Optical Transmission System

Abstract

Provided is an optical switch device that can achieve switching of optical paths between each device that is connected to a optical fiber cable and each optical fiber pair that is included in the optical fiber cable. An optical switch device (3) comprises: a first optical switch means (31) that is provided with a plurality of input terminals (P_IN), and outputs an optical signal which was inputted to an input terminal (P_IN) selected from among the plurality of input terminals (P_IN); a second optical switch means (32) that is provided with a plurality of output terminals (P_OUT), and outputs, from an output terminal (P_OUT) selected from among the plurality of output terminals (P_OUT), the optical signal which was outputted by the first optical switch means (31); and a control means (22) that, on the basis of prescribed a first instruction, provides control to select an input terminal (P_IN) of the first switch means (31) and control to select an output terminal (P_OUT) of the second optical switch means (32).

Description

[Technical Field]

[0001] The present disclosure relates to an optical switch device and the like. [Background technology]

[0002] Systems that transmit optical signals using optical fiber cables (hereinafter referred to as "optical transmission systems") are known. Specifically, for example, optical transmission systems that transmit optical signals for communication between land stations using optical fiber cables laid on the ocean floor (so-called "submarine cables") are known. Patent Documents 1 to 3 disclose technologies related to optical transmission systems. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2002-280978 [Patent Document 2] Japanese Patent Application Laid-Open No. 2005-318567 [Patent Document 3] Japanese Patent Publication No. 2020-036312 Summary of the Invention [Problem to be solved by the invention]

[0004] Generally, multiple types of devices that input control signals to the optical fiber cable can be connected to the optical fiber cable in an optical transmission system. Specifically, for example, a test device that performs an optical pulse test to detect breaks in the optical fiber cable is connected to the optical fiber cable, and a control device that executes command control for remote devices is also connected to the optical fiber cable. An example of a test device that performs an optical pulse test is an OTDR (Optical Time Domain Reflectometer). Hereinafter, the optical pulse test performed by an OTDR may be referred to as an "OTDR test."

[0005] Generally, the optical fiber cable of an optical transmission system includes multiple optical fiber pairs, and bidirectional communication is achieved by using each optical fiber pair.

[0006] Here, it is preferable that the optical test signal output by the above-mentioned test device is selectively input to each of the multiple optical fiber pairs connected to the test device. Also, it is preferable that the optical control signal output by the above-mentioned control device is selectively input to each of the multiple optical fiber pairs that are the targets of optical pulse testing and command control transmission. From the viewpoint of realizing such selection, it is required to realize switching of the optical paths between each device connected to the optical fiber cable and each optical fiber pair included in the optical fiber cable in accordance with the test or control to be performed.

[0007] In view of the above-mentioned problems, the object of the present disclosure is to provide an optical switch device or the like that can realize switching of optical paths between, for example, individual devices connected to an optical fiber cable and individual optical fiber pairs included in the optical fiber cable. [Means for solving the problem]

[0008] An optical switch device according to one aspect of the present disclosure comprises a first optical switch means having a plurality of input terminals and outputting an optical signal input to a selected one of the plurality of input terminals, a second optical switch means having a plurality of output terminals and outputting an optical signal output by the first optical switch means from a selected one of the plurality of output terminals, and a control means that executes control to select an input terminal in the first optical switch means and control to select an output terminal in the second optical switch means based on a predetermined first instruction. [Effects of the Invention]

[0009] According to the present disclosure, for example, it is possible to realize switching of optical paths between individual devices connected to an optical fiber cable and individual optical fiber pairs included in the optical fiber cable. [Brief explanation of the drawings]

[0010] [Figure 1] FIG. 1 is a block diagram showing a portion of the optical transmission system according to the first embodiment, including an optical communication device and a first optical branching device. [Figure 2] FIG. 2 is a block diagram showing an optical communication device in the optical transmission system according to the first embodiment. [Figure 3] FIG. 3 is a block diagram showing parts of the optical transmission system according to the first embodiment, including an optical switch device, a server device, a test device, and a control device. [Figure 4] FIG. 4 is a block diagram showing an optical switch means of the optical switch device in the optical transmission system according to the first embodiment. [Figure 5] FIG. 5 is a flowchart showing the operation of the control means of the optical switch device in the optical transmission system according to the first embodiment. [Figure 6] FIG. 6 is a block diagram showing a portion including an optical communication device and a second optical branching device in an optical transmission system according to the second embodiment. [Figure 7] FIG. 7 is a block diagram showing a part of the optical transmission system according to the second embodiment, including an optical switch device, a server device, and a measurement device. [Figure 8] FIG. 8 is a block diagram showing an optical switch means of an optical switch device in an optical transmission system according to the second embodiment. [Figure 9] FIG. 9 is a flowchart showing the operation of the control means of the optical switch device in the optical transmission system according to the second embodiment. [Figure 10] FIG. 10 is a block diagram showing an optical switching device according to the third embodiment. [Figure 11] FIG. 11 is a block diagram showing an optical transmission system according to the third embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0011] Hereinafter, embodiments of the present disclosure will be described in detail with reference to the accompanying drawings.

[0012] [First embodiment] FIG. 1 is a block diagram showing a portion including an optical communication device and a first optical branching device in an optical transmission system according to a first embodiment. FIG. 2 is a block diagram showing an optical communication device in the optical transmission system according to the first embodiment. FIG. 3 is a block diagram showing a portion including an optical switching device, a server device, a test device, and a control device in the optical transmission system according to the first embodiment. FIG. 4 is a block diagram showing an optical switching means of an optical switching device in the optical transmission system according to the first embodiment. The optical transmission system according to the first embodiment will be described with reference to FIGS. 1 to 4.

[0013] 1, the optical transmission system 100 includes an optical communication device 1 and a first optical branching device 2. Furthermore, as shown in FIG. 3, the optical transmission system 100 includes an optical switch device 3, a server device 4, a test device 5, and a control device 6.

[0014] A plurality of optical communication devices, including the optical communication device 1, are provided along an optical fiber cable (not shown) including N optical fiber pairs FP_1 to FP_N. Here, N is any integer equal to or greater than 2. The optical fiber cable including the optical fiber pairs FP_1 to FP_N is laid, for example, on the seabed. That is, the optical fiber cable including the optical fiber pairs FP_1 to FP_N is, for example, a submarine cable. In this case, the optical transmission system 100 transmits an optical signal for communication between a first land station (not shown) and a second land station (not shown) using the submarine cable. More specifically, bidirectional communication between the first land station and the second land station is realized using each of the optical fiber pairs FP_1 to FP_N. Hereinafter, the optical signal for communication may be referred to as "communication light."

[0015] Here, a plurality of optical communication devices including the optical communication device 1 are provided, for example, at predetermined distance intervals along a submarine cable. This allows long-distance communication using the submarine cable to be realized. That is, each of the plurality of optical communication devices is configured, for example, by an optical repeater (more specifically, an optical submarine repeater). In other words, the optical communication device 1 is configured, for example, by an optical repeater (more specifically, an optical submarine repeater).

[0016] 2, each of the optical fiber pairs FP_1 to FP_N includes an optical fiber F_TX for transmission as seen from the first land station (F_TX_1 to F_TX_N in the figure). Also, each of the optical fiber pairs FP_1 to FP_N includes an optical fiber F_RX for reception as seen from the first land station (F_RX_1 to F_RX_N in the figure). The optical communication device 1 includes N optical communication means 11_1 to 11_N corresponding respectively to the N optical fiber pairs FP_1 to FP_N. Each of the optical communication means 11_1 to 11_N is formed by, for example, an optical repeater.

