realized, for example, by a processing circuit including one or more processors.

[0029] The multiple optical amplifiers 101 are used in an optical broadcasting device 111 installed in a broadcasting company's premises, and are constantly operated in the optical broadcasting device 111. The optical amplifiers 101 amplify optical signals for broadcasting. Note that the multiple optical amplifiers 101 may be used in an optical communication device installed in, for example, a communications company's premises. In this case, the optical amplifiers 101 amplify optical signals for communication.

[0030] More specifically, the optical coupler 12A receives an optical signal from an optical signal generating device (not shown) outside the optical amplifier 101 via the input connector 11, and branches the received optical signal at a predetermined branching ratio. The optical coupler 12A outputs a part of the branched optical signal to the isolator 13A, and outputs the other part of the branched optical signal to the detection PD 16A.

[0031] The detection PD 16A outputs to the control unit 17 an electrical signal whose level corresponds to the level of the optical signal received from the optical coupler 12A.

[0032] The LD 15 is a light source for excitation, and outputs excitation light at a level corresponding to the drive current supplied from the control unit 17 to the optical coupler 12B.

[0033] The optical coupler 12B multiplexes the optical signal received from the optical coupler 12A via the isolator 13A with the pumping light received from the LD 15, and outputs the multiplexed signal to the Er-doped fiber .

[0034] The Er-doped fiber 14 amplifies the optical signal received from the optical coupler 12B and outputs it to the isolator 13B.

[0035] The optical coupler 12C branches the amplified optical signal received from the Er-doped fiber 14 via the isolator 13B at a predetermined branching ratio. The optical coupler 12C transmits a part of the branched optical signal to the outside of the optical amplifier 101 via the output connector 19, and outputs the other part of the branched optical signal to the detection PD 16B.

[0036] The detection PD 16B outputs to the control unit 17 an electrical signal whose level corresponds to the level of the optical signal received from the optical coupler 12C.

[0037] The control unit 17 outputs a drive current to the LD 15 during a period in which the level of the electrical signal received from the detection PD 16A is equal to or higher than a predetermined value. The control unit 17 feedback-controls the drive current of the LD 15 based on the electrical signal received from the detection PD 16B. More specifically, the control unit 17 detects the level of the amplified optical signal in the Er-doped fiber 14 based on the electrical signal received from the detection PD 16B, and adjusts the level of the drive current output to the LD 15 so that the level of the amplified optical signal approaches a predetermined value.

[0038] The measurement unit 18 measures the drive current of the LD 15. More specifically, the measurement unit 18 measures the drive current output from the control unit 17 to the LD 15, for example, at a measurement timing according to a predetermined measurement cycle. The measurement unit 18 also measures the temperature of the LD 15, for example, at a measurement timing according to a predetermined measurement cycle. The measurement unit 18 generates time series data D1 indicating a time change in the measured value of the drive current and time series data D2 indicating a time change in the measured value of the temperature. More specifically, the measurement unit 18 generates time series data D1 indicating a correspondence relationship between the measurement timing and the measured value of the drive current, and time series data D2 indicating a correspondence relationship between the measurement timing and the measured value of the temperature.

[0039] A collecting device 121 installed in a broadcasting company's station collects time series data D1 and D2 from the measuring units 18 in the multiple optical amplifiers 101 to be monitored. The collecting device 121 stores the collected time series data D1 and D2 in a memory, for example, including the ID of the corresponding optical amplifier 101.

[0040] [assignment] In the optical amplifier 101, the drive current of the LD 15 increases as the LD 15 deteriorates. The life of the LD 15 is shorter than that of other parts in the optical amplifier 101, and when the drive current of the LD 15 reaches the rated current, the optical amplifier 101 may break down. Generally, in the optical broadcasting device 111, replacement is performed on a regular or irregular basis for each optical amplifier 101. It is preferable to preventively or systematically replace the optical amplifier 101, which is the replacement maintenance unit, before the drive current of the LD 15 reaches the rated current, rather than replacing the optical amplifier 101 after it breaks down.

