Optical monitoring device, optical monitoring system, and optical monitoring method

Abstract

In a submarine optical cable system using an open cable mode, the switching state of a branching device cannot be monitored during the initial introduction. A light monitoring device according to the present invention, therefore, comprises: a light spectrum generating means that generates the light spectrum information of propagating light that propagates via a light path switching device for switching signal light paths; an identified-light information generating means that generates, from the light spectrum information, identified-light information related to the spectrum form of identified light included in the propagating light; and a switching state determining means that determines the switching state of the light path switching device from the identified-light information.

Description

[Technical Field]

[0001] The present invention relates to an optical monitoring device, an optical monitoring system, and an optical monitoring method, and more particularly to an optical monitoring device, an optical monitoring system, and an optical monitoring method used in an optical submarine cable system. [Background technology]

[0002] Optical submarine cable systems that connect continents with optical fibers play an important role as infrastructure supporting international communication networks. An optical submarine cable system is composed of submarine cables that accommodate optical fibers, optical repeaters equipped with optical amplifiers, branching devices that branch optical signals, and terminal equipment installed at landing stations. An example of such an optical submarine cable system is described in Patent Document 1. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 2018-078452 Summary of the Invention [Problem to be solved by the invention]

[0004] In recent years, optical submarine cable systems have generally adopted a configuration in which branching units (BUs) equipped with optical switches are introduced in the optical transmission path, enabling switching of optical transmission paths. In such optical submarine cable systems, the switching status of the branching units installed on the seabed is monitored using optical transceivers such as transponders installed at landing stations.

[0005] Meanwhile, in optical submarine cable systems, the open cable method, in which transponders with open specifications are procured individually, is becoming more common. In such open cable optical submarine cable systems, only submarine equipment such as optical repeaters and branching devices and submarine cables are installed at the time of initial installation, and optical transmitters and receivers such as transponders are not necessarily installed. In this case, it is difficult to monitor the switching status of branching devices at the time of initial installation of the optical submarine cable system.

[0006] Thus, in an optical submarine cable system using the open cable method, there was a problem in that the switching status of the branching devices could not be monitored at the time of initial installation.

[0007] An object of the present invention is to provide an optical monitoring device, an optical monitoring system, and an optical monitoring method that solve the problem that in an open cable type optical submarine cable system, the switching status of a branching device cannot be monitored at the time of initial installation. [Means for solving the problem]

[0008] The optical monitoring device of the present invention comprises an optical spectrum generating means for generating optical spectrum information of propagating light propagating through an optical path switching device that switches the path of signal light, an identification light information generating means for generating, from the optical spectrum information, identification light information relating to the spectral form of identification light contained in the propagating light, and a switching state determining means for determining the switching state of the optical path switching device from the identification light information.

[0009] The optical monitoring method of the present invention generates optical spectrum information of propagating light that propagates through an optical path switching device that switches the path of signal light, generates identification light information regarding the spectral form of identification light contained in the propagating light from the optical spectrum information, and determines the switching state of the optical path switching device from the identification light information. [Effects of the Invention]

[0010] According to the optical monitoring device, optical monitoring system, and optical monitoring method of the present invention, it is possible to monitor the switching state of branching devices at the time of initial installation even in an optical submarine cable system using an open cable method. [Brief explanation of the drawings]