[0017] That is, each of the optical communication means 11_1 to 11_N includes a first amplifier (not shown). Here, the first amplifier is provided to amplify an optical signal transmitted through a corresponding one of the N optical fibers F_TX_1 to F_TX_N. In other words, the first amplifier is an amplifier for amplifying communication light transmitted from a first land station to a second land station. Also, each of the optical communication means 11_1 to 11_N includes a second amplifier (not shown) for amplifying an optical signal transmitted through a corresponding one of the N optical fibers F_RX_1 to F_RX_N. The second amplifier is provided to amplify an optical signal transmitted through a corresponding one of the N optical fibers F_RX_1 to F_RX_N. In other words, the second amplifier is an amplifier for amplifying communication light transmitted from the second land station to the first land station.

[0018] Here, in each of the optical communication means 11_1 to 11_N, the parameters (e.g., amplification factor) of each of the first amplifier and second amplifier are set by command control. In other words, the operation of each of the optical communication means 11_1 to 11_N is controlled by command control. The command control is executed by a control device 6, which will be described later.

[0019] Each of the optical communication means 11_1 to 11_N may include a loopback circuit (not shown) for implementing an OTDR test on a corresponding one of the N optical fiber pairs FP_1 to FP_N. The OTDR test on each of the optical fiber pairs FP_1 to FP_N is performed by a test device 5, which will be described later.

[0020] As shown in Fig. 1, a first optical branching device 2 is provided in the middle of an optical fiber cable (e.g., a submarine cable) including optical fiber pairs FP_1 to FP_N. The first optical branching device 2 is configured, for example, by an optical submarine branching device. The first optical branching device 2 branches each of the optical fiber pairs FP_1 to FP_N. The branched branches are connected to a test device 5 and a control device 6, respectively, via an optical switch device 3. In other words, the test device 5 and the control device 6 are connected to each of the optical fiber pairs FP_1 to FP_N, respectively, via the optical switch device 3.

[0021] The first optical branching device 2 may include the same amplifiers (i.e., a first amplifier and a second amplifier) ​​as the optical communication device 1. The first optical branching device 2 may also include the same loopback circuit (i.e., a loopback circuit for OTDR testing) as the optical communication device 1. The first optical branching device 2 may also be configured integrally with the optical communication device 1.

[0022] As shown in Fig. 3, the optical switch device 3 includes an optical switch means 21 and a control means 22. As shown in Fig. 4, the optical switch means 21 includes a first optical switch means 31, a second optical switch means 32, and a third optical switch means 33. Each of the first optical switch means 31, the second optical switch means 32, and the third optical switch means 33 is composed of at least one optical switch SW. In other words, the optical switch means 21 is composed of a plurality of optical switches SW.

[0023] Specifically, for example, the first optical switch means 31 is configured with a two-input, one-output (hereinafter sometimes referred to as "2×1") optical switch SW_1. The second optical switch means 32 is configured with a one-input, N-output (hereinafter sometimes referred to as "1×N") optical switch SW_2. The output terminal of the optical switch SW_1 is connected to the input terminal of the optical switch SW_2. In other words, the optical switches SW_1 and SW_2 are arranged in series with each other.

[0024] The third optical switch means 33 is composed of an N-input, 1-output (hereinafter sometimes referred to as "N×1") optical switch SW_3 and a 1-input, 2-output (hereinafter sometimes referred to as "1×2") optical switch SW_4. The output terminal of the optical switch SW_3 is connected to the input terminal of the optical switch SW_4. That is, the optical switches SW_3 and SW_4 are arranged in series with each other.

[0025] The first optical switch means 31 has a plurality of input terminals P_IN. More specifically, the first optical switch means 31 has two input terminals P_IN_1 and P_IN_2. The input terminal P_IN_1 is connected to an output optical fiber F_OUT_1 in the test device 5. The input terminal P_IN_2 is connected to an output optical fiber F_OUT_2 in the control device 6.

[0026] The second optical switch means 32 has a plurality of output terminals P_OUT. More specifically, the second optical switch means 32 has N output terminals P_OUT_1 to P_OUT_N. The N output terminals P_OUT_1 to P_OUT_N are respectively connected to N optical fibers F_TX_1 to F_TX_N.

[0027] The third optical switch means 33 has a plurality of input terminals. More specifically, the third optical switch means 33 has N input terminals. The N input terminals are respectively connected to N optical fibers F_RX_1 to F_RX_N. The third optical switch means 33 also has a plurality of output terminals. More specifically, the third optical switch means 33 has two output terminals. One of the two output terminals (hereinafter sometimes referred to as the "first output terminal") is connected to an input optical fiber F_IN_1 in the test equipment 5. The other of the two output terminals (hereinafter sometimes referred to as the "second output terminal") is connected to an input optical fiber F_IN_2 in the control device 6.

[0028] The control means 22 is configured by, for example, a computer. The control means 22 executes control to select an input terminal P_IN of the first optical switch means 31, and also executes control to select an output terminal P_OUT of the second optical switch means 32. Hereinafter, these controls may be collectively referred to as "first selection control." Furthermore, the control means 22 executes control to switch the optical paths in the first optical switch means 31 and the second optical switch means 32 so as to realize a state in which an optical signal input to the selected input terminal P_IN is output from the selected output terminal P_OUT. More specifically, the control means 22 executes control to switch the optical path in the optical switch SW_1 and the optical path in the optical switch SW_2. Hereinafter, such control may be referred to as "first switching control."

[0029] Furthermore, the control means 22 executes control to select an input terminal in the third optical switch means 33, and also executes control to select an output terminal in the third optical switch means 33. Hereinafter, these controls may be collectively referred to as "second selection control." Furthermore, the control means 22 executes control to switch the optical path in the third optical switch means 33 so as to realize a state in which an optical signal input to the selected input terminal is output from the selected output terminal. More specifically, the control means 22 executes control to switch the optical path in the optical switch SW_3 and the optical path in the optical switch SW_4. Hereinafter, such control may be referred to as "second switching control."

[0030] Here, the optical switching device 3 can freely communicate with the server device 4 via the network NW. The server device 4 is configured by, for example, a computer. The first selection control and the second selection control are executed based on instructions given by the server device 4.

[0031] That is, the server device 4 acquires information indicating the schedule of an OTDR test to be executed by the test device 5, which will be described later. Hereinafter, the information indicating the schedule of the OTDR test may be referred to as "first schedule information." The first schedule information may be input in advance by a person (such as an administrator of the optical transmission system 100). Alternatively, for example, the server device 4 receives the first schedule information from the test device 5 by communicating with the test device 5 via the network NW. Note that in FIG. 3, the connection line between the network NW and the test device 5 is omitted from the illustration.

[0032] The server device 4 uses the acquired first schedule information to determine a time period ΔT1 during which the OTDR test is performed by the test device 5 (hereinafter, sometimes referred to as a "test period"). The server device 4 also uses the acquired first schedule information to determine timings T1 during which the OTDR test is performed on each optical fiber pair FP within the test period ΔT1 (hereinafter, sometimes referred to as a "test timing"). Specifically, for example, the server device 4 determines N test timings T1_1 to T1_N corresponding respectively to the N optical fiber pairs FP_1 to FP_N in each test period ΔT1.

