Optical branching and coupling device, optical seabed cable system, and optical branching and coupling method

Abstract

To provide an optical branching and coupling device having a configuration that can be shared among different types of optical branching and coupling devices.SOLUTION: An optical branching and coupling device includes an integrated OADM circuit and an optical input and output circuit detachably connected to the integrated OADM circuit. The integrated OADM circuit generates a third optical signal addressed to a second terminal station and a fourth optical signal addressed to a third terminal station from a first optical signal input from a first terminal station and a second optical signal input from the optical input and output circuit, outputs the fourth optical signal to the optical input and output circuit, generates a seventh optical signal addressed to the first terminal station and an eighth optical signal addressed to the third terminal station from a fifth optical signal input from the second terminal station and a sixth optical signal input from the optical input and output circuit, and outputs the eighth optical signal to the optical input and output circuit. The optical input and output circuit generates a second optical signal and a sixth optical signal from an optical signal input from the third terminal station, outputs the second optical signal and the sixth optical signal to the integrated OADM circuit, combines the fourth optical signal and the eighth optical signal, and outputs to the third terminal station.SELECTED DRAWING: Figure 2

Description

[Technical field]

[0001] The present disclosure relates to an optical branching and coupling device, an optical submarine cable system, and an optical branching and coupling method. [Background technology]

[0002] In an optical submarine cable system, an optical branching / coupling device may be installed on the seabed. A typical optical branching / coupling device, for example, multiplexes and demultiplexes optical signals received from optical submarine cables connected in three directions, and generates optical signals corresponding to the destinations of each optical signal. The generated optical signals are sent to the optical submarine cables connected to the respective destinations. In relation to the present disclosure, Patent Documents 1 and 2 describe optical branching / coupling devices having the above-mentioned functions. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] International Publication No. 2018 / 079445 [Patent Document 2] International Publication No. 2022 / 064913 Summary of the Invention [Problem to be solved by the invention]

[0004] 8 is a diagram showing the configuration of a general optical submarine cable system 8000. The optical submarine cable system 8000 includes a terminal station 81, a terminal station 82, a terminal station 83, and an optical branching / coupling device 800. The terminal stations 81-83 are all terminal stations installed on land. The terminal stations 81-83 are connected to the optical branching / coupling device 800 via optical fibers 85-88, respectively. The optical fibers 85-88 are included in the optical submarine cable.

[0005] The optical branching / coupling device 800 is a node equipped with an OADM (optical add / drop multiplexing) function, and is also called an OADM node. The optical branching / coupling device 800 is installed on the seabed, and generates an optical signal according to the output destination by splitting and multiplexing the input optical signal for each wavelength. The optical branching / coupling device 800 is, for example, the optical branching / coupling device described in Patent Document 1.

[0006] The terminal station 81 transmits a WDM (wavelength division multiplexing) signal including an optical signal

[12] and an optical signal

[13] to the optical branching / coupling device 800. The terminal stations of the source and destination of the optical signal are indicated in parentheses. For example, the optical signal

[12] is an optical signal transmitted from the terminal station 81 to the terminal station 82, and the optical signal

[13] is an optical signal transmitted from the terminal station 81 to the terminal station 83. The terminal station 83 receives the optical signal

[13] transmitted by the terminal station 81 from the optical branching / coupling device 800. The terminal station 83 transmits an optical signal

[32] destined for the terminal station 82 to the optical branching / coupling device 800. The terminal station 82 receives the optical signal

[12]

[32] , which is a multiplex of the optical signal

[12] transmitted by the terminal station 81 and the optical signal

[32] transmitted by the terminal station 83, from the optical branching / coupling device 100. The optical signal

[12]

[32] is a WDM signal, and the wavelength bands of the optical signal

[12] and the optical signal

[32] do not overlap.

[0007] With this configuration, the optical branching / coupling device 800 transmits the optical signal

[13] to the terminal station 83 and transmits the optical signal

[12] and the optical signal

[32] to the terminal station 82.

[0008] FIG. 9 is a diagram showing the configuration of a general optical submarine cable system 8001. The optical submarine cable system 8001 includes an optical branching and coupling device 810 and terminal stations 81-83. The optical branching and coupling device 810 includes optical branching and coupling devices 801 and 802. The optical branching and coupling device 810 enables bidirectional transmission between the terminal station 81 and the terminal station 82 using the optical branching and coupling devices 801 and 802. The configurations of the optical branching and coupling devices 801 and 802 are the same as those of the optical branching and coupling device 800, and only the terminal stations 81-83 to which optical signals are input and output are different. The optical branching and coupling device 810 having such a configuration can transmit optical signals bidirectionally between each of the terminal stations 81-83. The optical branching and coupling device 810 includes two optical branching and coupling devices 801 and 802. Therefore, the optical submarine cable 24 connecting the terminal station 83 and the optical branching and coupling device 810 requires four optical fibers.

[0009] Fig. 10 is a diagram showing the configuration of a typical optical submarine cable system 8002. The optical submarine cable system 8002 comprises terminal station 91, terminal station 92, terminal station 93, and optical branching / coupling device 900. Terminal stations 91-93 perform bidirectional communication. All of terminal stations 91-93 are terminal stations installed on land. Terminal stations 91-93 and optical branching / coupling device 900 are connected by optical submarine cables 95-97, respectively. Each of optical submarine cables 95-97 comprises two optical fibers.