[0011] [Figure 1] 1 is a block diagram showing a configuration of an optical monitoring device according to a first embodiment of the present invention. [Figure 2] 1 is a block diagram showing an example of the configuration of an optical submarine cable system in which an optical monitoring device according to a first embodiment of the present invention is used. [Figure 3] 2 is a diagram showing an example of an optical spectrum of a propagating light received by the optical monitoring device according to the first embodiment of the present invention. FIG. [Figure 4] FIG. 3 is a block diagram showing another example of the configuration of an optical submarine cable system in which the optical monitoring device according to the first embodiment of the present invention is used. [Figure 5A] FIG. 1 is a diagram showing the spectrum of propagating light received by the optical monitoring device according to the first embodiment of the present invention, in which the optical path switching device is in the first switching pattern and the optical monitoring device is provided in terminal station A. [Figure 5B] FIG. 1 is a diagram showing the spectrum of propagating light received by the optical monitoring device according to the first embodiment of the present invention, in which the optical path switching device is in the first switching pattern and the optical monitoring device is provided in terminal station B. [Figure 5C] FIG. 1 is a diagram showing the spectrum of propagating light received by the optical monitoring device according to the first embodiment of the present invention, in which the optical path switching device is in the first switching pattern and the optical monitoring device is provided in terminal station C. [Figure 5D] 1 is a diagram showing a spectrum of propagation light received by an optical monitoring device according to a first embodiment of the present invention, in which the optical path switching device is in the first switching pattern and the optical monitoring device is provided in a terminal station D. FIG. [Figure 6A]FIG. 1 is a diagram showing the spectrum of propagating light received by the optical monitoring device according to the first embodiment of the present invention, in which the optical path switching device is in the second switching pattern and the optical monitoring device is provided in terminal station A. [Figure 6B] FIG. 10 is a diagram showing the spectrum of propagation light received by the optical monitoring device according to the first embodiment of the present invention, in which the optical path switching device is in the second switching pattern and the optical monitoring device is provided in terminal station B. [Figure 6C] FIG. 10 is a diagram showing the spectrum of propagating light received by the optical monitoring device according to the first embodiment of the present invention, in which the optical path switching device is in the second switching pattern and the optical monitoring device is provided in terminal station C. [Figure 6D] FIG. 10 is a diagram showing the spectrum of propagating light received by the optical monitoring device according to the first embodiment of the present invention, in which the optical path switching device is in the second switching pattern and the optical monitoring device is provided in terminal station D. [Figure 7A] FIG. 10 is a diagram showing the spectrum of propagating light received by the optical monitoring device according to the first embodiment of the present invention, in which the optical path switching device is in the third switching pattern and the optical monitoring device is provided in terminal station A. [Figure 7B] FIG. 10 is a diagram showing the spectrum of propagating light received by the optical monitoring device according to the first embodiment of the present invention, in which the optical path switching device is in the third switching pattern and the optical monitoring device is provided in terminal station B. [Figure 7C] FIG. 10 is a diagram showing the spectrum of propagating light received by the optical monitoring device according to the first embodiment of the present invention, in which the optical path switching device is in the third switching pattern and the optical monitoring device is provided in terminal station C. [Figure 7D] FIG. 10 is a diagram showing the spectrum of propagating light received by the optical monitoring device according to the first embodiment of the present invention, in which the optical path switching device is in the third switching pattern and the optical monitoring device is provided in terminal station D. [Figure 8A] FIG. 10 is a diagram showing the spectrum of propagating light received by the optical monitoring device according to the first embodiment of the present invention, in which the optical path switching device is in the fourth switching pattern and the optical monitoring device is provided in terminal station A. [Figure 8B] FIG. 10 is a diagram showing the spectrum of propagating light received by the optical monitoring device according to the first embodiment of the present invention, in which the optical path switching device is in the fourth switching pattern and the optical monitoring device is provided in terminal station B. [Figure 8C] FIG. 10 is a diagram showing the spectrum of propagating light received by the optical monitoring device according to the first embodiment of the present invention, in which the optical path switching device is in the fourth switching pattern and the optical monitoring device is provided in terminal station C. [Figure 8D] FIG. 10 is a diagram showing the spectrum of propagating light received by the optical monitoring device according to the first embodiment of the present invention, in which the optical path switching device is in the fourth switching pattern and the optical monitoring device is provided in terminal station D. [Figure 9] FIG. 3 is a block diagram showing another configuration of the optical monitoring device according to the first embodiment of the present invention. [Figure 10A] 3 is a diagram schematically showing the shape of a spectral line of amplified spontaneous emission light acquired by the optical monitoring device according to the first embodiment of the present invention. FIG. [Figure 10B] 5A and 5B are diagrams schematically showing other shapes of the spectral line of amplified spontaneous emission light acquired by the optical monitoring device according to the first embodiment of the present invention. [Figure 10C] FIG. 10 is a diagram schematically showing still another shape of the spectral line of amplified spontaneous emission light acquired by the optical monitoring device according to the first embodiment of the present invention. [Figure 11] 3 is a flowchart illustrating an optical monitoring method according to the first embodiment of the present invention. [Figure 12] FIG. 10 is a block diagram showing the configuration of an optical monitoring system according to a second embodiment of the present invention. [Figure 13] FIG. 10 is a block diagram showing the configuration of an optical device included in an optical monitoring system according to a second embodiment of the present invention. [Figure 14] FIG. 10 is a block diagram showing another configuration of the optical monitoring system according to the second embodiment of the present invention. [Figure 15] 10 is a flowchart illustrating an optical monitoring method according to a second embodiment of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0012] Hereinafter, an embodiment of the present invention will be described with reference to the drawings.

[0013] [First embodiment] 1 is a block diagram showing the configuration of an optical monitoring device 100 according to a first embodiment of the present invention. The optical monitoring device 100 includes an optical spectrum generation unit (optical spectrum generation means) 110, an identification light information generation unit (identification light information generation means) 120, and a switching state determination unit (switching state determination means) 130. The optical monitoring device 100 is preferably used in a terminal device that constitutes an optical submarine cable system.

[0014] Figure 2 shows the configuration of an optical submarine cable system 10, as an example of an optical submarine cable system, which has terminal stations A, B, and C each equipped with a terminal device, an optical path switching device 11 as a branching device, and an optical repeater 12. The optical path switching device 11 typically comprises an optical switch or an optical add-drop multiplexer (OADM). The optical repeater 12 typically comprises an erbium doped fiber amplifier (EDFA). The optical path switching device 11 and the terminal station devices equipped in each of the terminal stations A, B, and C are connected by, for example, a fiber pair. Here, the fiber pair (FP) consists of an optical fiber for an upstream line and an optical fiber for a downstream line.