[0041] However, due to variations in the circular symmetry of the optical fiber used in the optical amplifier 101 and differences in the manufacturing lots of the main components such as the LD 15 in the optical amplifier 101, the drive current of the LD 15 may vary from one optical amplifier 101 to another. For example, the combination of main components from a specific manufacturing lot may significantly increase the drive current of the LD 15. Therefore, the appropriate replacement timing for each optical amplifier 101 or each manufacturing lot of the main components may differ.

[0042] For this reason, there is a need for a technique that allows replacement of the optical amplifier 101 at a more appropriate timing in consideration of deterioration of the optical amplifier 101. Therefore, the maintenance and inspection device 201 according to the embodiment of the present disclosure solves the above problem by having the following configuration.

[0043] (Maintenance and inspection equipment) FIG. 2 is a diagram showing a configuration of a maintenance inspection device according to an embodiment of the present disclosure. With reference to FIG. 2, the maintenance inspection device 201 includes an acquisition unit 21, a processing unit 22, and a storage unit 23. The processing unit 22 is an example of a classification unit and an example of a determination unit. The acquisition unit 21 and the processing unit 22 are partly or entirely realized by, for example, a processing circuit including one or more processors. The storage unit 23 is, for example, a non-volatile memory included in the processing circuit. The maintenance inspection device 201 is used for the maintenance inspection of the optical amplifier 101, and determines the replacement timing of the optical amplifier 101. The maintenance inspection device 201 may determine the replacement timing of another optical amplifier having a different configuration from the optical amplifier 101 shown in FIG. 1.

[0044] The acquiring unit 21 acquires a plurality of time series data D1 indicating the time change of the measured value of the drive current of the LD 15 in each of the optical amplifiers 101. More specifically, the acquiring unit 21 receives the time series data D1, D2 of each optical amplifier 101 to be monitored from the above-mentioned collecting device 121. The acquiring unit 21 stores the received plurality of time series data D1, D2 in the storage unit 23.

[0045] For example, the acquiring unit 21 corrects the time series data D1 using a temperature correction coefficient preset for each optical amplifier 101 and the measurement result of the temperature of the optical amplifier 101.

[0046] More specifically, the drive current of the LD 15 in the optical amplifier 101 increases or decreases depending on the temperature inside the optical amplifier 101. The storage unit 23 stores, for each ID of the optical amplifier 101, correction coefficient information indicating the correspondence between the temperature of the LD 15 and a temperature correction coefficient for correcting the measurement value of the drive current of the LD 15 in the optical amplifier 101.

[0047] The acquiring unit 21 acquires, for each optical amplifier 101, a temperature correction coefficient corresponding to the temperature of the LD 15 indicated by the time series data D2 of the optical amplifier 101 from the correction coefficient information in the storage unit 23. Then, the acquiring unit 21 corrects the time series data D1 of the optical amplifier 101 by multiplying the time series data D1 of the optical amplifier 101 by the acquired temperature correction coefficient. The acquiring unit 21 stores the corrected time series data D1 in the storage unit 23.

[0048] The processing unit 22 classifies the optical amplifiers 101 into a plurality of clusters CL by clustering the plurality of time series data D1 acquired by the acquisition unit 21. More specifically, when the processing unit 22 completes correction of the plurality of time series data D1 corresponding to the plurality of optical amplifiers 101 to be monitored, the processing unit 22 acquires the plurality of corrected time series data D1 from the storage unit 23. The processing unit 22 clusters the acquired plurality of time series data D1 according to a predetermined statistical processing method.

[0049] More specifically, for example, the storage unit 23 stores operation information indicating a correspondence relationship between the ID of the optical amplifier 101 and the drive start timing of the optical amplifier 101. The operation information is provided by a broadcasting company. For example, the drive start timing may be the same as the time when the optical amplifier 101 is installed, or may be a time later than the time when the optical amplifier 101 is installed.