[0010] The optical branching / coupling device 900 is, for example, the optical branching / coupling device described in Patent Document 2. The terminal station 91 outputs an optical signal

[12]

[13] to the optical branching / coupling device 900. The terminal station 92 outputs an optical signal

[21]

[23] to the optical branching / coupling device 900. The terminal station 93 outputs an optical signal

[31]

[32] to the optical branching / coupling device 900. The optical signal

[12] is an optical signal transmitted from the terminal station 91 to the terminal station 92, and the optical signal

[21] is an optical signal transmitted from the terminal station 92 to the terminal station 91. The optical signal

[12]

[13] is a WDM signal in which the optical signal

[12] and the optical signal

[13] are wavelength-multiplexed.

[0011] The optical branching / coupling device 900 receives optical signals

[12]

[13] , optical signals

[21]

[23] , and optical signals

[31]

[32] from the terminal stations 91-93, respectively. The optical branching / coupling device 900 splits and combines these received optical signals for each wavelength band. Specifically, the optical branching / coupling device 900 outputs the optical signal

[12]

[32] to the terminal station 92. The optical signal

[12]

[32] is a WDM signal in which the optical signal

[12] and the optical signal

[32] are wavelength-multiplexed. The optical branching / coupling device 900 similarly generates an optical signal

[13]

[23] and outputs it to the terminal station 93, and generates an optical signal

[21]

[31] and outputs it to the terminal station 91.

[0012] With this configuration, the optical branching / coupling device 900 realizes two-way communication between the terminal stations 91 to 93. In the optical submarine cable system 8002, the optical submarine cable 97 connecting the terminal station 93 and the optical branching / coupling device 900 requires two optical fibers.

[0013] Both the optical branching and coupling device 810 and the optical branching and coupling device 900 can be used as OADM nodes in an optical submarine cable system. However, the optical branching and coupling device 810 and the optical branching and coupling device 900 have different connection forms with the terminal station 83 or the terminal station 93. That is, the optical branching and coupling device 810 and the terminal station 83 are connected by four optical fibers, whereas the optical branching and coupling device 900 and the terminal station 93 are connected by only two optical fibers.

[0014] In this way, the optical branching and coupling devices 810 and 900 differ in the number of optical fibers required for connection to the terminal station 83 or 93 and the number of optical fibers required for connection to the terminal station 93. For this reason, in an optical submarine cable system in which the optical branching and coupling devices 810 and 900 are used together, it is not possible to share a spare optical branching and coupling device with either one of the devices. That is, in this case, it is necessary to prepare both the optical branching and coupling device 810 and the optical branching and coupling device 900 as spare optical branching and coupling devices. This may lead to a decrease in efficiency and an increase in costs in the manufacture and management of devices used in the optical submarine cable system and in the storage of spare devices.

[0015] (Objective of the Invention) An object of the present disclosure is to provide a technique for configuring an optical branching / coupling device having a configuration that can be shared among optical branching / coupling devices of different types. [Means for solving the problem]

[0016] An optical branching / coupling device according to the present disclosure is an optical branching / coupling device used in an optical submarine cable system, An integrated OADM circuit and an optical input / output circuit configured to be detachable from the integrated OADM circuit, The integrated OADM circuit comprises: generating a third optical signal destined for the second terminal station and a fourth optical signal destined for the third terminal station from a first optical signal input from a first terminal station and a second optical signal input from the optical input / output circuit, and outputting the fourth optical signal to the optical input / output circuit; generating a seventh optical signal destined for the first terminal station and an eighth optical signal destined for the third terminal station from a fifth optical signal input from the second terminal station and a sixth optical signal input from the optical input / output circuit, and outputting the eighth optical signal to the optical input / output circuit; The optical input / output circuit generates the second optical signal and the sixth optical signal from the optical signal input from the third terminal station, outputs the second optical signal and the sixth optical signal to the integrated OADM circuit, and combines the fourth optical signal and the eighth optical signal and outputs the combined signal to the third terminal station.

[0017] The optical branching and coupling method according to the present disclosure is an optical branching and coupling method for an optical branching and coupling device for use in an optical submarine cable system, the optical branching and coupling device comprising an integrated OADM circuit and an optical input / output circuit configured to be detachable from the integrated OADM circuit, the optical branching and coupling method comprising: In the integrated OADM circuit, generating a third optical signal destined for the second terminal station and a fourth optical signal destined for the third terminal station from a first optical signal input from a first terminal station and a second optical signal input from the optical input / output circuit; outputting the fourth optical signal to the optical input / output circuit; generating a seventh optical signal destined for the first terminal station and an eighth optical signal destined for the third terminal station from a fifth optical signal input from the second terminal station and a sixth optical signal input from the optical input / output circuit; outputting the eighth optical signal to the optical input / output circuit; In the optical input / output circuit, generating the second optical signal and the sixth optical signal from an optical signal input from the third terminal station; outputting the second optical signal and the sixth optical signal to the integrated OADM circuit; combining the fourth optical signal and the eighth optical signal and outputting the combined signal to the third terminal station; Includes instructions. Effect of the Invention

[0018] The present disclosure makes it possible to provide an optical branching / coupling device having a configuration that can be shared between optical branching / coupling devices of different types. [Brief description of the drawings]

