Optical communication device, optical communication system, and transmission method

Abstract

An optical communication device including: a first optical switch that is connected to multiple optical transmission lines and outputs an optical signal input from one of the optical transmission lines to another one of the optical transmission lines; a second optical switch that is connected to multiple optical transmission lines and outputs an optical signal input from one of the optical transmission lines to another one of the optical transmission lines; and a transfer unit that transfers an optical signal transmitted from a first device connected to the first optical switch to a specific second device connected to the second optical switch.　

Description

Technical Field

[0005]

[0001] The present invention relates to an optical communication device, an optical communication system, and a transfer method.

Background Art

[0002] Conventionally, an optical communication device that can relay an optical signal according to a destination while reducing delay has been proposed (see, for example, Patent Document 1). FIG. 12 is a diagram showing a configuration example of an optical communication system 100 including a conventional optical communication device. The optical communication system 100 includes an optical SW 110 that constitutes the optical communication device and a control unit 115. Subscriber devices 140-1 to 140-3 are connected to the optical SW 110.

[0003] The optical SW 110 is connected to a plurality of optical transmission paths and outputs an optical signal input from any one of the optical transmission paths to another optical transmission path. The optical SW 110 shown in FIG. 12 has first ports 111-1 to 111-6 and second ports 112-1 to 112-6. Each first port 111 is connected to any one of subscriber devices 140-1 to 140-3 via any one of optical transmission paths 135-1 to 135-3. Optical transmission paths 136-1 to 136-4 and a return transmission path 137 are connected to each second port 112.

[0004] The return transmission path 137 is an optical transmission path for inputting an optical signal output from a certain port to another port. For example, in the example shown in FIG. 12, the return transmission path 137 is connected to the second port 112-4 and the second port 112-5. Thereby, for example, an optical signal output from the second port 112-4 can be input to the second port 112-5.

[0005] The control unit 115 is connected to the second port 112-6 of the optical switch 110 via the optical transmission path 136-4. The control unit 115 comprises a wavelength management control unit 120 and an optical switch control unit 130. The wavelength management control unit 120 assigns wavelengths to the subscriber equipment 140. The optical switch control unit 130 switches the paths of the optical switch 110. In the example shown in Figure 12, the optical switch control unit 130 switches the paths of the optical switch 110 to connect the first port 111-2 to which subscriber equipment 140-1 is connected to the second port 112-2, the first port 111-4 to which subscriber equipment 140-2 is connected to the second port 112-4, and the first port 111-5 to which subscriber equipment 140-3 is connected to the second port 112-5.

[0006] As a result, the optical signal transmitted from subscriber device 140-1 is input to the first port 111-2 of optical switch 110 via optical transmission path 135-1, and output to optical transmission path 136-2 from the second port 112-2 of optical switch 110. Furthermore, the optical signal transmitted from subscriber device 140-2 is input to the first port 111-4 of optical switch 110 via optical transmission path 135-2, and output to loopback transmission path 137 from the second port 112-4 of optical switch 110. The optical signal output to loopback transmission path 137 is input to the second port 112-5 of optical switch 110, and output to optical transmission path 135-3 from the first port 111-5 of optical switch 110. The optical signal output to optical transmission path 135-3 is transmitted to subscriber device 140-3.

[0007] As described above, low-latency communication can be achieved by using a loopback transmission path 137 to a port different from the port to which the subscriber device 140 is connected (for example, the first port 111) (for example, the second port 112). [Prior art documents] [Patent Documents]

[0008] [Patent Document 1] International Publication No. 2021 / 131202 [Overview of the project] [Problems that the invention aims to solve]

[0009] In the optical communication system 100 shown in Figure 12, by using multiple optical switches 110-1 to 110-P (where P is an integer of 2 or more) in parallel at one location, the maximum number of users that can be transmitted for each path can be increased. Figure 13 is a diagram illustrating a configuration in which multiple optical switches 110 are arranged in parallel. In the example shown in Figure 13, optical switches 110-1 to 110-P are arranged in parallel, and a subscriber device 140 is connected to each optical switch 110.