[0050] The processing unit 22 performs a conversion process to convert the measurement timing indicated by the time series data D1 into an accumulated operation time, which is the elapsed time from the drive start timing of the optical amplifier 101, based on the operation information in the storage unit 23. Then, the processing unit 22 clusters the multiple time series data D1 after the conversion process.

[0051] After the optical amplifier 101 starts operating, it may be temporarily stopped for maintenance or the like. Even in this case, the stop time is shorter than the accumulated operating time, so the time elapsed from the timing of starting operation can be regarded as the accumulated operating time. In other words, the accumulated operating time can be approximated by the time elapsed from the timing of starting operation. Also, a second-hand optical amplifier 101 may be installed in a broadcasting company's station building. In this case, the processing unit 22 performs a process of adding the accumulated operating time of the optical amplifier 101 before installation to the accumulated operating time calculated based on the operating information and the measurement timing.

[0052] The acquiring unit 21 may be configured to acquire time series data D1 indicating the correspondence relationship between the accumulated operating time and the measured value of the drive current. In this case, the processing unit 22 performs clustering on the multiple time series data D1 without performing a conversion process.

[0053] 3 is a diagram illustrating an example of clustering by a processing unit in a maintenance and inspection device according to an embodiment of the present disclosure, in which the horizontal axis represents cumulative operation time and the vertical axis represents the drive current [A] of the LD 15.

[0054] 3, for example, the processing unit 22 clusters a plurality of time series data D1 to generate a cluster CLA which is a cluster CL to which the time series data D1a, D1b, and D1c which are the time series data D1 belong, and a cluster CLB which is a cluster CL to which the time series data D1d, D1e, D1f, D1g, and D1h which are the time series data D1 belong, by clustering the plurality of time series data D1. Then, the processing unit 22 classifies three optical amplifiers 101 corresponding to the time series data D1a, D1b, and D1c, respectively, into the cluster CLA, and classifies five optical amplifiers 101 corresponding to the time series data D1d, D1e, D1f, D1g, and D1h, respectively, into the cluster CLB.

[0055] The processing unit 22 determines the replacement timing of the optical amplifier 101 belonging to at least one of the clusters CL into which the optical amplifiers 101 are classified. For example, the processing unit 22 estimates an arrival timing Ta at which the drive current of the LD 15 in the optical amplifier 101 reaches a predetermined upper limit value Th, and determines the estimated arrival timing Ta as the replacement timing of the optical amplifier 101.

[0056] More specifically, the processing unit 22 creates an extrapolated line ELA which is an extrapolated line EL of the time series data D1a, D1b, and D1c, and an extrapolated line ELB which is an extrapolated line EL of the time series data D1d, D1e, D1f, D1g, and D1h. The processing unit 22 determines an arrival timing TaA, which is a time corresponding to the upper limit value Th on the extrapolated line ELA, as the replacement timing of the optical amplifier 101 belonging to the cluster CLA. The processing unit 22 also determines an arrival timing TaB, which is a time corresponding to the upper limit value Th on the extrapolated line ELB, as the replacement timing of the optical amplifier 101 belonging to the cluster CLB. The processing unit 22 notifies the broadcaster of the determined replacement timing.

[0057] Here, the main parts of the optical amplifier 101 other than the LD 15 may have a lifespan equal to or shorter than that of the LD 15 due to manufacturing defects, etc. In this way, even if the main parts other than the LD 15 are defective, the drive current of the LD 15 increases as a result, which affects the increasing trend of the drive current, so that the appropriate replacement timing for the optical amplifier 101 can be determined based on the time-series data D1 indicating the time change in the drive current of the LD 15.