[0019] [Figure 1] FIG. 1 is a diagram illustrating an example of the configuration of an optical submarine cable system. [Diagram 2] FIG. 1 is a diagram illustrating a configuration example of an optical branching / coupling device. [Diagram 3] FIG. 2 is a diagram illustrating a detailed configuration example of an OADM circuit. [Figure 4] FIG. 2 is a diagram illustrating a detailed configuration example of an OADM circuit. [Diagram 5] FIG. 1 is a diagram illustrating an example of the configuration of an optical submarine cable system. [Figure 6] FIG. 1 is a diagram illustrating an example of the configuration of an optical submarine cable system. [Figure 7] FIG. 1 is a diagram illustrating a configuration example of an optical branching / coupling device. [Figure 8] FIG. 1 is a diagram illustrating a configuration of a typical optical submarine cable system. [Figure 9] FIG. 1 is a diagram illustrating a configuration of a typical optical submarine cable system. [Figure 10] FIG. 1 is a diagram illustrating a configuration of a typical optical submarine cable system. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0020] An embodiment of the present disclosure will be described below with reference to the drawings. Arrows shown in the drawings are intended to illustrate the direction of signals, etc., and are not intended to limit the direction and nature of signals, etc. In addition, in the embodiments and drawings, elements that have already been mentioned may be given the same reference numerals, and duplicated descriptions may be omitted.

[0021] (First embodiment) FIG. 1 is a diagram showing an example of the configuration of an optical submarine cable system 1000. The optical submarine cable system 1000 includes an optical branching / coupling device 100 and terminal stations 1-3. The terminal stations 1-3 are connected to the optical branching / coupling device 100 by optical submarine cables 21-23, respectively. The optical branching / coupling device 100 is installed on the seabed. The terminal stations 1-3 are all terminal stations installed on land. The terminal stations 1-3 are an interface between the optical submarine cable system 1000 and a land network system. The terminal stations 1 and 2 may be trunk stations, and the terminal station 3 may be a branch station.

[0022] The optical branching / coupling device 100 and the terminal stations 1-3 are connected to each other so as to be able to communicate with each other via optical submarine cables 21-23. Each of the optical submarine cables 21-23 includes an optical fiber and a power feeder. Each of the optical submarine cables 21-23 transmits optical signals in both directions by two optical fibers that transmit optical signals in different directions. The power feeder is used to feed power from the terminal stations 1-3 to the optical branching / coupling device 100. In this embodiment and the following embodiments, a description of the power feeder will be omitted.

[0023] The terminal station 1 transmits an optical signal

[12]

[13] including an optical signal

[12] and an optical signal

[13] to the optical branching / coupling device 100. The optical signal

[12] is an optical signal transmitted from the terminal station 1 to the terminal station 2, and the optical signal

[13] is an optical signal transmitted from the terminal station 1 to the terminal station 3. The terminal station 1 also receives an optical signal

[21]

[31] from the optical branching / coupling device 100. Here, for example, the optical signal

[12]

[13] is an optical signal in which the optical signal

[12] and the optical signal

[13] are wavelength-multiplexed. A wavelength-multiplexed optical signal is also called a WDM (wavelength division multiplexing) signal. In this embodiment and the following embodiments, the wavelength bands of the optical signals included in one WDM signal are set so as not to overlap. For example, in the optical signal

[12]

[13] , the wavelength bands of the optical signal

[12] and the optical signal

[13] do not overlap.

[0024] Similarly, the terminal station 2 transmits an optical signal

[21]

[23] to the optical branching / coupling device 100 and receives an optical signal

[12]

[32] from the optical branching / coupling device 100. The terminal station 3 transmits an optical signal

[31]

[32] to the optical branching / coupling device 100 and receives an optical signal

[13]

[23] from the optical branching / coupling device 100.

[0025] 2 is a diagram showing an example of the configuration of the optical branching / coupling device 100. The optical branching / coupling device 100 includes an integrated OADM circuit 10 and an optical input / output circuit 130 that is configured to be detachable from the integrated OADM circuit 10.

[0026] The integrated OADM circuit 10 includes OADM circuits 110 and 120. The OADM circuit 110 multiplexes / demultiplexes an optical signal

[12]

[13] received from the terminal station 1 and an optical signal

[31]

[32] received from the optical input / output circuit 130 to generate an optical signal

[12]

[32] and an optical signal

[13] . The OADM circuit 110 transmits the optical signal

[12]

[32] to the terminal station 2 and transmits the optical signal

[13] to the optical input / output circuit 130.

[0027] The OADM circuit 120 multiplexes / demultiplexes the optical signal

[21]

[23] received from the terminal station 2 and the optical signal

[31]

[32] received from the optical input / output circuit 130 to generate the optical signal

[21]

[31] and the optical signal

[23] . The OADM circuit 120 transmits the optical signal

[21]

[31] to the terminal station 1, and transmits the optical signal

[23] to the optical input / output circuit 130.

[0028] The optical input / output circuit 130 is disposed between the integrated OADM circuit 10 and the terminal station 3. The housing of the optical input / output circuit 130 and the optical transmission path are detachable from the housing of the integrated OADM circuit 10 and the optical transmission path. For example, the housing of the integrated OADM circuit 10 and the housing of the optical input / output circuit 130 may be fixed with connecting members such as screws, and the housings may be separated by removing the screws. Also, the optical transmission path between the integrated OADM circuit 10 and the optical input / output circuit 130 may be configured to be connectable and disconnectable by an optical connector.