[0010] In order to perform loopback communication between subscriber device 140-1 connected to optical switch 110-1 and subscriber device 140-2 connected to optical switch 110-2, it is necessary to connect the second port 112-1 of optical switch 110-1 and the second port 112-1 of optical switch 110-2 with a loopback transmission path 137. If there are P optical switches 110 and one optical switch 110 accommodates n (where n is an integer greater than or equal to 1) subscriber devices 140, in order for each subscriber device 140 to connect with any other subscriber device 140 at any time, it is necessary to connect loopback transmission paths 137 from one optical switch 110 using n × (p-1) ports.

[0011] Within the optical switch 110, n connections are required to communicate with any subscriber device 140, so a total of np ports are needed between switches and within switches. It is conceivable to reduce the number of loopback transmission lines 137 and physically change the wiring each time a connection request is received, but this is undesirable because it increases on-site work. Therefore, there is a need for a technology that eliminates the need for physical wiring and allows each subscriber device to connect with any other subscriber device at any time using fewer loopback transmission lines than before.

[0012] In view of the above circumstances, the present invention aims to provide a technology that enables each subscriber device to connect with any other subscriber device at any time when performing loopback communication in an optical communication system equipped with multiple optical switches, using fewer loopback transmission paths than in the conventional method. [Means for solving the problem]

[0013] One aspect of the present invention is an optical communication device comprising: a first optical switch connected to a plurality of optical transmission paths and outputting an optical signal input from one of the optical transmission paths to another optical transmission path; a second optical switch connected to a plurality of optical transmission paths and outputting an optical signal input from one of the optical transmission paths to another optical transmission path; and a transfer unit that transfers an optical signal transmitted from a first device connected to the first optical switch to a specific second device connected to the second optical switch.

[0014] One aspect of the present invention is an optical communication system comprising: a first optical switch connected to a plurality of optical transmission paths and outputting an optical signal input from one of the optical transmission paths to another optical transmission path; a second optical switch connected to a plurality of optical transmission paths and outputting an optical signal input from one of the optical transmission paths to another optical transmission path; and a transfer unit that transfers an optical signal transmitted from a first device connected to the first optical switch to a specific second device connected to the second optical switch.

[0015] One aspect of the present invention is a transfer method in which a first optical switch is connected to a plurality of optical transmission paths and outputs an optical signal input from one of the optical transmission paths to another optical transmission path, and a second optical switch is connected to a plurality of optical transmission paths and outputs an optical signal input from one of the optical transmission paths to another optical transmission path, and an optical signal transmitted from a first device connected to the first optical switch is transferred to a specific second device connected to the second optical switch. [Effects of the Invention]

[0016] According to the present invention, when performing folded-back communication in an optical communication system including a plurality of optical switches, each subscriber device can be connected to any subscriber device at an arbitrary timing using a smaller number of folded-back transmission paths than in the prior art.

Brief Description of the Drawings

[0017] [Figure 1] It is a configuration diagram of an optical communication system in the first embodiment. [Figure 2] It is a block diagram showing a specific example of the functional configuration (part 1) of the folded-back transfer unit in the first embodiment. [Figure 3] It is a sequence diagram for explaining the processing flow of the optical communication system in the first embodiment. [Figure 4] It is a block diagram showing a specific example of the functional configuration (part 2) of the folded-back transfer unit in the first embodiment. [Figure 5] It is a block diagram showing a specific example of the functional configuration (part 3) of the folded-back transfer unit in the first embodiment. [Figure 6] It is a block diagram showing a specific example of the functional configuration (part 1) of the folded-back transfer unit in the second embodiment. [Figure 7] It is a block diagram showing a specific example of the functional configuration (part 2) of the folded-back transfer unit in the second embodiment. [Figure 8] It is a block diagram showing a specific example of the functional configuration (part 3) of the folded-back transfer unit in the second embodiment. [Figure 9] It is a block diagram showing a specific example of the functional configuration (part 1) of the folded-back transfer unit in the third embodiment. [Figure 10] It is a block diagram showing a specific example of the functional configuration (part 2) of the folded-back transfer unit in the third embodiment. [Figure 11] It is a block diagram showing a specific example of the functional configuration (part 3) of the folded-back transfer unit in the third embodiment. [Figure 12] It is a diagram showing a configuration example of an optical communication system including a conventional optical communication device. [Figure 13]This is a diagram for explaining a configuration in which a plurality of optical SWs are arranged in parallel.