[0058] For example, when the time until the determined replacement timing of the optical amplifier 101 is less than a predetermined value, the processing unit 22 performs processing to strengthen the cooling of the optical amplifier 101. More specifically, when the time until the replacement timing of the optical amplifier 101 belonging to the cluster CLA is less than a predetermined value, the processing unit 22 remotely controls a cooling fan in the broadcaster's station building to operate the cooling fan for cooling the optical amplifier 101 belonging to the cluster CLA or to increase the rotation speed of the cooling fan. Instead of remotely controlling the cooling fan, the processing unit 22 may notify the broadcaster of a warning to the effect that cooling of the optical amplifier 101 belonging to the cluster CLA should be strengthened.

[0059] The processing unit 22 may be configured to estimate the arrival timing Ta for each cluster CL using a different upper limit value Th for each cluster CL. More specifically, the processing unit 22 sets, for example, an upper limit value ThA that is an upper limit value Th according to the gradient of the extrapolation line ELA, and an upper limit value ThB that is an upper limit value Th according to the gradient of the extrapolation line ELB. Here, the upper limit value ThA is assumed to be smaller than the upper limit value ThB. Then, the processing unit 22 determines the arrival timing TaA, which is a time corresponding to the upper limit value ThA on the extrapolation line ELA, as the replacement timing of the optical amplifier 101 belonging to the cluster CLA. Also, the processing unit 22 determines the arrival timing TaB, which is a time corresponding to the upper limit value ThB on the extrapolation line ELA, as the replacement timing of the optical amplifier 101 belonging to the cluster CLB.

[0060] The processing unit 22 may be configured not to determine the replacement timing of the optical amplifiers 101 that belong to some of the clusters CL among the multiple clusters CL. More specifically, when the gradient of the extrapolation line EL is less than a predetermined value, the processing unit 22 determines that it is not necessary at this time to determine the replacement timing of the optical amplifiers 101 that belong to the cluster CL corresponding to the extrapolation line EL.

[0061] For example, the processing unit 22 identifies the manufacturing lot of the optical amplifier 101 for which the replacement timing has been determined. As an example, the processing unit 22 identifies the manufacturing lot number assigned to the optical amplifier 101, which indicates the manufacturing lot of the optical amplifier 101 for which the replacement timing has been determined.

[0062] More specifically, the storage unit 23 stores lot information indicating the correspondence between the ID of the optical amplifier 101 and the manufacturing lot number of the main components of the optical amplifier 101.

[0063] The processing unit 22 refers to the lot information in the memory unit 23 and identifies the manufacturing lot numbers of the main parts of the optical amplifier 101 belonging to the cluster CLA for which the arrival time TaA has been determined as the replacement timing, and the manufacturing lot numbers of the main parts of the optical amplifier 101 belonging to the cluster CLB for which the arrival time TaB has been determined as the replacement timing.

[0064] Then, the processing unit 22 determines the arrival time Ta as the replacement timing of the optical amplifier 101 that was manufactured in the identified manufacturing lot and does not belong to the cluster CL.

[0065] More specifically, the processing unit 22 determines the arrival timing TaA as the replacement timing of an optical amplifier 101 other than the optical amplifier 101 to be monitored by the collecting device 121 described above and having the same manufacturing lot number of the main parts as the optical amplifier 101 belonging to the cluster CLA. Also, the processing unit 22 determines the arrival timing TaB as the replacement timing of an optical amplifier 101 other than the optical amplifier 101 to be monitored by the collecting device 121 described above and having the same manufacturing lot number of the main parts as the optical amplifier 101 belonging to the cluster CLB. The processing unit 22 notifies the broadcasting company of the determined replacement timing. Note that the processing unit 22 may specify a code indicating the manufacturing lot of the optical amplifier 101 in question instead of the manufacturing lot number assigned to the optical amplifier 101.

[0066] [Operation flow] FIG. 4 is a diagram illustrating an example of a sequence of a maintenance and inspection process in the maintenance and inspection system according to the embodiment of the present disclosure.

[0067] 4, first, the broadcaster installs a plurality of optical amplifiers 101. More specifically, the broadcaster installs an optical broadcasting device 111 including a plurality of optical amplifiers 101 (step S11).