[0015] In the optical monitoring device 100 shown in Fig. 1, the optical spectrum generation unit 110 generates optical spectrum information of propagating light propagating via the optical path switching device 11, which switches the path of signal light. The identification light information generation unit 120 generates identification light information relating to the spectral form of the identification light contained in the propagating light from the optical spectrum information. Then, the switching state determination unit 130 determines the switching state of the optical path switching device 11 from the identification light information.

[0016] As described above, the optical monitoring device 100 according to this embodiment is configured to determine the switching state of the optical route switching device 11 from identification light information relating to the spectrum form of identification light contained in the propagating light. Therefore, there is no need to introduce an optical transmitter / receiver such as a transponder to determine the switching state of the optical route switching device 11. In other words, the optical monitoring device 100 according to this embodiment can monitor the switching state of a branching device at the time of initial installation even in an optical submarine cable system using an open cable method.

[0017] An optical interface device (OCI) provided in a terminal device of an open cable optical submarine cable system can be used as the optical monitoring device 100. In this case, an optical channel monitor (OCM) provided in the optical interface device (OCI) can be used as the optical spectrum generation unit 110. However, the present invention is not limited to this, and an optical spectrum analyzer can also be used as the optical spectrum generation unit 110.

[0018] The above-mentioned propagation light is amplified spontaneous emission (ASE) light added by an optical device upstream of the optical path switching device 11. Here, the optical device may be provided in any of terminal stations A, B, and C. The above-mentioned identification light is amplified spontaneous emission (ASE) light having a spectrum form that differs for each optical device.

[0019] Figure 3 shows an example of the optical spectrum of propagating light. Propagating light S10 includes adjustment light S11 in the main signal band to maintain a constant output optical intensity of the optical device. This adjustment light S21 is dummy light that is inserted in place of the main optical signal. Then, identification light S12 is included in an unassigned band excluding the main signal band. By using this arrangement, even after an optical transceiver such as a transponder is connected to the optical submarine cable system and the main signal light is introduced into the main signal band, the identification light S12 can continue to be used. However, the arrangement is not limited to this, and the identification light S12 may be included in the main signal band.

[0020] The spectral form of the identification light S12 described above is at least one of the number of spectral lines of the amplified spontaneous emission light constituting the identification light S12, the band in which the identification light S12 is located, and the shape of the spectral lines. In the example shown in Figure 3, the number of spectral lines is two, the band in which the identification light S12 is located is on the high-frequency side of the main signal band, and the shape of the spectral lines is rectangular. The amount of information in the identification light information can be increased by arranging the identification light S12 also on the low-frequency side of the main signal band or by narrowing the width of the spectral lines to increase the number of spectral lines.

[0021] Next, the operation of the optical monitoring device 100 will be described.

[0022] If the switching state determination unit 130 provided in the optical monitoring device 100 determines that the identification light information indicates an optical device upstream of the optical path switching device 11, it determines that the optical path switching device 11 is in a switching state in which it is connected to this optical device.

[0023] An example will be described in which the optical monitoring device 100 is provided in terminal station A shown in Figure 2. In the optical submarine cable system 10, terminal station A and terminal station B are trunk stations, and terminal station C is a branch station. In this case, the optical path switching device 11, which serves as a branching device, switches between a state in which terminal station A is connected to terminal station B (trunk-through) and a state in which terminal station C is connected to terminal station A, and terminal station C is connected to terminal station B (branch-through).

[0024] When the switching state determination unit 130 determines that the identification optical information indicates a first optical device (optical device provided in terminal station B) among the optical devices to which the optical path switching device 11 is connected in the first switching state (trunk-through), it determines that the optical path switching device 11 is in the first switching state (trunk-through).On the other hand, when the identification optical information determines that a second optical device (optical device provided in terminal station C) among the optical devices to which the optical path switching device 11 is connected in the second switching state (branch-through), it determines that the optical path switching device 11 is in the second switching state (branch-through).

[0025] Next, the operation of the optical monitoring device 100 will be described in more detail.

[0026] Figure 4 shows another example of an optical submarine cable system. The system includes a first optical route switch 21 and a second optical route switch 22 as branching devices, and terminal stations A, B, C, and D. Terminal stations A, B, C, and D are each equipped with an optical monitoring device 100 and the optical devices described above. Figure 4 also shows the spectrum of the propagating light added by the optical devices in terminal stations A, B, C, and D. Figure 4 shows an example in which the spectral widths of the amplified spontaneous emission (ASE) light constituting the modulation light are approximately the same as those of the main signal light. However, modulation light composed of ASE light with a broad spectral line may also be used. Figure 4 also shows the spectrum of the supervisory (SV) signal light between the spectra of the modulation light and the identification light (indicated by the arrow). This supervisory signal light is used to control submarine equipment such as branching devices.