[0029] The optical input / output circuit 130 includes optical couplers 131 and 132. The optical couplers 131 and 132 are, for example, 1×2 optical couplers. The optical coupler 131 splits an optical signal

[31]

[32] received from the terminal station 3 into two, and transmits one to the OADM circuit 110 and the other to the OADM circuit 120. The optical coupler 132 combines the optical signal

[13] received from the OADM circuit 110 and the optical signal

[23] received from the OADM circuit 120, and transmits the optical signal

[13]

[23] generated by the combination to the terminal station 3. The optical couplers 131 and 132 can be called the first optical coupler and the second optical coupler, respectively.

[0030] The configuration of the OADM circuit 110 will be described in more detail. The OADM circuit 110 has a first terminal 111, a second terminal 112, a third terminal 113, and a fourth terminal 114. An optical signal

[12]

[13] transmitted by the terminal station 1 is input to the first terminal 111. An optical signal

[31]

[32] transmitted by the optical input / output circuit 130 is input to the second terminal 112.

[0031] The OADM circuit 110 multiplexes and splits the optical signal

[12]

[13] input from the first terminal 111 and the optical signal

[31]

[32] input from the second terminal 112 to generate the optical signal

[12]

[32] and the optical signal

[13] . The optical signal

[12]

[32] is transmitted from the third terminal 113 to the terminal station 2. The optical signal

[13] is transmitted from the fourth terminal 114 to the optical input / output circuit 130. The first to fourth terminals 111-114 are input / output points of the optical signal of the OADM circuit 110, that is, optical connection points between the OADM circuit 110 and the optical transmission line. The optical connection points are, for example, optical connectors or fusion splicing points of optical fibers, but are not limited thereto.

[0032] The OADM circuit 110 and the OADM circuit 120 differ in the optical signals input and output and the connection destinations of each terminal. However, their internal configurations are the same. That is, the OADM circuit 120 has a first terminal 121, a second terminal 122, a third terminal 123, and a fourth terminal 124. An optical signal

[21]

[23] transmitted by the terminal station 2 is input to the first terminal 121. An optical signal

[31]

[32] transmitted by the optical input / output circuit 130 is input to the second terminal 122.

[0033] The OADM circuit 110 and the OADM circuit 120 can be called a first OADM circuit and a second OADM circuit, respectively. Also, the first terminal 121, the second terminal 122, the third terminal 123, and the fourth terminal 124 of the OADM circuit 120 can be called a fifth terminal, a sixth terminal, a seventh terminal, and an eighth terminal, respectively.

[0034] The OADM circuit 120 multiplexes and demultiplexes the optical signal

[21]

[23] input from the first terminal 121 and the optical signal

[31]

[32] input from the second terminal 122 to generate the optical signal

[21]

[31] and the optical signal

[23] . The optical signal

[21]

[31] is transmitted from the third terminal 123 to the terminal station 1. The optical signal

[13] is transmitted from the fourth terminal 124 to the optical input / output circuit 130. Both of the OADM circuits 110 and 120 may multiplex or demultiplex the input optical signal using a wavelength selective switch (WSS).

[0035] Fig. 3 is a diagram showing a detailed configuration example of the OADM circuit 110. The configuration of the OADM circuit 110 shown in Fig. 3 conforms to the optical branching and coupling device described in Patent Document 1. However, the description in Fig. 3 does not limit the functions and configurations of the OADM circuits 110 and 120.

[0036] The OADM circuit 110 includes four optical couplers (CPL1101-1104), two WSSs (WSS1105-1106), and three optical switches (SW1107-1109). As described above, the first terminal 111 receives an optical signal

[12]

[13] , and the second terminal 112 receives an optical signal

[31]

[32] . One of the WSSs 1105 and 1106 generates an optical signal

[12]

[32] from these optical signals, and the other of the WSSs 1105 and 1106 generates an optical signal

[13] from these optical signals. The three optical switches 1107-1109 are controlled so that the optical signal

[12]

[32] is output from the third terminal 113 and the optical signal

[13] is output from the fourth terminal 114 according to the operating state of the WSS.

[0037] FIG. 4 is a diagram showing a detailed configuration example of the OADM circuit 120. Like the OADM circuit 110, the OADM circuit 120 also includes four optical couplers 1201-1204, two WSSs 1205 and 1206, and three optical switches 1207-1209. An optical signal

[21]

[23] is input to the first terminal 121, and an optical signal

[31]

[32] is input to the second terminal 122. One of the WSSs 1205 and 1206 generates an optical signal

[21]

[31] from these optical signals, and the other of the WSSs 1205 and 1206 generates an optical signal

[23] from these optical signals. The three optical switches 1207-1209 are controlled to output the optical signal

[21]

[31] from the third terminal 123 and the optical signal

[23] from the fourth terminal 124 according to the operating state of the WSS.

[0038] Regardless of the configuration in Fig. 3, the OADM circuit 110 may have a configuration capable of realizing the following functions. That is, the OADM circuit 110 generates optical signals

[12]

[32] and

[13] from the optical signals

[12]

[13] input from the first terminal 111 and the optical signals

[31]

[32] input from the second terminal 112. Then, the OADM circuit 110 outputs the optical signals

[12]

[32] from the third terminal 113 and outputs the optical signal

[13] from the fourth terminal 114.