[0033] The server device 4 also acquires information (hereinafter sometimes referred to as "second schedule information") indicating a schedule for command control executed by the control device 6, which will be described later. The second schedule information is, for example, information that has been input in advance by a person (such as an administrator of the optical transmission system 100). Alternatively, for example, the server device 4 receives the first schedule information from the control device 6 by communicating with the control device 6 via the network NW. Note that in FIG. 3, the connection line between the network NW and the control device 6 is omitted from the illustration.

[0034] The server device 4 uses the acquired second schedule information to determine a time period (hereinafter sometimes referred to as a "control period") ΔT2 during which command control is executed by the control device 6. The server device 4 also uses the acquired second schedule information to determine timings (hereinafter sometimes referred to as "control timings") T2 during which command control is executed for each of the optical communication means 11 within the control period ΔT2. Specifically, for example, the server device 4 determines N control timings T2_1 to T2_N corresponding respectively to the N optical communication means 11_1 to 11_N during each of the control periods ΔT2.

[0035] The control period ΔT2 is usually set to a time interval different from that of the test period ΔT1. In other words, the control period ΔT2 is set to a time interval that avoids the test period ΔT1. This makes it possible to prevent each control timing T2 from overlapping with each test timing T1.

[0036] Based on the results of these determinations, the server device 4 generates a signal instructing a selection in the first selection control. Hereinafter, the signal instructing a selection in the first selection control may be referred to as the "first instruction signal." Also, based on the results of these determinations, the server device 4 generates a signal instructing a selection in the second selection control. Hereinafter, the signal instructing a selection in the second selection control may be referred to as the "second instruction signal."

[0037] That is, the first instruction signal includes an instruction to select one input terminal P_IN_1 of two input terminals P_IN_1, P_IN_2 included in the first optical switch means 31 during each test period ΔT1. The first instruction signal also includes an instruction to select one corresponding output terminal P_OUT of N output terminals P_OUT_1 to P_OUT_N included in the second optical switch means 32 during each of N test timings T1_1 to T1 to N.

[0038] The first instruction signal also includes an instruction to select one input terminal P_IN_2 of two input terminals P_IN_1, P_IN_2 included in the first optical switch means 31 during each control period ΔT2. The first instruction signal also includes an instruction to select one corresponding output terminal P_OUT of N output terminals P_OUT_1 to P_OUT_N included in the second optical switch means 32 during each of N control timings T2_1 to T2 to N.

[0039] The second instruction signal also includes an instruction to select, in each test period ΔT1, a first output terminal of the two output terminals of the third optical switch means 33. The second instruction signal also includes an instruction to select, in each of the N test timings T1_1 to T1 to N, a corresponding one input terminal of the N input terminals of the third optical switch means 33.

[0040] The second instruction signal also includes an instruction to select, in each control period ΔT2, a second output terminal of the two output terminals of the third optical switch means 33. The second instruction signal also includes an instruction to select, in each of the N control timings T2_1 to T2_N, a corresponding one input terminal of the N input terminals of the third optical switch means 33.

[0041] The server device 4 transmits the generated first instruction signal and second instruction signal to the optical switch device 3. The optical switch device 3 receives the transmitted first instruction signal and second instruction signal. The control means 22 executes first selection control based on the instruction indicated by the received first instruction signal. Also, the control means 22 executes second selection control based on the instruction indicated by the received second instruction signal.

[0042] Hereinafter, the instructions indicated by the first instruction signal may be collectively referred to as "first instructions." Also, the instructions indicated by the second instruction signal may be collectively referred to as "second instructions." As described above, the content of the second instructions at each test timing T1 corresponds to the content of the first instructions at each test timing T1. Also, the content of the second instructions at each control timing T2 corresponds to the content of the first instructions at each control timing T2.

[0043] That is, at each of the N test timings T1_1 to T1_N, the optical paths in the first optical switch means 31 and the second optical switch means 32 are set to an optical path connecting the optical fiber F_IN_1 to a corresponding one of the N optical fibers F_TX_1 to F_TX_N. This is based on the first instruction. Also, at each of the N test timings T1_1 to T1_N, the optical path in the third optical switch means 33 is set to an optical path connecting the optical fiber F_RX to a corresponding one of the N optical fibers F_RX_1 to F_RX_N. This is based on the second instruction.

[0044] Similarly, at each of the N control timings T2_1 to T2_N, the optical paths in the first optical switch means 31 and the second optical switch means 32 are set to an optical path connecting the optical fiber F_IN_2 to a corresponding one of the N optical fibers F_TX_1 to F_TX_N. This is based on a first instruction. Also, at each of the N control timings T2_1 to T2_N, the optical path in the third optical switch means 33 is set to an optical path connecting the optical fiber F_RX to a corresponding one of the N optical fibers F_RX_1 to F_RX_N. This is based on a second instruction.

[0045] In this way, since the content of the second instruction corresponds to the content of the first instruction, at each timing (T1, T2) when the OTDR test or command control is executed, the optical path in the third optical switch means 33 becomes the optical path corresponding to the optical paths in the first optical switch means 31 and the second optical switch means 32. As a result, as will be described later, an OTDR test is realized in each of the optical fiber pairs FP_1 to FP_N. Also, as will be described later, a response to command control for each of the optical communication means 11_1 to 11_N is realized.

[0046] The test equipment 5 is configured by, for example, an optical time domain reflectometer (i.e., OTDAR). The test equipment 5 is connected to the optical switch device 3 using an output optical fiber F_OUT_1 and an input optical fiber F_IN_1. As described above, the optical fiber F_OUT_1 is connected to the input terminal P_IN_1 of the first optical switch means 31. Furthermore, the optical fiber F_IN_1 is connected to the first output terminal of the third optical switch means 33. The test equipment 5 performs an OTDR test on each of the optical fiber pairs FP_1 to FP_N.

[0047] That is, the test device 5 outputs an optical signal for OTDR testing at a predetermined timing based on a predetermined schedule. Hereinafter, the optical signal for OTDR testing may be referred to as an "optical signal for testing" or "test light." Specifically, for example, the test device 5 outputs test light at each of N test timings T1_1 to T1_N. The output test light passes through the optical fiber F_OUT_1 and is input to the optical switch means 21 of the optical switch device 3. More specifically, the output test light is input to the input terminal P_IN_1 of the first optical switch means 31.

[0048] At this time, the optical paths in the first optical switch means 31 and the second optical switch means 32 are switched by the control means 22 as described above. Therefore, at each of the N test timings T1_1 to T1_N, the input test light is output from a corresponding one of the N output terminals P_OUT_1 to P_OUT_N provided in the second optical switch means 32. That is, at each of the N test timings T1_1 to T1_N, the input test light is output to a corresponding one of the N optical fibers F_TX_1 to F_TX_N.

[0049] Here, in the middle of an optical fiber cable (e.g., a submarine cable) including the optical fiber pairs FP_1 to FP_N, a loopback circuit for OTDR testing is provided at one or more predetermined positions in each of the optical fiber pairs FP_1 to FP_N. Specifically, for example, in each of a plurality of optical communication devices including the optical communication device 1, N loopback circuits respectively corresponding to the N optical fiber pairs FP_1 to FP_N are provided. Alternatively, for example, N loopback circuits respectively corresponding to the N optical fiber pairs FP_1 to FP_N are provided between every two adjacent optical communication devices among a plurality of optical communication devices including the optical communication device 1.