[0027] As shown in Figure 4, the optical equipment installed in each terminal station A, B, C, and D adds an identification light with a different spectrum form for each terminal station. In the example shown in Figure 4, the optical equipment installed in terminal station A adds an identification light consisting of three ASE spectral lines. Similarly, the optical equipment adds an identification light consisting of zero spectral lines at terminal station B, one spectral line at terminal station C, and two spectral lines at terminal station D. Meanwhile, optical monitoring devices 100A, 100B, 100C, and 100D installed in terminal stations A, B, C, and D, respectively, receive the identification light. They then identify the terminal station from which the identification light is added based on the number of ASE spectral lines that make up the identification light, and determine the switching states of the first optical route switching device 21 and the second optical route switching device 22.

[0028] Next, the spectrum of the propagation light received by the optical monitoring device 100 in each terminal station will be described using the example shown in Fig. 4. The terminal station that is the add source of the propagation light received by the optical monitoring device 100 varies depending on the switching state (trunk-through or branch-through) of the first optical path switching device 21 and the second optical path switching device 22. Therefore, the switching state of the first optical path switching device 21 and the second optical path switching device 22 can be determined by identifying the add source terminal station from the spectral form of the identification light included in the propagation light (the number of spectral lines of the ASE light in the above example).

[0029] 5A to 5D show the spectrum of the propagation light received by the optical monitoring device 100 provided in each terminal station. FIGS. 5A to 5D show the case of a first switching pattern in which both the first optical path switching device 21 and the second optical path switching device 22 are in the first switching state (trunk-through). FIG. 5A shows the propagation light spectrum received by the optical monitoring device 100A provided in terminal station A, FIG. 5B shows the propagation light spectrum received by the optical monitoring device 100B provided in terminal station B, FIG. 5C shows the propagation light spectrum received by the optical monitoring device 100C provided in terminal station C, and FIG. 5D shows the propagation light spectrum received by the optical monitoring device 100D provided in terminal station D. The same applies to the following FIGS. 6A to 6D, 7A to 7D, and 8A to 8D.

[0030] As shown in FIG. 5B, the optical monitoring device 100B provided in terminal station B receives an identification light consisting of three spectral lines. From this, the optical monitoring device 100B identifies that the source of this identification light is the optical device provided in terminal station A, and determines that the switching states of the first optical path switching device 21 and the second optical path switching device 22 are the first switching pattern. On the other hand, as shown in FIG. 5C, the optical monitoring device 100C provided in terminal station C does not receive the propagating light, but only receives amplified spontaneous emission (ASE) noise added by the optical repeater. In this case, the optical monitoring device 100C determines that the switching state of the first optical path switching device 21 is the first switching state (trunk-through).

[0031] 6A to 6D show the spectrum of the propagation light received by the optical monitoring device 100 in the second switching pattern in which the first optical path switching device 21 is in the first switching state (trunk-through) and the second optical path switching device 22 is in the second switching state (branch-through). As shown in FIGS. 6A and 6B, the optical monitoring device 100A and the optical monitoring device 100B each receive identification light consisting of two spectral lines. Therefore, the optical monitoring device 100A and the optical monitoring device 100B each identify that the insertion source of this identification light is the optical device provided in the terminal station D. As a result, the optical monitoring device 100A determines that the switching states of the first optical path switching device 21 and the second optical path switching device 22 are in the second switching pattern. On the other hand, the optical monitoring device 100B determines that the switching state of the second optical path switching device 22 is in the second switching state (branch-through).

[0032] 6D, the optical monitoring device 100D receives an identification light consisting of three spectral lines. Therefore, the optical monitoring device 100D identifies that the source of this identification light is the optical device provided in the terminal station A. As a result, the optical monitoring device 100D determines that the switching states of the first optical path switching device 21 and the second optical path switching device 22 are the second switching pattern.

[0033] 7A to 7D show the spectrum of the propagation light received by the optical monitoring device 100 in the third switching pattern in which the first optical path switching device 21 is in the second switching state (branch-through) and the second optical path switching device 22 is in the first switching state (trunk-through). As shown in FIGS. 7A and 7B, the optical monitoring device 100A and the optical monitoring device 100B each receive an identification light consisting of a single spectral line. Therefore, the optical monitoring device 100A and the optical monitoring device 100B each identify that the insertion source of this identification light is the optical device provided in the terminal station C. As a result, the optical monitoring device 100A determines that the first optical path switching device 21 is in the second switching state (branch-through). On the other hand, the optical monitoring device 100B determines that the switching states of the first optical path switching device 21 and the second optical path switching device 22 are in the third switching pattern.

[0034] 8A to 8D show the spectrum of the propagation light received by the optical monitoring device 100 in the fourth switching pattern in which both the first optical path switching device 21 and the second optical path switching device 22 are in the second switching state (branch-through). As shown in FIGS. 8A and 8D, the optical monitoring device 100A and the optical monitoring device 100D each receive identification light consisting of a single spectral line. Therefore, the optical monitoring device 100A and the optical monitoring device 100D each identify that the insertion source of this identification light is the optical device provided in the terminal station C. As a result, the optical monitoring device 100A determines that the first optical path switching device 21 is in the second switching state (branch-through). On the other hand, the optical monitoring device 100D determines that the switching states of the first optical path switching device 21 and the second optical path switching device 22 are in the fourth switching pattern.