[0039] 4, the OADM circuit 120 may have a configuration capable of realizing the following functions. That is, the OADM circuit 120 generates optical signals

[21]

[31] and

[23] from the optical signals

[21]

[23] input from the first terminal 121 and the optical signals

[31]

[32] input from the second terminal 122. Then, the OADM circuit 120 outputs the optical signals

[21]

[31] from the third terminal 123 and outputs the optical signal

[23] from the fourth terminal 124.

[0040] The optical branching and coupling device 100 having the above configuration includes an optical input / output circuit 130 in addition to the OADM circuits 110 and 120. With such a configuration, the optical branching and coupling device 100 can simplify the connection configuration between the terminal station 3 and the OADM circuits 110 and 120. If the optical branching and coupling device 100 does not include the optical input / output circuit 130, four optical fibers are required to connect the second terminals 112, 122 and the fourth terminals 114, 124 to the terminal station 3 in order to connect the integrated OADM circuit 10 to the terminal station 3. In contrast, the optical branching and coupling device 100 can connect the optical branching and coupling device 100 to the terminal station 3 using only two optical fibers.

[0041] At least one of the optical couplers 131 and 132 included in the optical input / output circuit 130 may be an optical multiplexer / demultiplexer. For example, the optical input / output circuit 130 may include an optical demultiplexer that demultiplexes the optical signal

[31] and the optical signal

[32] instead of the optical coupler 131. In this case, the optical demultiplexer demultiplexes the optical signal

[31] and the optical signal

[32] received from the terminal station 3, and transmits the optical signal

[32] to the OADM circuit 110 and transmits the optical signal

[31] to the OADM circuit 120. Also, the optical input / output circuit 130 may include an optical multiplexer that multiplexes the optical signal

[13] and the optical signal

[23] instead of the optical coupler 132. In this case, the optical multiplexer multiplexes the optical signal

[13] received from the OADM circuit 110 and the optical signal

[23] received from the OADM circuit 120 to generate an optical signal

[13]

[23] , and transmits the optical signal to the terminal station 3.

[0042] (Another expression of the first embodiment) The configuration of the optical branching and coupling device 100 described above can also be described as follows: The reference characters in parentheses indicate the correspondence with the components shown in FIGS.

[0043] The optical branching / coupling device (100) is an optical branching / coupling device used in an optical submarine cable system (1000). The optical branching / coupling device (100) includes an integrated OADM circuit (10) and an optical input / output circuit (130) configured to be detachable from the integrated OADM circuit (10).

[0044] The integrated OADM circuit (10) receives a first optical signal (

[12]

[13] ) from the first terminal station (1) and receives a second optical signal (

[31]

[32] ) from the optical input / output circuit (130). From these input optical signals, the integrated OADM circuit (10) generates a third optical signal (

[12]

[32] ) destined for the second terminal station (2) and a fourth optical signal (

[13] ) destined for the third terminal station (3). The integrated OADM circuit (10) then outputs the fourth optical signal (

[13] ) to the optical input / output circuit (130).

[0045] In addition, the integrated OADM circuit (10) receives a fifth optical signal (

[21]

[23] ) from the second terminal station (2) and a sixth optical signal (

[31]

[32] ) from the optical input / output circuit (130). From these input optical signals, the integrated OADM circuit (10) generates a seventh optical signal (

[21]

[31] ) addressed to the first terminal station (1) and an eighth optical signal (

[23] ) addressed to the third terminal station (3). The integrated OADM circuit (10) then outputs the eighth optical signal (

[23] ) to the optical input / output circuit (130).

[0046] Furthermore, the optical input / output circuit (130) generates a second optical signal (

[31]

[32] ) and a sixth optical signal (

[31]

[32] ) from the optical signal input from the third terminal station (3). The optical input / output circuit (130) outputs the second optical signal ("31", "32") and the sixth optical signal ("31", "32") to the integrated OADM circuit (10). The optical input / output circuit (130) also combines the fourth optical signal (

[13] ) and the eighth optical signal (

[23] ) and outputs the combined signal to the third terminal station (3).

[0047] Second embodiment FIG. 5 is a diagram showing an example of the configuration of an optical submarine cable system 2000. The optical submarine cable system 2000 includes an optical branching / coupling device 200 and terminal stations 1-3. The terminal stations 1-3 are connected to the optical branching / coupling device 200 by optical submarine cables 21-23, respectively. The optical branching / coupling device described in Patent Document 2 can be applied as the optical branching / coupling device 200 shown in FIG. 5. That is, the optical branching / coupling device 200 multiplexes / demultiplexes an optical signal

[12]

[13] received from the terminal station 1, an optical signal

[21]

[23] received from the terminal station 2, and an optical signal

[31]

[32] received from the terminal station 3 to generate an optical signal to be transmitted to the terminal stations 1-3. Then, the optical branching / coupling device 200 transmits the optical signal

[21]

[31] to the terminal station 1, transmits the optical signal

[12]

[32] to the terminal station 2, and transmits the optical signal

[13]

[23] to the terminal station 3.

[0048] The function of the optical branching and coupling device 200 is similar to that of the optical branching and coupling device 100 , so that in the optical submarine cable system 2000 , the optical branching and coupling device 100 can replace the optical branching and coupling device 200 .