[0068] Next, the broadcaster drives the optical amplifiers 101 in the optical broadcasting device 111 (step S12).

[0069] Next, the collecting device 121 installed in the broadcasting company's station acquires a plurality of time-series data D1 each indicating a time change in the measured value of the driving current of the LD 15 in each of the optical amplifiers 101 that are currently being driven. More specifically, the collecting device 121 collects the time-series data D1 and D2 from the measuring units 18 in each of the optical amplifiers 101 to be monitored (step S13).

[0070] Next, the collection device 121 transmits the collected time series data D1 and D2 to the maintenance and inspection device 201 (step S14).

[0071] Next, the maintenance and inspection device 201 corrects the time series data D1 using a temperature correction coefficient preset for each optical amplifier 101 and the measurement result of the temperature of the optical amplifier 101. More specifically, the maintenance and inspection device 201 corrects the time series data D1 by multiplying the time series data D1 received from the collection device 121 by the temperature correction coefficient (step S15).

[0072] Next, the maintenance and inspection device 201 classifies the optical amplifiers 101 into a plurality of clusters CL by clustering the plurality of time-series data D1 (step S16).

[0073] Next, the maintenance and inspection device 201 determines the replacement timing of the optical amplifier 101 that belongs to at least one of the clusters CL. More specifically, the maintenance and inspection device 201 estimates the arrival timing Ta, which is the timing at which the drive current of the LD 15 in the optical amplifier 101 reaches the upper limit value Th, and determines the estimated arrival timing Ta as the replacement timing of the optical amplifier 101. Also, for example, the maintenance and inspection device 201 determines the arrival timing Ta as the replacement timing of another optical amplifier 101 that is assigned the identified manufacturing lot number and does not belong to the cluster CL (step S17).

[0074] Next, the maintenance and inspection device 201 notifies the broadcaster of the determined replacement timing (step S18).

[0075] Next, if the time until the optical amplifier 101 needs to be replaced is less than a predetermined value, the maintenance and inspection device 201 performs processing to strengthen cooling of the optical amplifier 101 by remotely controlling the cooling fan at the broadcasting company (step S19).

[0076] Next, the broadcasting company receives notification of the replacement timing determined based on the result of clustering the multiple time series data D1, waits for the replacement timing, and replaces the optical amplifier 101 at the replacement timing (step S20).

[0077] The broadcasting company may install additional optical amplifiers 101 after installing a plurality of optical amplifiers 101 in step S11.

[0078] When the time that has elapsed since the drive start time of the optical amplifier 101 is short, the maintenance and inspection device 201 may not be able to perform clustering of the time series data D1 with high accuracy and may not be able to classify the optical amplifier 101 into a cluster CL. For example, when the maintenance and inspection device 201 cannot classify the optical amplifier 101 into a cluster CL, it may determine that it is not necessary to determine the timing of replacement of the optical amplifier 101 at the present time. Even in this case, after a certain amount of time has elapsed since the drive start time of the optical amplifier 101, the maintenance and inspection device 201 can classify the optical amplifier 101 into any of the clusters CL or generate a new cluster CL to which the optical amplifier 101 belongs, as deterioration progresses according to the time that has elapsed since the drive start time. Therefore, it is possible to determine the replacement timing before the optical amplifier 101 breaks down.

[0079] Instead of performing the process of step S19, the maintenance and inspection device 201 may notify the broadcaster of a warning to the effect that cooling of the optical amplifier 101 belonging to the cluster CLA should be strengthened. In this case, the broadcaster strengthens cooling of the optical amplifier 101 in accordance with the warning.

[0080] In addition, in the maintenance and inspection device 201 according to the embodiment of the present disclosure, the processing unit 22 is configured to estimate the arrival timing Ta, which is the timing when the drive current of the LD 15 in the optical amplifier 101 reaches a predetermined upper limit value Th, and to determine the estimated arrival timing Ta as the replacement timing of the optical amplifier 101, but this is not limited thereto. The processing unit 22 may be configured to determine that the optical amplifier 101 belonging to the cluster CL corresponding to the extrapolation line EL is abnormal when the gradient of the extrapolation line EL is equal to or greater than a predetermined value, and to determine a predetermined timing, for example, the present day, as the replacement timing without estimating the arrival timing Ta. In this case, for example, the processing unit 22 notifies the broadcasting company of the determined replacement timing together with a predetermined warning.