[0035] It is possible to determine the switching state of each optical path switching device by combining the identification light information (in the above example, the number of spectral lines of the ASE light that constitutes the identification light) acquired by each of the optical monitoring devices 100A to 100D. That is, for example, the optical monitoring device 100A (first optical monitoring device) generates first identification light information, which is identification light information, and the optical monitoring device 100B (second optical monitoring device) generates second identification light information, which is also identification light information. In this case, the optical monitoring device 100A (first optical monitoring device) and the optical monitoring device 100B (second optical monitoring device) can be configured to determine the switching state from at least one of the first identification light information and the second identification light information.

[0036] When the number of terminal stations increases and the number of optical monitoring devices 100 also increases, it is possible to determine the switching state of the optical route switching device in the same manner as in the above example by increasing the amount of information in the identification light information. Specifically, the amount of information in the identification light information can be increased by arranging the identification light on both the high-frequency band side and the low-frequency band side of the main signal band, or by narrowing the width of the spectral line to increase the number of spectral lines.

[0037] The optical monitoring device according to this embodiment can be configured to further include an alarm information acquisition unit (alarm information acquisition means) 140, like the optical monitoring device 101 shown in Fig. 9. The alarm information acquisition unit 140 acquires alarm information from the identification light information. Here, the alarm information acquisition unit 140 may be configured to acquire alarm information from the shape of the spectral line of the amplified spontaneous emission light that constitutes the identification light.

[0038] 10A to 10C show schematic diagrams of spectral line shapes of amplified spontaneous emission (ASE). Specifically, for example, when the spectral line shape of the ASE light is rectangular, as shown in FIG. 10A, the optical device into which the identification light is inserted can be considered to be operating normally. Furthermore, when the spectral line shape has a step, as shown in FIG. 10B and FIG. 10C, the optical device can be considered to be in a state where a first alarm or a second alarm has been issued, respectively.

[0039] Next, the optical monitoring method according to this embodiment will be described with reference to the flowchart shown in FIG.

[0040] In the optical monitoring method according to this embodiment, first, optical spectrum information of the propagating light propagating through an optical path switching device that switches the path of the signal light is generated (step S110). From this optical spectrum information, identification light information relating to the spectral form of identification light contained in the propagating light is generated (step S120). Then, from this identification light information, the switching state of the optical path switching device is determined (step S130).

[0041] As described above, the optical monitoring method according to this embodiment is configured to determine the switching state of the optical route switching device from identification light information relating to the spectrum form of the identification light contained in the propagating light. Therefore, there is no need to introduce an optical transmitter / receiver such as a transponder to determine the switching state of the optical route switching device. In other words, the optical monitoring method according to this embodiment can monitor the switching state of the branching device at the time of initial installation, even in an optical submarine cable system using the open cable method.

[0042] Here, determining the switching state may include determining that the optical path switching device is in a switching state connected to the optical device when it is determined that the identification light information indicates an optical device upstream of the optical path switching device. Determining the switching state may include determining that the optical path switching device is in a first switching state when it is determined that the identification light information indicates a first optical device among the optical devices to which the optical path switching device is connected in a first switching state. Furthermore, determining that the optical path switching device is in a second switching state when it is determined that the identification light information indicates a second optical device among the optical devices to which the optical path switching device is connected in a second switching state.

[0043] The above-mentioned propagation light is amplified spontaneous emission light added by an optical device upstream of the optical path switching device. The above-mentioned identification light is amplified spontaneous emission light having a different spectral form for each optical device. Furthermore, the above-mentioned propagation light may include modulation light in the main signal band for maintaining constant the output optical intensity of the optical device, and the identification light in an unassigned band excluding the main signal band. The above-mentioned spectral form may be at least one of the number of spectral lines of the amplified spontaneous emission light constituting the identification light, the band in which the identification light is located, and the shape of the spectral lines.

[0044] The optical monitoring method according to the present embodiment may further include acquiring alarm information from the above-described identification light information. Here, acquiring the alarm information may include acquiring the alarm information from the shape of the spectral line of the amplified spontaneous emission light that constitutes the identification light.

[0045] As described above, the optical monitoring devices 100, 101 and the optical monitoring method of this embodiment make it possible to monitor the switching state of branching devices at the time of initial installation even in an optical submarine cable system using the open cable method.

[0046] Second Embodiment Next, a second embodiment of the present invention will be described. Fig. 12 shows the configuration of an optical monitoring system 1000 according to this embodiment. The optical monitoring system 1000 comprises an optical monitoring device 1100 and an optical device 1200. The optical monitoring system 1000 is preferably used in an optical submarine cable system. In this case, the optical monitoring device 1100 can be provided in terminal station A of the optical submarine cable system 10 shown in Fig. 2, for example, and the optical device 1200 can be provided in terminal station B or terminal station C.