[0049] (Third embodiment) 6 is a diagram showing an example of the configuration of an optical submarine cable system 3000. The optical submarine cable system 3000 includes an optical branching / coupling device 300 and terminal stations 1, 2, and 4. Terminal stations 1, 2, and 4 are connected to the optical branching / coupling device 100 by optical submarine cables 21, 22, and 24, respectively. Terminal station 1, terminal station 2, and terminal station 4 are all terminal stations installed on land.

[0050] The optical branching / coupling device 300 is connected to the terminal station 1, the terminal station 2, and the terminal station 4 via optical submarine cables 21, 22, and 24 so as to be able to communicate with each other. The optical submarine cables 21 and 22 transmit optical signals in both directions using two optical fibers with different transmission directions of the optical signals. The optical submarine cable 24 transmits optical signals in both directions between the optical branching / coupling device 300 and the terminal station 4 using four optical fibers.

[0051] The format of the optical signals transmitted and received between terminal station 1 and terminal station 2 is the same as that of the optical submarine cable system 1000. That is, terminal station 1 transmits an optical signal

[12]

[14] to the optical branching / coupling device 500 and receives an optical signal

[21]

[41] from the optical branching / coupling device 100. Terminal station 2 transmits an optical signal

[21]

[24] to the optical branching / coupling device 500 and receives an optical signal

[12]

[42] from the optical branching / coupling device 500.

[0052] On the other hand, in the optical submarine cable system 3000, the optical branching / coupling device 300 and the terminal station 4 are connected by four optical fibers. This configuration may be adopted when the terminal station 4 does not have the function of wavelength multiplexing the optical signals transmitted and received between the optical branching / coupling device 300, or when the optical submarine cable 24 has a sufficient number of optical fibers. In the optical submarine cable system 3000, the four optical fibers between the optical branching / coupling device 300 and the terminal station 4 transmit the optical signal

[41] , the optical signal

[42] , the optical signal

[14] , and the optical signal

[24] , respectively.

[0053] Fig. 7 is a diagram showing a configuration example of an optical branching and coupling device 300. The optical branching and coupling device 300 includes OADM circuits 110 and 120. That is, the optical branching and coupling device 300 has the same configuration as the integrated OADM circuit 10 described in Fig. 2. In other words, the optical branching and coupling device 300 is the optical branching and coupling device 100 without the optical input / output circuit 130. Since the optical input / output circuit 130 is detachable from the integrated OADM circuit 10, the integrated OADM circuit 10 can be used as a standalone optical branching and coupling device 300.

[0054] The configuration and operation of the optical branching / coupling device 300 are similar to those of the integrated OADM circuit 10. In this embodiment, the OADM circuit 110 multiplexes / demultiplexes the optical signal

[12]

[14] received from the terminal station 1 and the optical signal

[42] received from the terminal station 4 to generate the optical signal

[12]

[42] and the optical signal

[14] . The OADM circuit 110 transmits the optical signal

[12]

[42] to the terminal station 2 and transmits the optical signal

[14] to the terminal station 4.

[0055] The OADM circuit 120 multiplexes / demultiplexes the optical signal

[21]

[24] received from the terminal station 2 and the optical signal

[41] received from the terminal station 4 to generate the optical signal

[21]

[41] and the optical signal

[24] . The OADM circuit 120 transmits the optical signal

[21]

[41] to the terminal station 1 and transmits the optical signal

[24] to the terminal station 4.

[0056] In the optical branching / coupling device 100, the integrated OADM circuit 10 and the optical input / output circuit 130 are configured to be detachable. Therefore, by removing the optical input / output circuit 130 from the optical branching / coupling device 100, the integrated OADM circuit 10 can be used as an optical branching / coupling device 300 including the OADM circuits 110 and 120. The optical branching / coupling device 300 is connected to the terminal station 4 by different optical fibers for the optical signal

[41] , the optical signal

[42] , the optical signal

[14] , and the optical signal

[24] . In this way, the integrated OADM circuit 10 can replace the existing optical branching / coupling device 300 in the optical submarine cable system 3000 illustrated in FIG. 6. The existing optical branching / coupling device 300 is, for example, a device including the OADM circuits 110 and 120 described in FIG. 3 and FIG. 4.

[0057] In an optical submarine cable system in which the optical branching and coupling device 200 shown in Fig. 5 and the optical branching and coupling device 300 shown in Fig. 6 are used together, it was necessary to secure two types of devices, the optical branching and coupling device 300 and the optical branching and coupling device 200, for maintenance of the optical branching and coupling devices. However, the optical branching and coupling device 100 of this embodiment includes an integrated OADM circuit 10 and a detachable optical input / output circuit 130, and therefore can be replaced with either the optical branching and coupling device 200 or the optical branching and coupling device 300. Therefore, in an optical submarine cable system in which the optical branching and coupling device 200 and the optical branching and coupling device 300, which have different forms, are used together, the optical branching and coupling device 100 can be used as a common spare device.

[0058] In addition, the embodiment of the present disclosure can be described as follows, but is not limited to the following.