[0081] Also, for example, the processing unit 22 may be configured to prompt replacement of the optical amplifier 101 belonging to at least one of the multiple clusters CL when the average value of the slope of the time series data D1 belonging to that cluster CL is equal to or greater than a predetermined value.

[0082] Furthermore, in the maintenance and inspection device 201 according to the embodiment of the present disclosure, the processing unit 22 is configured to determine the replacement timing of optical amplifiers 101 other than the optical amplifiers 101 to be monitored by the collecting device 121, but this is not limiting. The processing unit 22 may be configured to determine the replacement timing of optical amplifiers 101 to be monitored by the collecting device 121, but not to determine the replacement timing of optical amplifiers 101 other than the optical amplifiers 101 to be monitored by the collecting device 121. In this case, the processing unit 22 does not need to identify the manufacturing lot number assigned to the optical amplifier 101 for which the replacement timing has been determined.

[0083] In addition, in the maintenance and inspection device 201 according to the embodiment of the present disclosure, the processing unit 22 is configured to perform processing to strengthen cooling of the optical amplifier 101 when the time until the optical amplifier 101 needs to be replaced is less than a predetermined value, but this is not limited to this. The processing unit 22 may be configured not to perform processing to strengthen cooling of the optical amplifier 101.

[0084] In addition, in the maintenance and inspection device 201 according to the embodiment of the present disclosure, the acquiring unit 21 is configured to correct the time series data D1 using a temperature correction coefficient preset for each optical amplifier 101 and the measurement result of the temperature of the optical amplifier 101, but this is not limited to the above. The acquiring unit 21 may be configured not to correct the time series data D1. In this case, the measuring unit 18 in the optical amplifier 101 may be configured not to generate the time series data D2.

[0085] The above-described embodiments should be considered as illustrative and not restrictive in all respects. The scope of the present invention is defined by the claims, not by the above description, and is intended to include all modifications within the meaning and scope of the claims.

[0086] Each process (each function) of the above-mentioned embodiment is realized by a processing circuit (circuitry) including one or more processors. The above-mentioned processing circuit may be composed of an integrated circuit or the like in which one or more memories, various analog circuits, and various digital circuits are combined in addition to the above-mentioned one or more processors. The above-mentioned one or more memories store programs (instructions) that cause the above-mentioned one or more processors to execute each of the above-mentioned processes. The above-mentioned one or more processors may execute each of the above-mentioned processes according to the programs read from the above-mentioned one or more memories, or may execute each of the above-mentioned processes according to a logic circuit designed in advance to execute each of the above-mentioned processes. The above-mentioned processors may be various processors suitable for computer control, such as a CPU (Central Processing Unit), a GPU (Graphics Processing Unit), a DSP (Digital Signal Processor), an FPGA (Field Programmable Gate Array), and an ASIC (Application Specific Integrated Circuit). The above-mentioned physically separated processors may execute each of the above-mentioned processes in cooperation with each other. For example, the processors mounted on each of a plurality of physically separated computers may cooperate with each other via a network such as a LAN (Local Area Network), a WAN (Wide Area Network), the Internet, etc. The program may be installed in the memory from an external server device or the like via the network, or may be distributed in a state stored in a recording medium such as a CD-ROM (Compact Disc Read Only Memory), a DVD-ROM (Digital Versatile Disc Read Only Memory), or a semiconductor memory, and installed in the memory from the recording medium.