[0047] The optical monitoring device 1100 can be the optical monitoring device 100 according to the first embodiment. That is, the optical monitoring device 1100 includes an optical spectrum generation unit 110, an identification light information generation unit 120, and a switching state determination unit 130 (see FIG. 1).

[0048] As explained in the first embodiment, the optical monitoring device 100 is configured to determine the switching state of the optical route switching device 11 from identification light information relating to the spectrum form of identification light contained in the propagating light. Therefore, there is no need to introduce an optical transmitter / receiver such as a transponder to determine the switching state of the optical route switching device 11. In other words, the optical monitoring device 100 of this embodiment can monitor the switching state of a branching device at the time of initial installation, even in an optical submarine cable system using an open cable method.

[0049] The optical device 1200 is located in the upstream of the optical path switching device. The optical device 1200 transmits propagation light consisting of amplified spontaneous emission (ASE) light. This propagation light includes modulation light in the main signal band to maintain the output optical intensity of the optical device 1200 constant, and identification light in an unassigned band excluding the main signal band. Here, the identification light is ASE light with a spectrum shape that differs for each optical device 1200.

[0050] 13 shows the configuration of optical device 1200. Optical device 1200 has a light generation unit (light generation means) 1210 and a light control unit (light control means) 1220. Light generation unit 1210 generates amplified spontaneous emission light. Then, light control unit 1220 controls the bandwidth and power of this amplified spontaneous emission light to generate propagation light.

[0051] Here, light generating unit 1210 can be configured to include an optical waveguide containing a rare earth element in its core, and an excitation laser that generates excitation light that excites the rare earth element. Specifically, for example, light generating unit 1210 can be an ASE (Amplified Spontaneous Emission) light source in which an amplifier (Erbium Doped Fiber Amplifier: EDFA) using an erbium doped fiber in the optical waveguide is in a no-input signal state.

[0052] The optical control unit 1220 can be configured to include a wavelength selective switch (WSS). The wavelength selective switch (WSS) can adjust the amount of attenuation of the power of input light for each wavelength. By configuring the wavelength selective switch (WSS) as a one-input, one-output configuration, it is possible to obtain output light with the waveform of the input light arbitrarily shaped.

[0053] A dummy light generating block provided in an optical interface device (Open Cable Interface: OCI) used in a terminal device of an open cable optical submarine cable system can be used as the optical device 1200. However, the present invention is not limited to this, and an ASE light source may be used as the optical device 1200 separately from the optical interface device (OCI).

[0054] The optical monitoring system according to this embodiment can be configured to have a first optical monitoring device 1110 and a second optical monitoring device 1120, as in the optical monitoring system 1001 shown in Fig. 14. Here, the first optical monitoring device 1110 can be provided in, for example, terminal station A of the optical submarine cable system 20 shown in Fig. 4, and the second optical monitoring device 1120 can be provided in terminal station C or terminal station D.

[0055] The first optical monitoring device 1110 generates first identification optical information, which is identification optical information. The second optical monitoring device 1120 generates second identification optical information, which is identification optical information. The first optical monitoring device 1110 and the second optical monitoring device 1120 then determine the switching state of the optical path switching device 11 from at least one of the first identification optical information and the second identification optical information.

[0056] With this configuration, even if the number of optical route switching devices increases, it is possible to determine the switching state of each optical route switching device.

[0057] Next, the optical monitoring method according to this embodiment will be described with reference to the flowchart shown in FIG.

[0058] In the optical monitoring method according to this embodiment, first, propagation light consisting of amplified spontaneous emission light is transmitted (step S210). Next, as in the optical monitoring method according to the first embodiment, optical spectrum information of the propagation light propagating through an optical path switching device that switches the path of the signal light is generated (step S110). From this optical spectrum information, identification light information relating to the spectral form of identification light contained in the propagation light is generated (step S120). Then, from this identification light information, the switching state of the optical path switching device is determined (step S130).

[0059] The above-mentioned sending of the propagating light may include generating amplified spontaneous emission light and controlling the band and power of the amplified spontaneous emission light to generate the propagating light.

[0060] The above-mentioned identification light is amplified spontaneous emission light having a spectrum form that differs for each optical device located upstream of the optical path switching device. The above-mentioned propagation light may be configured to include modulation light in the main signal band for maintaining constant the output light intensity of the optical device, and to include identification light in an unassigned band excluding the main signal band.

[0061] The optical monitoring method according to this embodiment can also be configured to generate first identification light information, which is identification light information, generate second identification light information, which is identification light information, and determine the switching state from at least one of the first identification light information and the second identification light information.

[0062] As described above, the optical monitoring systems 1000, 1001 and optical monitoring method of this embodiment make it possible to monitor the switching state of branching devices at the time of initial installation, even in an optical submarine cable system using the open cable method.

[0063] A part or all of the above-described embodiments can be described as, but not limited to, the following supplementary notes.