[0059] (Appendix 1) An optical branching and coupling device for use in an optical submarine cable system, comprising: An integrated OADM circuit and an optical input / output circuit configured to be detachable from the integrated OADM circuit, The integrated OADM circuit comprises: generating a third optical signal destined for the second terminal station and a fourth optical signal destined for the third terminal station from a first optical signal input from a first terminal station and a second optical signal input from the optical input / output circuit, and outputting the fourth optical signal to the optical input / output circuit; generating a seventh optical signal destined for the first terminal station and an eighth optical signal destined for the third terminal station from a fifth optical signal input from the second terminal station and a sixth optical signal input from the optical input / output circuit, and outputting the eighth optical signal to the optical input / output circuit; the optical input / output circuit generates the second optical signal and the sixth optical signal from the optical signal input from the third terminal station, outputs the second optical signal and the sixth optical signal to the integrated OADM circuit, and combines the fourth optical signal and the eighth optical signal and outputs the combined signal to the third terminal station. Optical branching and coupling device.

[0060] (Appendix 2) the integrated OADM circuit comprises a first OADM circuit and a second OADM circuit; the first OADM circuit generates the third optical signal and the fourth optical signal from the first optical signal input from a first terminal and the second optical signal input from the optical input / output circuit connected to a second terminal, outputs the third optical signal from a third terminal, and outputs the fourth optical signal from a fourth terminal to the optical input / output circuit; the second OADM circuit generates the seventh optical signal and the eighth optical signal from the fifth optical signal input from a fifth terminal and the sixth optical signal input from the optical input / output circuit connected to a sixth terminal, outputs the seventh optical signal from a seventh terminal, and outputs the eighth optical signal to the optical input / output circuit. 2. An optical splitter / coupler as described in appendix 1.

[0061] (Appendix 3) 3. An optical branching and coupling device as described in appendix 1 or 2, wherein the optical input / output circuit includes a first optical coupler that branches an input optical signal and a second optical coupler that combines the two input optical signals, and connects between the integrated OADM circuit and the third terminal station.

[0062] (Appendix 4) 4. An optical branching and coupling device as described in Appendix 3, wherein the first optical coupler generates the second optical signal and the sixth optical signal from the optical signal input from the third terminal station, and the second optical coupler combines the fourth optical signal and the eighth optical signal.

[0063] (Appendix 5) 5. The optical branching / coupling device according to claim 3, wherein at least one of the first optical coupler and the second optical coupler is an optical multiplexer / demultiplexer.

[0064] (Appendix 6) 6. The optical branching and coupling device according to claim 1, wherein the integrated OADM circuit comprises a wavelength selective switch.

[0065] (Appendix 7) An optical branching / coupling device according to any one of claims 1 to 6, the first terminal station to the third terminal station; An optical submarine cable system comprising:

[0066] (Appendix 8) 8. The optical submarine cable system according to claim 7, wherein the first terminal station and the second terminal station are trunk stations, and the third terminal station is a branch station.

[0067] (Appendix 9) An optical branching and coupling method for an optical branching and coupling device for use in an optical submarine cable system, comprising an integrated OADM circuit and an optical input / output circuit configured to be detachable from the integrated OADM circuit, comprising: In the integrated OADM circuit, generating a third optical signal destined for the second terminal station and a fourth optical signal destined for the third terminal station from a first optical signal input from a first terminal station and a second optical signal input from the optical input / output circuit; outputting the fourth optical signal to the optical input / output circuit; generating a seventh optical signal destined for the first terminal station and an eighth optical signal destined for the third terminal station from a fifth optical signal input from the second terminal station and a sixth optical signal input from the optical input / output circuit; outputting the eighth optical signal to the optical input / output circuit; In the optical input / output circuit, generating the second optical signal and the sixth optical signal from an optical signal input from the third terminal station; outputting the second optical signal and the sixth optical signal to the integrated OADM circuit; combining the fourth optical signal and the eighth optical signal and outputting the combined signal to the third terminal station; Optical branching and coupling method.

[0068] (Appendix 10) using a first OADM circuit included in the integrated OADM circuit, generating the third optical signal and the fourth optical signal from the first optical signal input from a first terminal and the second optical signal input from the optical input / output circuit connected to a second terminal, outputting the third optical signal from a third terminal, and outputting the fourth optical signal from a fourth terminal to the optical input / output circuit; using a second OADM circuit included in the integrated OADM circuit, generating the seventh optical signal and the eighth optical signal from the fifth optical signal input from a fifth terminal and the sixth optical signal input from the optical input / output circuit connected to a sixth terminal, outputting the seventh optical signal from a seventh terminal, and outputting the eighth optical signal to the optical input / output circuit; 10. An optical branching and coupling method as described in Supplementary Note 9.

[0069] (Appendix 11) 11. The optical branching and coupling method according to claim 9 or 10, wherein the integrated OADM circuit and the third terminal station are connected using a first optical coupler that branches an input optical signal and a second optical coupler that combines two input optical signals, both of which are provided in the optical input / output circuit.

[0070] (Appendix 12) generating the second optical signal and the sixth optical signal from an optical signal input from the third terminal station using the first optical coupler; combining the fourth optical signal and the eighth optical signal using the second optical coupler; 12. An optical branching and coupling method according to claim 11.

[0071] Although the present disclosure has been described above with reference to the embodiments, the present disclosure 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 disclosure within the scope of the present disclosure. For example, the present disclosure can be applied not only to optical submarine cable systems but also to terrestrial optical transmission systems. In addition, the description of the optical branching and coupling device in each embodiment also discloses the configuration of an optical submarine cable system including the optical branching and coupling device and a terminal station connected thereto, and an optical branching and coupling method in the optical branching and coupling device.