[0050] By providing such a loopback circuit, the test light transmitted through each of the N optical fibers F_TX_1 to F_TX_N then transmits through a corresponding one of the N optical fibers F_RX_1 to F_RX_N, and returns to the optical switch means 21 of the optical switch device 3. More specifically, at each of the N test timings T1_1 to T1_N, the transmitted test light is input to a corresponding one of the N input terminals of the third optical switch means 33. Hereinafter, the test light returning to the optical switch means 21 may be referred to as "return light."

[0051] At this time, the optical path in the third optical switch means 33 is switched by the control means 22 as described above. Therefore, at each of the N test timings T1_1 to T1_N, the input return light is output from the first output terminal of the two output terminals of the third optical switch means 33. That is, at each of the N test timings T1_1 to T1_N, the input return light is output to the optical fiber F_IN_1.

[0052] The output return light passes through the optical fiber F_IN_1 and is input to the test equipment 5. The test equipment 5 uses the input return light to perform signal processing for an OTDR test. Note that various known techniques can be used for signal processing for an OTDR test. Detailed descriptions of these techniques will be omitted.

[0053] In this way, an OTDR is realized for each of the optical fiber pairs FP_1 to FP_N. The results of such OTDR testing are used, for example, to monitor the state of each of the optical fiber pairs FP_1 to FP_N. More specifically, the results of such OTDR testing are used to detect whether or not a break has occurred in each of the optical fiber pairs FP_1 to FP_N, and to detect the position where the break has occurred.

[0054] The control device 6 is configured by, for example, a computer equipped with an optical transceiver. The control device 6 is connected to the optical switch device 3 using the output optical fiber F_OUT_2 and the input optical fiber F_IN_2. As described above, the optical fiber F_OUT_2 is connected to the input terminal P_IN_2 of the first optical switch means 31. Furthermore, the optical fiber F_IN_2 is connected to the second output terminal of the third optical switch means 33. The control device 6 executes command control for each of the optical communication means 11_1 to 11_N.

[0055] That is, the control device 6 generates commands for controlling the operation of each of the optical communication means 11_1 to 11_N. Specifically, for example, the control device 6 generates commands for setting parameters (such as amplification factor) of individual amplifiers in each of the optical communication means 11_1 to 11_N. The control device 6 outputs an optical signal (hereinafter, sometimes referred to as a "control optical signal" or "control light") indicating the generated command at a predetermined timing based on a predetermined schedule.

[0056] Specifically, for example, the control device 6 outputs control light for a corresponding one of the N optical communication means 11_1 to 11_N at each of N control timings T2_1 to T2_N. The output control light passes through the optical fiber F_OUT_2 and is input to the optical switch means 21 of the optical switch device 3. More specifically, the output control light is input to the input terminal P_IN_2 of the first optical switch means 31.

[0057] At this time, the optical paths in the first optical switch means 31 and the second optical switch means 32 are switched by the control means 22 as described above. Therefore, at each of the N control timings T2_1 to T2_N, the input control light is output from a corresponding one of the N output terminals P_OUT_1 to P_OUT_N provided in the second optical switch means 32. That is, at each of the N test timings T1_1 to T1_N, the input test light is output to a corresponding one of the N optical fibers F_TX_1 to F_TX_N.

[0058] As a result, control light corresponding to each of the optical communication means 11_1 to 11_N is transmitted. Each of the optical communication means 11_1 to 11_N controls its own operation based on a command indicated by the control light. Specifically, for example, each of the optical communication means 11_1 to 11_N sets parameters (such as amplification factor) of each amplifier based on the command indicated by the control light. At this time, each of the optical communication means 11_1 to 11_N outputs an optical signal (hereinafter sometimes referred to as "response light") for responding to the control light. The response light is, for example, an optical signal indicating a positive response (so-called "ACK") or a negative response (so-called "NACK").

[0059] That is, at each of the N control timings T2_1 to T2_N, a corresponding one of the N optical communication means 11_1 to 11_N outputs a response light to a corresponding one of the N optical fibers F_RX_1 to F_RX_N. The output response light is transmitted through the corresponding one optical fiber F_RX and input to the optical switch means 21. More specifically, the output response light is input to a corresponding one of the N input terminals of the third optical switch means 33.

[0060] At this time, the optical path in the third optical switch means 33 is switched by the control means 22 as described above. Therefore, at each of the N control timings T2_1 to T2_N, the input response light is output from the second output terminal of the two output terminals of the third optical switch means 33. That is, at each of the N control timings T2_1 to T2_N, the input response light is output to the optical fiber F_IN_2.

[0061] As a result, the control device 6 acquires a response light at each of the N control timings T2_1 to T2_N. This response light is output by a corresponding one of the N optical communication means 11_1 to 11_N. In other words, the control device 6 acquires a response light output by one optical communication means 11 that is the destination of the control light (i.e., the target of command control) at each of the N control timings T2_1 to T2_N. As a result, the control device 6 can know the result of the command control.

[0062] In this way, command control for each of the optical communication means 11_1 to 11_N is realized. Note that the content of command control for each of the optical communication means 11_1 to 11_N is not limited to the above specific example (i.e., setting of the amplification factor). Various known techniques can be used for command control. Detailed explanation of these techniques will be omitted.

[0063] In this manner, the main part of the optical transmission system 100 is configured.

[0064] The optical transmission system 100 includes a portion installed on land. Here, the portion installed on land is, for example, a portion including a first land station, a portion including a second land station, or a portion including an optical switch device 3, a test device 5, and a control device 6. The optical transmission system 100 also includes a portion installed on the seabed (for example, a portion including a submarine cable). A predetermined interface is used to connect the portion installed on land and the portion installed on the seabed. Specifically, for example, an OCI (Open Cable Interface) is used. FI_1 to FI_N in FIG. 3 indicate such interfaces.

[0065] Next, a description will be given of the operation of the optical switching device 3 in the optical transmission system 100. More specifically, the operation of the control means 22 will be mainly described with reference to the flowchart shown in FIG.

[0066] First, the optical switching device 3 receives an instruction signal transmitted by the server device 4. As a result, the control means 22 acquires instructions contained in the received instruction signal. More specifically, the control means 22 acquires a first instruction and a second instruction (step ST1).

[0067] Next, the control means 22 executes first selection control and first switching control based on the first instruction acquired in step ST1 (step ST2). That is, based on the acquired first instruction, the control means 22 executes control to select the input terminal P_IN of the first optical switch means 31 and executes control to select the output terminal P_OUT of the second optical switch means 32. Furthermore, the control means 22 executes control to switch the optical paths of the first optical switch means 31 and the second optical switch means 32 so as to realize a state in which the optical signal input to the selected input terminal P_IN is output from the selected output terminal P_OUT.

[0068] Furthermore, the control means 22 executes second selection control and second switching control based on the second instruction acquired in step ST1 (step ST3). That is, based on the acquired second instruction, the control means 22 executes control to select an input terminal in the third optical switch means 33, and executes control to select an output terminal in the third optical switch means 33. Furthermore, the control means 22 executes control to switch the optical path in the third optical switch means 33 so as to realize a state in which an optical signal input to the selected input terminal is output from the selected output terminal.

[0069] Next, a modification of the optical transmission system 100 will be described.

[0070] First, the optical transmission system 100 may not include the first optical branching device 2. In this case, the optical switching device 3, the test device 5, and the control device 6 may be provided in, for example, the first land station or the second land station.

[0071] Second, the optical transmission system 100 may not include the server device 4. In this case, the control means 22 may use preset first and second instructions instead of the first and second instructions given by the server device 4.