[0064] (Supplementary Note 1) An optical monitoring device having an optical spectrum generating means for generating optical spectrum information of propagating light propagating through an optical path switching device that switches the path of signal light, an identification light information generating means for generating, from the optical spectrum information, identification light information relating to the spectrum form of identification light contained in the propagating light, and a switching state determining means for determining, from the identification light information, the switching state of the optical path switching device.

[0065] (Appendix 2) The optical monitoring device according to Appendix 1, wherein the switching state determination means determines that the optical path switching device is in a switching state in which it is connected to the optical device when it determines that the identification light information indicates an optical device upstream of the optical path switching device.

[0066] (Supplementary Note 3) The optical monitoring device according to Supplementary Note 2, wherein the switching state determination means determines that the optical path switching device is in the first switching state when it determines that the identification light information indicates a first optical device, among the optical devices, to which the optical path switching device is connected in a first switching state, and determines that the optical path switching device is in the second switching state when it determines that the identification light information indicates a second optical device, among the optical devices, to which the optical path switching device is connected in a second switching state.

[0067] (Appendix 4) An optical monitoring device according to appendix 1, wherein the propagation light is amplified spontaneous emission light inserted in an optical device upstream of the optical path switching device, and the identification light is amplified spontaneous emission light having a spectrum form that differs for each of the optical devices.

[0068] (Appendix 5) An optical monitoring device as described in Appendix 4, wherein the propagation light includes modulation light in a main signal band for maintaining constant output light intensity of the optical device, and includes the identification light in an unassigned band excluding the main signal band.

[0069] (Appendix 6) An optical monitoring device according to appendix 4 or 5, wherein the spectrum form is at least one of the number of spectral lines of the amplified spontaneous emission light constituting the identification light, the band in which the identification light is located, and the shape of the spectral lines.

[0070] (Supplementary Note 7) The optical monitoring device according to Supplementary Note 1, further comprising an alarm information acquiring means for acquiring alarm information from the identification light information.

[0071] (Supplementary Note 8) The optical monitoring device according to Supplementary Note 7, wherein the alarm information acquisition means acquires the alarm information from the shape of a spectral line of amplified spontaneous emission light that constitutes the identification light.

[0072] (Supplementary Note 9) An optical monitoring system comprising a first optical monitoring device which is an optical monitoring device described in any one of Supplements 1 to 8, and a second optical monitoring device which is an optical monitoring device described in any one of Supplements 1 to 8, wherein the first optical monitoring device generates first identification optical information which is the identification optical information, the second optical monitoring device generates second identification optical information which is the identification optical information, and the first optical monitoring device and the second optical monitoring device determine the switching state from at least one of the first identification optical information and the second identification optical information.

[0073] (Supplementary Note 10) An optical monitoring device according to Supplementary Note 1, and an optical device located in a front stage of the optical path switching device, wherein the optical device transmits the propagation light consisting of amplified spontaneous emission light; The identification light is the amplified spontaneous emission light having the spectrum form that differs for each of the optical devices.

[0074] (Appendix 11) An optical monitoring system as described in Appendix 10, wherein the propagation light includes adjustment light in a main signal band for maintaining constant output light intensity of the optical device, and includes the identification light in an unassigned band excluding the main signal band.

[0075] (Appendix 12) The optical monitoring system according to appendix 10 or 11, wherein the optical device comprises an optical generating means for generating the amplified spontaneous emission light, and an optical controlling means for controlling the bandwidth and power of the amplified spontaneous emission light to generate the propagating light.

[0076] (Supplementary Note 13) An optical monitoring method that generates optical spectrum information of propagating light that propagates through an optical path switching device that switches the path of signal light, generates identification light information regarding the spectral form of identification light contained in the propagating light from the optical spectrum information, and determines the switching state of the optical path switching device from the identification light information.

[0077] (Appendix 14) The optical monitoring method according to Appendix 13, wherein determining the switching state includes determining that the optical path switching device is in a switching state in which it is connected to the optical device when it is determined that the identification light information indicates an optical device upstream of the optical path switching device.

[0078] (Supplementary Note 15) The optical monitoring method according to Supplementary Note 14, wherein determining the switching state includes determining that the optical path switching device is in the first switching state when it is determined that the identification optical information indicates a first optical device among the optical devices to which the optical path switching device is connected in a first switching state, and determining that the optical path switching device is in the second switching state when it is determined that the identification optical information indicates a second optical device among the optical devices to which the optical path switching device is connected in a second switching state.

[0079] (Appendix 16) An optical monitoring method according to appendix 13, wherein the propagation light is amplified spontaneous emission light added in an optical device upstream of the optical path switching device, and the identification light is amplified spontaneous emission light having a spectrum form that differs for each of the optical devices.

[0080] (Appendix 17) An optical monitoring method according to appendix 16, wherein the propagation light includes modulation light for maintaining constant the output light intensity of the optical device in a main signal band, and includes the identification light in an unassigned band excluding the main signal band.