[0072] In addition, the configurations described in the respective embodiments are not necessarily mutually exclusive. The actions and effects of the present disclosure may be achieved by a configuration that combines all or part of the above-described embodiments. [Explanation of symbols]

[0073] 10 Integrated OADM circuits 21-24, 95-97 Optical Submarine Cable 1-4, 81-83, 91-93 terminal station 85-88 Optical Fiber 110, 120 OADM circuit 111, 121 1st terminal 112, 122 Second terminal 113, 123 Third terminal 114, 124 4th terminal 130 Optical input / output circuit 131-132 Optical Coupler 100, 200, 300, 500 Optical splitter / coupler 800-802, 810, 900 Optical splitter / coupler 1000, 2000, 3000 Optical Submarine Cable Systems 8000-8002 Optical Submarine Cable System

Claims

1. An optical branching and coupling device for use in an optical submarine cable system, comprising: An integrated OADM circuit and an optical input / output circuit configured to be detachable from the integrated OADM circuit, The integrated OADM circuit includes: generating a third optical signal destined for the second terminal station and a fourth optical signal destined for the third terminal station from a first optical signal input from a first terminal station and a second optical signal input from the optical input / output circuit, and outputting the fourth optical signal to the optical input / output circuit; generating a seventh optical signal destined for the first terminal station and an eighth optical signal destined for the third terminal station from a fifth optical signal input from the second terminal station and a sixth optical signal input from the optical input / output circuit, and outputting the eighth optical signal to the optical input / output circuit; the optical input / output circuit generates the second optical signal and the sixth optical signal from the optical signal input from the third terminal station, outputs the second optical signal and the sixth optical signal to the integrated OADM circuit, and combines the fourth optical signal and the eighth optical signal and outputs the combined signal to the third terminal station. Optical branching and coupling device.

2. the integrated OADM circuit comprises a first OADM circuit and a second OADM circuit; the first OADM circuit generates the third optical signal and the fourth optical signal from the first optical signal input from a first terminal and the second optical signal input from the optical input / output circuit connected to a second terminal, outputs the third optical signal from a third terminal, and outputs the fourth optical signal from a fourth terminal to the optical input / output circuit; the second OADM circuit generates the seventh optical signal and the eighth optical signal from the fifth optical signal input from a fifth terminal and the sixth optical signal input from the optical input / output circuit connected to a sixth terminal, outputs the seventh optical signal from a seventh terminal, and outputs the eighth optical signal to the optical input / output circuit.

2. An optical branching and coupling device according to claim 1.

3. 3. The optical branching and coupling device according to claim 1, wherein the optical input / output circuit comprises a first optical coupler that branches an input optical signal and a second optical coupler that combines two input optical signals, and connects between the integrated OADM circuit and the third terminal station.

4. 4. The optical branching and coupling device according to claim 3, wherein the first optical coupler generates the second optical signal and the sixth optical signal from the optical signal input from the third terminal station, and the second optical coupler combines the fourth optical signal and the eighth optical signal.

5. 4. The optical branching / coupling device according to claim 3, wherein at least one of the first optical coupler and the second optical coupler is an optical multiplexer / demultiplexer.

6. 3. The optical branching / coupling device according to claim 1, wherein the integrated OADM circuit comprises a wavelength selective switch.

7. An optical branching / coupling device according to claim 1 or 2; the first terminal station to the third terminal station; An optical submarine cable system comprising:

8. 8. The optical submarine cable system according to claim 7, wherein said first terminal station and said second terminal station are trunk stations, and said third terminal station is a branch station.

9. 1. An optical branching and coupling method for an optical branching and coupling device for use in an optical submarine cable system, comprising an integrated OADM circuit and an optical input / output circuit configured to be detachable from the integrated OADM circuit, comprising: In the integrated OADM circuit, generating a third optical signal destined for the second terminal station and a fourth optical signal destined for the third terminal station from a first optical signal input from a first terminal station and a second optical signal input from the optical input / output circuit; outputting the fourth optical signal to the optical input / output circuit; generating a seventh optical signal destined for the first terminal station and an eighth optical signal destined for the third terminal station from a fifth optical signal input from the second terminal station and a sixth optical signal input from the optical input / output circuit; outputting the eighth optical signal to the optical input / output circuit; In the optical input / output circuit, generating the second optical signal and the sixth optical signal from an optical signal input from the third terminal station; outputting the second optical signal and the sixth optical signal to the integrated OADM circuit; combining the fourth optical signal and the eighth optical signal and outputting the combined signal to the third terminal station; Optical branching and coupling method.

10. using a first OADM circuit included in the integrated OADM circuit, generating the third optical signal and the fourth optical signal from the first optical signal input from a first terminal and the second optical signal input from the optical input / output circuit connected to a second terminal, outputting the third optical signal from a third terminal, and outputting the fourth optical signal from a fourth terminal to the optical input / output circuit; using a second OADM circuit included in the integrated OADM circuit, generating the seventh optical signal and the eighth optical signal from the fifth optical signal input from a fifth terminal and the sixth optical signal input from the optical input / output circuit connected to a sixth terminal, outputting the seventh optical signal from a seventh terminal, and outputting the eighth optical signal to the optical input / output circuit; 10. The optical branching and coupling method according to claim 9.

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