[0072] For example, if the schedule of the OTDR test periodically executed by the test device 5 is fixed and the schedule of the command control periodically executed by the control device 6 is fixed, it is not necessary to change the first instruction and the second instruction. In this case, the control means 22 may execute the first selection control and the second selection control based on the first instruction and the second instruction that are preset based on these schedules.

[0073] That is, the first instruction may be any predetermined instruction, and the second instruction may be any instruction corresponding to the first instruction from the viewpoint of implementing an OTDR test and responding to command control.

[0074] Third, the devices connected to each of the optical fiber pairs FP_1 to FP_N via the optical switch device 3 are not limited to the test device 5 and the control device 6. The connected devices may be any devices that output any optical signal to each of the optical fiber pairs FP_1 to FP_N or that accept input of any optical signal from each of the optical fiber pairs FP_1 to FP_N. In the second embodiment described later, an example in which devices other than the test device 5 and the control device 6 are connected will be described. More specifically, an example in which a measurement device that performs optical spectrum measurement is connected will be described. Note that an OSA (Optical Spectrum Analyzer) is an example of a measurement device that performs optical spectrum measurement. Hereinafter, optical spectrum measurement performed by an OSA may be referred to as "OSA measurement."

[0075] Furthermore, depending on the type of device to be connected, the optical switch means 21 may not have the third optical switch means 33. In the second embodiment described later, an example in which the third optical switch means 33 is not provided will be described.

[0076] Fourth, the number of input terminals P_IN in the first optical switch means 31 is not limited to two. Likewise, the number of output terminals in the third optical switch means 33 is not limited to two. The number of these terminals may be two or more. For example, the number of these terminals may vary depending on the number or type of devices connected to the optical fiber cable including the optical fiber pairs FP_1 to FP_N.

[0077] Next, the effects of the optical switch device 3 will be described.

[0078] As described above, the first optical switch means 31 has a plurality of input terminals P_IN, and outputs an optical signal input to a selected one of the plurality of input terminals P_IN. The second optical switch means 32 has a plurality of output terminals P_OUT, and outputs an optical signal output by the first optical switch means 31 from a selected one of the plurality of output terminals P_OUT. The control means 22 executes control to select the input terminal P_IN in the first optical switch means 31 and control to select the output terminal P_OUT in the second optical switch means 32 based on a predetermined first instruction.

[0079] By using the optical switch device 3 equipped with these means (31, 32, 22), it is possible to switch the optical path between each device (5, 6) connected to the optical fiber cable and each optical fiber pair (FP_1 to FP_N) included in the optical fiber cable.

[0080] Here, as an optical switch device for comparison with the optical switch device 3, consider the following optical switch device. That is, in the optical switch device 3, the first optical switch means 31 and the second optical switch means 32 are separate from each other. Specifically, for example, as described above, the first optical switch means 31 is configured with a 2×1 optical switch SW_1, and the second optical switch means 32 is configured with a 1×N optical switch SW_2. In contrast, in the comparative optical switch device, the functions corresponding to the first optical switch means 31 and the second optical switch means 32 are realized by a single optical switch. More specifically, this function is realized by a 2-input N-output (hereinafter referred to as "2×N") optical switch.

[0081] By using the 2×1 optical switch SW_1 and the 1×N optical switch SW_2, it is possible to simplify the switching of the optical paths in each optical switch compared to when a 2×N optical switch is used. In other words, because the first optical switch means 31 and the second optical switch means 32 are separate components (for example, the optical switch SW_1 and the optical switch SW_2), it is possible to more easily realize the above-described switching of the optical paths compared to when the first optical switch means 31 and the second optical switch means 32 are a single component (for example, a 2×N optical switch).

[0082] Furthermore, the following optical transmission system is considered as a comparative optical transmission system to the optical transmission system 100 including the optical switching device 3. That is, the comparative optical transmission system does not have an optical switching device equivalent to the optical switching device 3. Instead, in the comparative optical transmission system, the test device 5 and the control device 6 are each provided with an N-output optical switch for output and an N-input optical switch for input. As a result, the test device 5 and the control device 6 are each connected to each of the N optical fibers F_TX_1 to F_TX_N and also to each of the N optical fibers F_RX_1 to F_RX_N without going through an optical switching device.

[0083] When the optical switching device 3 is connected to the interfaces FI_1 to FI_N (i.e., the optical transmission system 100), the connection is simpler than when the test device 5 and the control device 6 are connected to the interfaces FI_1 to FI_N (i.e., the comparative optical transmission system). In other words, by providing the optical switching device 3, it is possible to simplify the connection of devices to the interfaces FI_1 to FI_N. This makes it possible to easily accommodate, for example, a system configuration compatible with OCI (so-called "open cable").

[0084] Next, the effects of the optical transmission system 100 will be described.

[0085] The optical transmission system 100 includes an optical switch device 3. This provides the above-described effects. That is, it is possible to realize switching of optical paths between the individual devices (5, 6) connected to the optical fiber cable and the individual optical fiber pairs (FP_1 to FP_N) included in the optical fiber cable. In particular, it is possible to easily realize such switching of optical paths. Furthermore, the optical transmission system 100 can easily accommodate an open cable system configuration.

[0086] The optical transmission system 100 also includes a test device 5 connected to one of the multiple input terminals P_IN and outputting test light, which is an optical signal for optical pulse testing, to the optical switching device 3. The optical transmission system 100 also includes a control device 6 connected to another of the multiple input terminals P_IN and outputting control light, which is an optical signal for command control, to the optical switching device 3. This makes it possible to realize, for example, the optical transmission system 100 having the system configurations shown in Figures 1 and 3. Furthermore, for example, it is possible to realize both OTDR testing and command control.

[0087] The optical transmission system 100 also includes an optical communication device 1 including a plurality of optical communication means 11 connected to a plurality of output terminals P_OUT, respectively. Each of the plurality of optical communication means 11 is controlled by control light. This makes it possible to realize, for example, the optical transmission system 100 having the system configuration shown in Figures 1 and 2. Furthermore, for example, it is possible to realize command control for each of the optical communication means 11_1 to 11_N.

[0088] Furthermore, each of the plurality of optical communication means 11 is connected to the optical switch device 3 using an optical fiber pair FP, and outputs response light, which is an optical signal for responding to the control light, to the optical fiber pair FP. The optical switch device 3 includes a third optical switch means 33 for switching the optical path in the optical switch device 3 based on a second instruction corresponding to the first instruction so that the response light output by each of the plurality of optical communication means 11 is transmitted to the control device 6. This makes it possible to realize a response to command control.

[0089] The optical transmission system 100 also includes a server device 4 that issues a first instruction to the optical switching device 3. This allows different first instructions to be issued to the optical switching device 3 according to a schedule of, for example, an OTDR test or command control executed by each device (5, 6). As a result, the optical switching device 3 can dynamically switch the optical path according to the schedule.

[0090] The optical transmission system 100 also includes a server device 4 that provides a first instruction and a second instruction to the optical switch device 3. This allows the optical switch device 3 to be provided with a first instruction and a second instruction that correspond to each other.

[0091] [Second embodiment] FIG. 6 is a block diagram showing a portion of an optical transmission system according to a second embodiment, the portion including an optical communication device and a second optical branching device. FIG. 7 is a block diagram showing a portion of an optical transmission system according to the second embodiment, the portion including an optical switch device, a server device, and a measurement device. FIG. 8 is a block diagram showing an optical switch means of an optical switch device in the optical transmission system according to the second embodiment. The optical transmission system according to the second embodiment will be described with reference to FIGS. 6 to 8. In FIGS. 6 to 8, elements similar to those shown in FIGS. 1 to 4 are designated by the same reference numerals, and description thereof will be omitted.