Embodiments for Carrying out the Invention

[0018] Hereinafter, an embodiment of the present invention will be described with reference to the drawings. (First Embodiment) FIG. 1 is a configuration diagram of an optical communication system 1 in the first embodiment. The optical communication system 1 includes P optical SWs 10-1 to 10-P (P is an integer of 2 or more), P optical SWs 11-1 to 11-P, a control unit 12, and a folding transfer unit 14. In the following description, it is assumed that the optical SWs 10-1 to 10-P are used for transmitting optical signals in the upstream direction, and the optical SWs 11-1 to 11-P are used for transmitting optical signals in the downstream direction. In the following description, when the optical SWs 10-1 to 10-P are not distinguished, they are simply referred to as optical SW10, and when the optical SWs 11-1 to  11-P are not distinguished, they are simply referred to as optical SW11. Note that the optical SW10, optical SW11, control unit 12, and folding transfer unit 14 are functional units that constitute one optical communication device.

[0019] The optical SW10 is connected to a plurality of optical transmission paths and outputs an optical signal input from any one of the optical transmission paths to other optical transmission paths. The optical transmission path is, for example, an optical fiber. The optical SW10 has a plurality of first ports (for example, n first ports) and a plurality of second ports (for example, n or more second ports). Each first port of the optical SW10 is connected to a subscriber device 16 via a transmission path 18. FIG. 1 shows an example in which a subscriber device 16-1 is connected to the optical SW10-1 via an optical transmission path 18-1. The optical SW10 is an aspect of the first optical switch.

[0020] Among the plurality of second ports of the optical SW10, n second ports are connected to the folding transfer unit 14 via n optical transmission paths. The remaining second ports of the plurality of second ports of the optical SW10 may be connected to other devices via optical transmission paths. In the following description, for the sake of simplicity of explanation, it is assumed that the number of first ports and second ports of the optical SW10 is n.

[0021] The optical switch 11 is connected to multiple optical transmission lines and outputs optical signals input from one optical transmission line to other optical transmission lines. The optical switch 11 has multiple first ports (e.g., n first ports) and multiple second ports (e.g., n or more second ports). Each first port of the optical switch 11 is connected to a subscriber device 16 via a transmission line 18. Figure 1 shows an example where a subscriber device 16-2 is connected to optical switch 11-1 via optical transmission line 18-2, and a subscriber device 16-3 is connected to optical switch 11-P via optical transmission line 18-3. The optical switch 11 is one embodiment of a second optical switch.

[0022] Of the multiple second ports of the optical switch 11, n second ports are connected to the loopback transfer unit 14 via n optical transmission lines. The remaining second ports of the optical switch 11 may be connected to other devices via optical transmission lines. For the sake of simplicity, in the following description, the number of first and second ports of the optical switch 11 is assumed to be n.

[0023] The subscriber device 16 is connected to the optical SW 10 or 11 by an optical access network such as a PON (Passive Optical Network). The subscriber device 16 includes an optical transceiver. The optical transceiver is an example of an optical transmitter and optical receiver in the subscriber device 16. The optical transceiver is a tunable optical transceiver. In this case, the subscriber device 16 can communicate at any wavelength. The optical transceiver may also be an optical transceiver with AMCC (Auxiliary Management and Control Channel) functionality. In this case, the wavelength used by the subscriber device 16 is controlled via a control signal superimposed by the AMCC. The subscriber device 16 is one embodiment of the first and second devices.

[0024] The control unit 12 is connected to the second port of each optical switch 10 and 11 via an optical transmission path. The control unit 12 comprises a wavelength management control unit 121 and an optical switch control unit 122. The wavelength management control unit 121 assigns wavelengths to each subscriber device 16. When the wavelength management control unit 121 assigns wavelengths to each subscriber device 16, the optical switch control unit 122 switches the path between the ports of the optical switches 10 or 11 so that the subscriber device 16 and the wavelength management control unit 121 are connected.