[0081] (Appendix 18) The optical monitoring method according to appendix 16 or 17, wherein the spectrum form is at least one of the number of spectral lines of the amplified spontaneous emission light constituting the identification light, the band in which the identification light is located, and the shape of the spectral lines.

[0082] (Supplementary Note 19) The optical monitoring method according to Supplementary Note 13, further comprising acquiring alarm information from the identification optical information.

[0083] (Supplementary Note 20) The optical monitoring method according to Supplementary Note 19, wherein acquiring the alarm information includes acquiring the alarm information from the shape of a spectral line of amplified spontaneous emission light that constitutes the identification light.

[0084] (Appendix 21) An optical monitoring method described in any one of Appendices 13 to 20, which generates first identification optical information that is the identification optical information, generates second identification optical information that is the identification optical information, and determines the switching state from at least one of the first identification optical information and the second identification optical information.

[0085] (Supplementary Note 22) An optical monitoring method according to Supplementary Note 13, comprising transmitting the propagation light consisting of amplified spontaneous emission light, wherein the identification light is the amplified spontaneous emission light having the spectrum form that differs for each optical device located upstream of the optical path switching device.

[0086] (Supplementary Note 23) The propagation light includes an adjustment light for maintaining constant the output light intensity of the optical device in a main signal band, and includes the identification light in an unassigned band excluding the main signal band. 22. An optical monitoring method as described in claim 22.

[0087] (Appendix 24) The optical monitoring method according to appendix 22 or 23, wherein the transmitting of the propagation light includes generating the amplified spontaneous emission light and controlling the bandwidth and power of the amplified spontaneous emission light to generate the propagation light.

[0088] Although the present invention has been described above with reference to the embodiments, the present invention is not limited to the above embodiments. Various modifications that can be understood by those skilled in the art can be made to the configuration and details of the present invention within the scope of the present invention. [Explanation of symbols]

[0089] 100, 101, 1100 optical monitoring equipment 110 Optical spectrum generation unit 120 Identification light information generation unit 130 Switching state determination unit 140 Alarm information acquisition unit 1000, 1001 Optical Monitoring System 1110 First optical monitoring device 1120 Second Optical Monitoring Device 1200 Optical equipment 1210 Light generation section 1220 Optical control unit 10, 20 Optical submarine cable system 11 Optical Route Switching Device 12 Optical repeater 21 First optical path switching device 22 Second optical path switching device

Claims

1. an optical spectrum generating unit that generates optical spectrum information of propagation light that propagates through an optical path switching device that switches the path of signal light; an identification light information generating means for generating, from the optical spectrum information, identification light information relating to the spectral form of identification light contained in the propagating light; a switching state determining means for determining a switching state of the optical path switching device based on the identification light information; and an alarm information acquisition means for acquiring alarm information from the identification light information. Optical monitoring device.

2. The switching state determination means If it is determined that the identification light information indicates an optical device upstream of the optical path switching device, it is determined that the optical path switching device is in a switching state for connection with the optical device.

2. An optical monitoring device according to claim 1.

3. The switching state determination means if it is determined that the identification light information indicates a first optical device among the optical devices to which the optical path switching device is connected in a first switching state, it is determined that the optical path switching device is in the first switching state; If it is determined that the identification light information indicates a second optical device among the optical devices to which the optical path switching device is connected in a second switching state, it is determined that the optical path switching device is in the second switching state.

3. An optical monitoring device according to claim 2.

4. the propagation light is amplified spontaneous emission light added by an optical device upstream of the optical path switching device, The identification light is the amplified spontaneous emission light having the spectrum form that differs for each of the optical devices.

2. An optical monitoring device according to claim 1.

5. The propagating light is The main signal band includes modulation light for maintaining constant output light intensity of the optical device, and the identification light is included in an unassigned band other than the main signal band.

5. An optical monitoring device according to claim 4.

6. The spectral form is at least one of the number of spectral lines of the amplified spontaneous emission light constituting the identification light, the band in which the identification light is located, and the shape of the spectral lines.

6. An optical monitoring device according to claim 4 or 5.

7. The alarm information acquisition means acquires the alarm information from the shape of the spectral line of the amplified spontaneous emission light that constitutes the identification light.

7. An optical monitoring device according to claim 6.

8. A first optical monitoring device, which is the optical monitoring device according to any one of claims 1 to 7; a second optical monitoring device which is the optical monitoring device according to any one of claims 1 to 7; the first optical monitoring device generates first identification light information, which is the identification light information; the second optical monitoring device generates second identification optical information, which is the identification optical information; The first optical monitoring device and the second optical monitoring device determine the switching state from at least one of the first identification light information and the second identification light information. Optical surveillance system.

9. generating optical spectrum information of the propagation light propagating through an optical path switching device that switches the path of the signal light; generating, from the optical spectrum information, identification light information relating to the spectral form of identification light included in the propagating light; Alarm information is acquired from the identification light information, and a switching state of the optical route switching device is determined. Optical monitoring method.

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