[0087] The above description includes the following additional features. [Appendix 1] A method for maintaining and inspecting an optical amplifier equipped with an LD, comprising the steps of: acquiring a plurality of time series data each indicating a time change of a measured value of a drive current of the LD in each of the plurality of optical amplifiers; classifying the optical amplifiers into a plurality of clusters by clustering the plurality of acquired time-series data; determining a replacement timing of the optical amplifier belonging to at least one of the plurality of clusters into which the plurality of optical amplifiers are classified; A maintenance and inspection method in which, in the step of determining the replacement timing, if a slope of an extrapolation line of the time series data of the optical amplifier belonging to the cluster is equal to or greater than a predetermined value, the optical amplifier belonging to the cluster is determined to be abnormal, and the replacement timing of the optical amplifier determined to be abnormal is determined to be a predetermined timing. [Explanation of symbols]

[0088] 11 Input Connector 12A, 12B, 12C Optical Couplers 13A, 13B Isolator 14 Er-doped fiber 15LD 16A, 16B Detection PD 17 Control Unit 18 Measurement section 21 Acquisition Department 22 Processing section 23 Memory section 101 Optical Amplifier 111 Optical broadcasting equipment 121 Collecting Device 201 Maintenance and inspection equipment D1a, D1b, D1c, D1d, D1e, D1f, D1g, D1h Time series data CLA,CLB Cluster ELA,ELB extrapolation line Th Upper limit TaA,TaB arrival timing

Claims

1. A method for maintaining and inspecting an optical amplifier including a laser diode (LD), comprising: acquiring a plurality of time series data indicating time changes of measured values ​​of the driving current of the LD in each of the plurality of optical amplifiers; classifying the optical amplifiers into a plurality of clusters by clustering the plurality of acquired time-series data; determining replacement timing of the optical amplifiers belonging to at least one of the plurality of clusters into which the plurality of optical amplifiers are classified.

2. 2. The maintenance and inspection method according to claim 1, wherein in the step of determining the replacement timing, a timing at which the drive current reaches a predetermined upper limit value is estimated, and the estimated timing is determined as the replacement timing.

3. 3. The maintenance and inspection method according to claim 2, wherein in the step of determining the replacement timing, the arrival timing is estimated for each of the clusters using the upper limit value that differs for each of the clusters.

4. The maintenance and inspection method further comprises: identifying a manufacturing lot of the optical amplifier for which the replacement timing has been determined; 3. The maintenance and inspection method according to claim 2, further comprising the step of determining the estimated arrival timing as the replacement timing of the optical amplifier manufactured in the identified manufacturing lot and not belonging to the cluster.

5. 5. A maintenance and inspection method according to claim 1, wherein in the step of acquiring the plurality of time series data, the time series data indicating the time change of the measurement value corrected using a temperature correction coefficient preset for each optical amplifier and a measurement result of the temperature of the optical amplifier is acquired.

6. The maintenance and inspection method further comprises:

5. A maintenance and inspection method according to claim 1, further comprising a step of strengthening cooling of the optical amplifier when the time until the replacement timing of the optical amplifier determined in the step of determining the replacement timing is less than a predetermined value.

7. A maintenance and inspection device used for maintenance and inspection of an optical amplifier equipped with an LD, an acquisition unit that acquires a plurality of time series data indicating a time change of a measured value of a drive current of the LD in each of the plurality of optical amplifiers; a classification unit that classifies the optical amplifiers into a plurality of clusters by clustering the plurality of time-series data acquired by the acquisition unit; a determination unit that determines a replacement timing of the optical amplifier that belongs to at least one of the plurality of clusters into which the plurality of optical amplifiers are classified by the classification unit.

8. A method for using an optical amplifier including an LD, comprising the steps of: providing a plurality of said optical amplifiers; driving the plurality of optical amplifiers; acquiring a plurality of time series data each indicating a change over time in a measured value of a drive current of the LD in each of the optical amplifiers being driven; acquiring a replacement timing for the optical amplifier, the replacement timing being determined based on a result of clustering the acquired plurality of time-series data; and replacing the optical amplifier at the acquired replacement timing.

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