[0025] The optical switch control unit 122 switches the connections between the ports of the optical switch 10 and the optical switch 11. For example, the optical switch control unit 122 switches the connections between the ports of the optical switch 10 and the optical switch 11 so that the subscriber device 16 can communicate with the desired subscriber device 16.

[0026] The control unit 12 stores a management table. The management table includes information identifying the subscriber device 16, information on the wavelength assigned to each subscriber device 16, and information on the optical SW 10 or 11 to which the subscriber device 16 is connected (for example, information on the port to which the subscriber device 16 is connected). The control unit 12 is composed of one or more processors.

[0027] The loopback transfer unit 14 receives the optical signal output from the optical switch 10 as input and transfers the input optical signal to at least the optical switch 11 to which the destination subscriber device 16 is connected. Since n optical transmission paths are connected from one optical switch 10 to the loopback transfer unit 14, nP upstream optical transmission paths are connected to the loopback transfer unit 14. Furthermore, since n optical transmission paths are connected from one optical switch 11 to the loopback transfer unit 14, nP downstream optical transmission paths are connected to the loopback transfer unit 14. The loopback transfer unit 14 is one embodiment of a transfer unit.

[0028] When performing loopback communication across optical switches 10, the optical switch control unit 122 switches the path between the ports of optical switches 10 so that the output destination of the optical signal from optical switch 10 is connected to the loopback transfer unit 14. The loopback transfer unit 14 controls the input optical signal so that it is output to the desired optical switch 11. With this configuration, loopback communication between any optical switches is realized while keeping the number of wires required for loopback at each optical switch to n.

[0029] When the loopback transfer section 14 is implemented in a single device, a WSS (Wavelength Selective Switch), fiber cross-connect (FXC), or circulating AWG (Arrayed Waveguide Gratings) with nP x nP ports is used. However, WSS and fiber cross-connects with nP x nP ports are difficult to implement when nP is large, and this also leads to increased costs. Therefore, the following explanation will also describe the case where the loopback transfer section 14 is configured with multiple devices.

[0030] Figure 2 is a block diagram showing a specific example of the functional configuration (part 1) of the loopback transfer unit 14 in the first embodiment. The loopback transfer unit 14 comprises a WSS141, a WSS142, and a transfer wavelength control unit 143. The WSS141 is connected to n optical transmission lines (a total of nP optical transmission lines) connected to the second port of each optical SW10, and outputs an optical signal with a wavelength set by the transfer wavelength control unit 143 (hereinafter referred to as the "set wavelength") from among the optical signals transmitted through a certain optical transmission line to the WSS142. The WSS141 is a wavelength-selective optical switch. The number of ports required for the WSS141 is n × P. The WSS141 is one embodiment of the first multiplexing / decoupling unit.

[0031] The WSS142 is connected to n optical transmission lines (a total of nP optical transmission lines) connected to the second port of each optical SW11, and outputs the optical signal of the set wavelength output from the WSS141 to the optical transmission line that becomes the output path for the set wavelength. The WSS142 is a wavelength-selective optical switch. The number of ports required for the WSS142 is n × P. The WSS142 is one embodiment of the second multiplexing / decoupling unit.

[0032] The transfer wavelength control unit 143 sets the wavelength to be output by WSS 141 and 142 according to instructions from the control unit 12. Specifically, when the control unit 12 instructs the transfer wavelength control unit 143 to transfer a wavelength during loopback communication, it sets the specified wavelength to WSS 141 and 142. This allows WSS 141 and 142 to output an optical signal of the set wavelength. The transfer wavelength control unit 143 may be implemented in the control unit 12.

[0033] Figure 3 is a sequence diagram illustrating the processing flow of the optical communication system 1 in the first embodiment. Figure 3 illustrates the case where subscriber device 16-1, which is connected to optical SW 10-1 shown in Figure 1, and subscriber device 16-2, which is connected to optical SW 11-1, communicate with each other. Here, it is assumed that the wavelength λ1 is assigned to subscriber device 16-1 and subscriber device 16-2.

[0034] The transfer wavelength control unit 143 is configured to transfer wavelength λ1 at the ports used between WSS141 and optical SW10-1 and between WSS142 and optical SW11-1 (step S101). The subscriber device 16-1 transmits an optical signal of wavelength λ1 (step S102). The optical signal of wavelength λ1 transmitted from the subscriber device 16-1 is input to the first port of optical SW10-1 via the optical transmission path 18-1.