[0092] 6, the optical transmission system 100a includes an optical communication device 1 and a second optical branching device 7. Furthermore, as shown in FIG.

[0093] As shown in Fig. 6, a second optical branching device 7 is provided in the middle of an optical fiber cable (e.g., a submarine cable) including optical fiber pairs FP_1 to FP_N. The second optical branching device 7 is configured, for example, by an optical submarine branching device. The second optical branching device 7 branches each of the optical fiber pairs FP_1 to FP_N. The branched branches are connected to a measuring device 8 via an optical switch device 3a. In other words, the measuring device 8 is connected to each of the optical fiber pairs FP_1 to FP_N via the optical switch device 3a.

[0094] As shown in Fig. 7, the optical switch device 3a includes an optical switch means 21a and a control means 22a. As shown in Fig. 8, the optical switch means 21a includes a first optical switch means 31a and a second optical switch means 32a. Each of the first optical switch means 31a and the second optical switch means 32a is composed of at least one optical switch SW. In other words, the optical switch means 21a is composed of a plurality of optical switches SW.

[0095] Specifically, for example, the first optical switch means 31a is composed of an N×1 optical switch SW_2 and an N×1 optical switch SW_3. The optical switches SW_2 and SW_3 are arranged in parallel to each other. The second optical switch means 32a is composed of a 2×1 optical switch SW_1 and a 2×1 optical switch SW_4. The optical switches SW_1 and SW_4 are arranged in parallel to each other.

[0096] The output terminal of optical switch SW_2 is connected to one of two input terminals of optical switch SW_1. Hereinafter, one of the two input terminals of optical switch SW_1 may be referred to as the "first input terminal." The output terminal of optical switch SW_4 is connected to the other of the two input terminals of optical switch SW_1. Hereinafter, the other of the two input terminals of optical switch SW_1 may be referred to as the "second input terminal."

[0097] The optical switch SW_2 has N input terminals P_IN_1 to P_IN_N. Furthermore, the optical switch SW_3 has N input terminals P_IN_N+1 to P_IN_2N. As a result, the first optical switch means 31a has 2N input terminals P_IN_1 to P_IN_2N. Of the 2N input terminals P_IN_1 to P_IN_2N, the N input terminals P_IN_1 to P_IN_N are respectively connected to N optical fibers F_TX_1 to F_TX_N. Furthermore, the other N input terminals P_IN_N+1 to P_IN_2N of the 2N input terminals P_IN_1 to P_IN_2N are respectively connected to N optical fibers F_RX_1 to F_RX_N.

[0098] The optical switch SW_1 has one output terminal P_OUT_1. Furthermore, the optical switch SW_4 has one output terminal P_OUT_2. As a result, the second optical switch means 32a has two output terminals P_OUT_1 and P_OUT_2. Of the two output terminals P_OUT_1 and P_OUT_2, the output terminal P_OUT_1 is connected to the input optical fiber F_IN_3 in the measuring device 8. The other output terminal P_OUT_2 of the two output terminals P_OUT_1 and P_OUT_2 is what is called "empty." In other words, the output terminal P_OUT_2 is unused or not in use.

[0099] The control means 22a is configured by, for example, a computer. The control means 22a executes control to select the input terminal P_IN of the first optical switch means 31a, and also executes control to select the output terminal P_OUT of the second optical switch means 32a. That is, the control means 22a executes first selection control.

[0100] Furthermore, the control means 22a executes control to switch the optical paths in the first optical switch means 31a and the second optical switch means 32a so that a state is realized in which an optical signal input to the selected input terminal P_IN is output from the selected output terminal P_OUT. More specifically, the control means 22 executes control to switch the optical path in the optical switch SW_2, the optical path in the optical switch SW_3, the optical path in the optical switch SW_1, the optical path in the optical switch SW_4, and the optical paths between the optical switches SW_2, SW_3 and the optical switches SW_1, SW_4. That is, the control means 22a executes first switching control.

[0101] Here, the optical switching device 3a can freely communicate with the server device 4 via the network NW. The first selection control is executed based on an instruction given by the server device 4.

[0102] That is, the server device 4 acquires information (hereinafter sometimes referred to as "third schedule information") indicating a schedule of OSA measurements to be performed by the measuring device 8 (described later). The third schedule information is, for example, information that has been input in advance by a person (such as an administrator of the optical transmission system 100a). Alternatively, for example, the server device 4 receives the third schedule information from the measuring device 8 by communicating with the measuring device 8 via the network NW. Note that in FIG. 7, the connection line between the network NW and the measuring device 8 is omitted from the illustration.

[0103] Using the acquired third schedule information, the server device 4 determines a time period ΔT3 during which OSA measurement is performed by the measurement device 8 (hereinafter, sometimes referred to as a "measurement period"). The server device 4 also uses the acquired third schedule information to determine a timing T3 during the measurement period ΔT3 during which OSA measurement is performed on each of the optical fibers F_TX and F_RX (hereinafter, sometimes referred to as a "measurement timing").

[0104] Specifically, for example, the server device 4 determines N measurement timings T3_1 to T3_N corresponding respectively to the N optical fibers F_TX_1 to F_TX_N during each measurement period ΔT3. Also, the server device 4 determines N measurement timings T3_N+1 to T3_2N corresponding respectively to the N optical fibers F_RX_1 to F_RX_N during each measurement period ΔT3. That is, the server device 4 determines 2N measurement timings T3_1 to T3_2N corresponding respectively to the 2N optical fibers F_TX_1 to F_TX_N, F_RX_1 to F_RX_N during each measurement period ΔT3.

[0105] Based on the results of these determinations, the server device 4 generates a signal instructing a selection in the first selection control, that is, the server device 4 generates a first instruction signal.

[0106] The first instruction signal includes an instruction to select one output terminal P_OUT_1 of two output terminals P_OUT_1, P_OUT_2 of the second optical switch means 32a during each measurement period ΔT3, and also includes an instruction to select one corresponding input terminal P_IN of 2N input terminals P_IN_1 to P_IN_2N of the first optical switch means 31a during each of 2N measurement timings T3_1 to T3_2N.

[0107] The server device 4 transmits the generated first instruction signal to the optical switch device 3a. The optical switch device 3a receives the transmitted first instruction signal. The control means 22a executes the first selection control based on the instruction indicated by the received first instruction signal. That is, the control means 22a executes the first selection control based on the first instruction.

[0108] The measurement device 8 is configured, for example, by an optical spectrum analyzer (i.e., OSA). The measurement device 8 is connected to the optical switching device 3 using the input optical fiber F_IN_3. As described above, the optical fiber F_IN_3 is connected to the input terminal P_IN_1 of the first optical switch means 31a. The measurement device 8 performs OSA measurement on each of the optical fibers F_TX_1 to F_TX_N. The measurement device 8 also performs OSA measurement on each of the optical fibers F_RX_1 to F_RX_N.

[0109] That is, the optical transmission system 100a includes a light source device (not shown) for OSA measurement. The light source device is provided, for example, in the first land station or the second land station. Alternatively, for example, the light source device is configured integrally with the measurement device 8. The light source device outputs an optical signal for OSA measurement (hereinafter sometimes referred to as "measurement optical signal" or "measurement light") at a predetermined timing based on a predetermined schedule.