[0035] In the optical switch 10-1, the optical switch control unit 122 controls the connection between the first port of the optical switch 10-1 to which the subscriber device 16-1 is connected and the second port of the optical switch 10-1 to which the loopback transfer unit 14 is connected. As a result, the optical signal with wavelength λ1 input to the first port of the optical switch 10-1 is output to the loopback transfer unit 14 from the second port (step S103).

[0036] The optical signal with wavelength λ1 output from the optical SW10-1 is input to WSS141 (step S104). WSS141 outputs an optical signal with the set wavelength set by the transfer wavelength control unit 143 to WSS142 (step S105). Here, since wavelength λ1 is set as the set wavelength, an optical signal with wavelength λ1 is output from WSS141. The optical signal with wavelength λ1 output from WSS141 is input to WSS142 (step S106).

[0037] In WSS142, the optical signal of the set wavelength, as set by the transfer wavelength control unit 143, is output to the optical transmission path to which the optical SW11-1 is connected (step S107). Here, since wavelength λ1 is set as the set wavelength, an optical signal of wavelength λ1 is output from WSS142. The optical signal of wavelength λ1 output from WSS142 is input to the second port of optical SW11-1 via the optical transmission path.

[0038] In the optical switch 11-1, the optical switch control unit 122 controls the connection between the first port of the optical switch 11-1 to which the subscriber device 16-2 is connected and the second port of the optical switch 11-1 to which the loopback transfer unit 14 is connected. As a result, the optical signal of wavelength λ1 input to the second port of the optical switch 11-1 is output from the first port to the subscriber device 16-2 via the optical transmission path 18-2 (step S108). The subscriber device 16-2 receives the optical signal of wavelength λ1 output from the optical switch 11-1 (step S109).

[0039] If one or more loopback communications have already been performed and another loopback communication is to be performed, the same wavelength cannot be used between WSS141 and WSS142. Therefore, if the wavelength used for the new loopback communication is the same wavelength, the transfer wavelength control unit 143 outputs a wavelength change command to the wavelength management control unit 121. The wavelength change command is an instruction to change the wavelength used by the subscriber device 16. In response to the wavelength change command, the wavelength management control unit 121 notifies the target subscriber device 16 to communicate using a different wavelength (for example, λ2) than the wavelength already used for loopback communication by the subscriber device 16. This makes it possible to perform loopback communication using a different wavelength even when a new loopback communication is performed.

[0040] With the optical communication system 1 configured as described above, when performing loopback communication in an optical communication system 1 equipped with multiple optical switches 10 and 11, the number of wires required for loopback at each optical switch can be reduced to n. Therefore, it becomes possible for each subscriber device to connect to any other subscriber device at any time using fewer loopback transmission paths than in the conventional method.

[0041] (Modified version of the first embodiment) An amplifier may be provided between WSS141 and WSS142.

[0042] The loopback transfer unit 14 may have the configuration shown in Figure 4 or Figure 5. Figure 4 is a block diagram showing a specific example of the functional configuration (part 2) of the loopback transfer unit 14 in the first embodiment. The loopback transfer unit 14 comprises a WSS 141, a transfer wavelength control unit 143, and an AWG 144. The configuration shown in Figure 4 differs from the configuration shown in Figure 2 in that the control target of the transfer wavelength control unit 143 is the WSS 141, and the AWG 144 is newly provided in place of the WSS 142.

[0043] In the configuration shown in Figure 4, the transfer wavelength control unit 143 sets the wavelength to be output only to the WSS 141. The AWG 144 is connected to n optical transmission paths (a total of nP optical transmission paths) connected to the second port of each optical SW 11, and outputs the optical signal output from the WSS 141 through a path corresponding to the wavelength. Here, while the AWG is less expensive than the WSS, its output port and the wavelength that can be output from that port are fixed. Therefore, it is necessary to control the wavelength according to the partner in the loopback communication. The AWG 144 is one embodiment of the second multiplexing and decoupling unit.