[0110] Specifically, for example, the light source device outputs measurement light to a corresponding one of the N optical fibers F_TX_1 to F_TX_N at each of the N measurement timings T3_1 to T3_N. The output measurement light propagates through the corresponding one of the optical fibers F_TX. Furthermore, the light source device outputs measurement light to a corresponding one of the N optical fibers F_RX_1 to F_RX_N at each of the other N measurement timings T3_N+1 to T3_2N. The output measurement light propagates through the corresponding one of the optical fibers F_RX.

[0111] At this time, the optical paths in the first optical switch means 31a and the second optical switch means 32a are switched by the control means 22a as described above. Therefore, at each of the N measurement timings T3_1 to T3_N, the measurement light transmitted through the corresponding one optical fiber F_TX passes through the optical switches SW_2, SW_1 and the optical fiber F_IN_3 and is input to the measurement device 8. Also, at each of the other N measurement timings T3_N+1 to T3_2N, the measurement light transmitted through the corresponding one optical fiber F_RX passes through the optical switches SW_3, SW_1 and the optical fiber F_IN_3 and is input to the measurement device 8.

[0112] The measurement device 8 uses the input measurement light to perform signal processing for OSA measurement. Note that various known techniques can be used for signal processing for OSA measurement. Detailed descriptions of these techniques will be omitted.

[0113] In this way, OSA measurement is performed on each of the optical fibers F_TX_1 to F_TX_N and F_RX_1 to F_RX_N. The results of this OSA measurement are used, for example, to monitor the status of each of the optical fibers F_TX_1 to F_TX_N and F_RX_1 to F_RX_N. More specifically, the results of this OSA are used to detect whether or not a break has occurred in each of the optical fibers F_TX_1 to F_TX_N and F_RX_1 to F_RX_N, and to detect the location of the break.

[0114] In this manner, the main part of the optical transmission system 100a is configured.

[0115] The optical transmission system 100a includes a portion installed on land. Here, the portion installed on land is, for example, a portion including a first land station, a portion including a second land station, or a portion including the optical switching device 3a and the measuring device 8. The optical transmission system 100a also includes a portion installed on the seabed (for example, a portion including a submarine cable). A predetermined interface is used to connect the portion installed on land and the portion installed on the seabed. Specifically, for example, an OCI is used. FI_1 to FI_N in FIG. 7 indicate such interfaces.

[0116] Next, the operation of the optical switch device 3a in the optical transmission system 100a will be described. More specifically, the operation of the control means 22a will be mainly described with reference to the flowchart shown in FIG.

[0117] First, the optical switching device 3a receives an instruction signal transmitted by the server device 4. As a result, the control means 22a acquires an instruction included in the received instruction signal. More specifically, the control means 22a acquires a first instruction (step ST1a).

[0118] Next, the control means 22a executes first selection control and first switching control based on the first instruction acquired in step ST1a (step ST2a). That is, the control means 22a executes control to select the input terminal P_IN of the first optical switch means 31a and control to select the output terminal P_OUT of the second optical switch means 32a based on the acquired first instruction. Furthermore, the control means 22a executes control to switch the optical paths of the first optical switch means 31a and the second optical switch means 32a so as to realize a state in which the optical signal input to the selected input terminal P_IN is output from the selected output terminal P_OUT.

[0119] Next, a modification of the optical transmission system 100a will be described.

[0120] First, the optical transmission system 100a may not include the second optical branching device 7. In this case, the optical switching device 3a and the measuring device 8 may be provided in, for example, the first land station or the second land station.

[0121] Second, the optical transmission system 100a may not include the server device 4. In this case, the control means 22a may use a preset first instruction instead of the first instruction given by the server device 4.

[0122] For example, if the OSA measurement schedule periodically performed by the measurement device 8 is fixed, it is not necessary to change the first instruction. In this case, the control means 22a may execute the first selection control based on a first instruction that is preset based on the schedule. In other words, the first instruction may be a predetermined instruction.

[0123] Third, the optical transmission system 100a may include the first optical branching device 2, the optical switching device 3, the testing device 5, and the control device 6 similar to those of the optical transmission system 100. That is, the optical transmission system 100a may include the testing device 5 and the control device 6, and may also include a measuring device 8. Furthermore, the optical transmission system 100a may include an optical switching device 3 provided between the optical fiber pairs FP_1 to FP_N and the testing device 5 and the control device 6, and may also include an optical switching device 3a provided between the optical fiber pairs FP_1 to FP_N and the measuring device 8.

[0124] In this case, the second optical branching device 7 may be configured integrally with the first optical branching device 2. For example, the first optical branching device 2 and the second optical branching device 7 may be configured as a single optical submarine branching device.

[0125] Next, the effects of the optical switch device 3a will be described.

[0126] By using the optical switch device 3a, it is possible to obtain the same effects as when using the optical switch device 3. In other words, it is possible to obtain the same effects as those described in the first embodiment.

[0127] That is, the first optical switch means 31a has a plurality of input terminals P_IN and outputs an optical signal input to a selected one of the plurality of input terminals P_IN. The second optical switch means 32a has a plurality of output terminals P_OUT and outputs an optical signal output by the first optical switch means 31 from a selected one of the plurality of output terminals P_OUT. The control means 22a executes control to select the input terminal P_IN of the first optical switch means 31a and control to select the output terminal P_OUT of the second optical switch means 32a based on a predetermined first instruction.

[0128] By using the optical switch device 3a equipped with these means (31a, 32a, 22a), it is possible to switch the optical path between each device (8) connected to the optical fiber cable and each optical fiber pair (FP_1 to FP_N) included in the optical fiber cable.

[0129] Here, as a comparative optical switch device to the optical switch device 3a, the following optical switch device is considered. That is, in the optical switch device 3a, the first optical switch means 31a and the second optical switch means 32a are separate from each other. Specifically, for example, as described above, the first optical switch means 31a is composed of an N×1 optical switch SW_2 and an N×1 optical switch SW_3, and the second optical switch means 32a is composed of a 2×1 optical switch SW_1 and a 2×1 optical switch SW_4. In contrast, in the comparative optical switch device, the functions corresponding to the first optical switch means 31a and the second optical switch means 32a are realized by a single optical switch. More specifically, this function is realized by a 2N-input, 2-output (hereinafter sometimes referred to as "2N×2") optical switch.

[0130] By using the N×1 optical switch SW_2, the N×1 optical switch SW_3, the 2×1 optical switch SW_1, and the 2×1 optical switch SW_4, it is possible to simplify the switching of the optical paths in each optical switch compared to when a 2N×2 optical switch is used. In other words, because the first optical switch means 31a and the second optical switch means 32a are separate components (for example, the optical switches SW_2, SW_3 and the optical switches SW_1, SW_4), it is possible to more easily realize the switching of the optical paths as described above compared to when the first optical switch means 31a and the second optical switch means 32a are a single component (for example, a 2N×2 optical switch).

[0131] Furthermore, by using the optical switch devices 3, 3a, it is possible to realize the connection of the test device 5 and the control device 6 to the optical fiber pairs FP_1 to FP_N, and also to realize the connection of the measurement device 8 to the optical fiber pairs FP_1 to FP_N. In particular, these connections can be made easily. As a result, it is possible to easily accommodate an open cable system configuration.

[0132] Here, the optical switches SW_1 to SW_4 included in the optical switching means 21a are the same as the optical switches SW_1 to SW_4 included in the optical switching means 21. Therefore, the optical switches SW_1 to SW_4 can be shared between the optical switching device 3 for connecting the test device 5 and the control device 6 and the optical switching device 3a for connecting the measurement device 8. As a result, the design costs and manufacturing costs of the optical switching devices 3 and 3a can be reduced.

[0133] [Third embodiment] Fig. 10 is a block diagram showing an optical switching device according to a third embodiment. The optical switching device according to the third embodiment will be described with reference to Fig. 10. Fig. 11 is a block diagram showing an optical transmission system according to the third embodiment. The optical transmission system according to the third embodiment will be described with reference to Fig. 11. In Figs. 10 and 11, elements similar to those shown in Figs. 1 to 4 are designated by the same reference numerals, and description thereof will be omitted.

[0134] Here, the optical switching device 3 according to the first embodiment and the optical switching device 3a according to the second embodiment are each an example of the optical switching device 3b according to the third embodiment. Also, the optical transmission system 100 according to the first embodiment and the optical transmission system 100a according to the second embodiment are each an example of the optical transmission system 100b according to the third embodiment.

[0135] As shown in Fig. 10, the optical switch device 3b includes a first optical switch means 31, a second optical switch means 32, and a control means 22. As shown in Fig. 11, the optical transmission system 100b includes the optical switch device 3b. Even in these cases, the same effects as those described in the first embodiment can be obtained, as described below.

[0136] That is, the first optical switch means 31 has a plurality of input terminals P_IN, and outputs an optical signal input to a selected input terminal P_IN of the plurality of input terminals P_IN. The second optical switch means 32 has a plurality of output terminals P_OUT, and outputs an optical signal output by the first optical switch means 31 from a selected output terminal P_OUT of the plurality of output terminals P_OUT. The control means 22 executes control to select the input terminal P_IN of the first optical switch means 31 and control to select the output terminal P_OUT of the second optical switch means 32 based on a predetermined first instruction.

[0137] By using the optical switch device 3b equipped with these means (31, 32, 22), it is possible to switch the optical path between each device (5, 6, 8) connected to the optical fiber cable and each optical fiber pair (FP_1 to FP_N) included in the optical fiber cable.

[0138] The optical transmission system 100b also includes an optical switching device 3b, which provides the above-described effects. That is, it is possible to realize switching of optical paths between the individual devices (5, 6, 8) connected to the optical fiber cable and the individual optical fiber pairs (FP_1 to FP_N) included in the optical fiber cable.

[0139] The optical switch device 3b may include a third optical switch means 33 in addition to the first optical switch means 31, the second optical switch means 32, and the control means 22. The optical switch device 3b may also include a first optical switch means 31a, a second optical switch means 32a, and a control means 22a instead of the first optical switch means 31, the second optical switch means 32, and the control means 22.

[0140] The optical transmission system 100b may also include a test device 5 and a control device 6 in addition to the optical switching device 3b. The optical transmission system 100b may also include an optical communication device 1 in addition to the optical switching device 3b. The optical transmission system 100b may also include a measurement device 8 in addition to the optical switching device 3b. The optical transmission system 100b may also include a server device 4 in addition to the optical switching device 3b.

[0141] 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.

[0142] A part or all of the above-described embodiments can be described as, but not limited to, the following supplementary notes.

[0143] [Note] [Appendix 1] a first optical switch means having a plurality of input terminals and outputting an optical signal input to a selected input terminal of the plurality of input terminals; a second optical switch means having a plurality of output terminals and outputting the optical signal output by the first optical switch means from a selected output terminal of the plurality of output terminals; a control means for executing control to select an input terminal in the first optical switch means and control to select an output terminal in the second optical switch means based on a predetermined first instruction; An optical switch device comprising: [Appendix 2] An optical transmission system comprising the optical switch device according to claim 1. [Appendix 3] a test device connected to any one of the plurality of input terminals and configured to output test light, which is an optical signal for optical pulse testing, to the optical switch device; a control device connected to any other input terminal of the plurality of input terminals and configured to output a control light, which is an optical signal for command control, to the optical switch device; 3. The optical transmission system according to claim 2, comprising: [Appendix 4] an optical communication device including a plurality of optical communication means connected to the plurality of output terminals, Each of the plurality of optical communication means is controlled by the control light. 4. The optical transmission system according to claim 3, [Appendix 5] each of the plurality of optical communication means is connected to the optical switch device using an optical fiber pair, and outputs a response light, which is an optical signal for responding to the control light, to the optical fiber pair; The optical switch device includes a third optical switch means for switching an optical path in the optical switch device based on a second instruction corresponding to the first instruction so that the response light output from each of the plurality of optical communication means is transmitted to the control device. 5. The optical transmission system according to claim 4, [Appendix 6] The optical transmission system according to claim 2, further comprising a measurement device connected to one of the plurality of output terminals and configured to receive input of measurement light, which is an optical signal for measuring an optical spectrum. [Appendix 7] 7. The optical transmission system according to claim 2, further comprising a server device that provides the first instruction to the optical switch device. [Appendix 8] 6. The optical transmission system according to claim 5, further comprising a server device that provides the first instruction and the second instruction to the optical switch device. [Explanation of symbols]

[0144] 1 Optical communication equipment 2. First optical branching device 3, 3a, 3b Optical switch device 4. Server equipment 5 Test equipment 6. Control device 7 Second optical branching device 8. Measuring equipment 11 Optical communication means 21, 21a Optical switch means 22, 22a Control means 31, 31a First optical switch means 32, 32a Second optical switch means 33 third optical switch means 100, 100a, 100b Optical Transmission System

Claims

1. an optical switch comprising: first optical switch means having a plurality of input terminals and outputting an optical signal input to a selected one of the plurality of input terminals; second optical switch means having a plurality of output terminals and outputting an optical signal output by the first optical switch means from a selected one of the plurality of output terminals; and control means for executing control to select an input terminal in the first optical switch means and control to select an output terminal in the second optical switch means; a test device connected to any one of the plurality of input terminals and configured to output test light, which is an optical signal for optical pulse testing, to the optical switch during a first period; a control device connected to any other input terminal of the plurality of input terminals and configured to output control light, which is an optical signal for command control, to the optical switch during a second period different from the first period; An optical transmission system comprising:

2. an optical communication device including a plurality of optical communication means connected to the plurality of output terminals, Each of the plurality of optical communication means is controlled by the control light.

2. The optical transmission system according to claim 1.

3. The optical transmission system described in Claim 2, characterized in that the control means performs control to select an input terminal in the first optical switch means and control to select an output terminal in the second optical switch means based on a predetermined first instruction.

4. each of the plurality of optical communication means is connected to the optical switch using an optical fiber pair, and outputs a response light, which is an optical signal for responding to the control light, to the optical fiber pair; The optical switch includes a third optical switch means for switching an optical path in the optical switch based on a second instruction corresponding to the first instruction so that the response light output from each of the plurality of optical communication means is transmitted to the control device.

4. The optical transmission system according to claim 3.

5. 2. The optical transmission system according to claim 1, further comprising a measurement device connected to one of the plurality of output terminals and configured to receive an input of measurement light, which is an optical signal for measuring an optical spectrum.

6. 4. The optical transmission system according to claim 3, further comprising a server device that issues the first instruction to the optical switch.

7. 5. The optical transmission system according to claim 4, further comprising a server device that issues the first instruction and the second instruction to the optical switch.

8. The control means during the first period, a first input terminal is selected as an input terminal of the first optical switch means; During the second period, a second input terminal different from the first input terminal is selected as an input terminal of the first optical switch means.

8. The optical transmission system according to claim 1, wherein the optical transmission system is a transmission system for transmitting a signal to a plurality of optical fibers.

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