[0044] For example, when subscriber equipment 10-1 connected to optical SW 10-1 and subscriber equipment 16-2 connected to optical SW 11-1 perform loopback communication, the wavelengths that can be transmitted on the port used between AWG 144 and optical SW 11-1 are fixed. The wavelength management control unit 121 sets the transmission wavelength of subscriber equipment 16-1 to a wavelength that can be transmitted on the port used between AWG 144 and optical SW 11-1. Furthermore, the transmission wavelength control unit 143 sets the port used between WSS 141 and optical SW 10-1 to enable the transmission of wavelengths that can be transmitted on the port used between AWG 144 and optical SW 11-1. This makes it possible to achieve loopback communication.

[0045] In the configuration shown in Figure 2, AWG144 may be newly provided in place of WSS141. The transmission wavelength control unit 143 only needs to set the wavelength to be output only to WSS142. In this case, AWG144 is connected to n optical transmission paths (a total of nP optical transmission paths) connected to the second port of each optical SW10, and inputs the optical signals output from each optical SW10 through a path corresponding to the wavelength. For example, when subscriber equipment 10-1 connected to optical SW10-1 and subscriber equipment 16-2 connected to optical SW11-1 perform loopback communication, the wavelengths that can be transmitted at the port used between AWG144 and optical SW10-1 are fixed. The wavelength management control unit 121 sets the transmission wavelength of subscriber equipment 16-1 to a wavelength that can be transmitted at the port used between AWG144 and optical SW10-1. Furthermore, the transfer wavelength control unit 143 configures WSS142 so that the wavelengths transferable on the port used between WSS142 and optical SW11-1 can be transferred on the port used between AWG144 and optical SW10-1. This makes it possible to achieve loopback communication. An amplifier may be provided between WSS141 and AWG144.

[0046] Next, another example will be explained using Figure 5. Figure 5 is a block diagram showing a specific example of the functional configuration (part 3) of the loopback transfer unit 14 in the first embodiment. The loopback transfer unit 14 comprises an AWG 144, a coupler 145, and an amplifier 146. The coupler 145 is connected to n optical transmission lines (a total of nP optical transmission lines) connected to the second port of each optical SW 10, and takes an optical signal transmitted on any of the nP optical transmission lines as input. The coupler 145 combines the input optical signals and outputs them. The coupler 145 is one embodiment of the first multiplexing unit.

[0047] Amplifier 146 amplifies the optical signal output from coupler 145. AWG 144 is connected to n optical transmission lines (a total of nP optical transmission lines) connected to the second port of each optical SW 11, and outputs the optical signal amplified by amplifier 146 to the optical transmission lines after demultiplexing. Couplers are less expensive than WSS and do not require control by the transfer wavelength control unit 143. Note that if the branch loss is relatively small, amplifier 146 may not be necessary.

[0048] (Second embodiment) In the second embodiment, the system configuration of the optical communication system 1 is the same as in the first embodiment, except that the configuration of the loopback transfer unit 14 is different. Therefore, the differences from the first embodiment will be explained below.

[0049] Figure 6 is a block diagram showing a specific example of the functional configuration (part 1) of the loopback transfer unit 14a in the second embodiment. The loopback transfer unit 14a comprises a plurality of WSS141-1 to 141-X (where X is an integer of 2 or more), a plurality of WSS142-1 to 142-X, a transfer wavelength control unit 143a, and a plurality of upper-level WSS147-1 to 147-2. In the example shown in Figure 6, WSS141-x (1 ≤ x ≤ X) is connected to upper-level WSS147-1, and WSS142-x is connected to upper-level WSS147-2.

[0050] Each WSS141-x is connected to n different optical transmission lines (a total of nP optical transmission lines) out of the n optical transmission lines connected to the second port of each optical SW10. It outputs the optical signal of a set wavelength from the optical signals transmitted through a particular optical transmission line to the higher-level WSS147. In this way, each WSS141 is connected to approximately the same number of optical transmission lines on average. For example, if there are two WSS141s (X=2), three optical SW10s (P=3), and the number of optical transmission lines connected to the second port of each optical SW10 is 2 (n=2), then each WSS141 will be connected to three different optical transmission lines. The number of ports required for a WSS141 is n × P / X.

[0051] Each WSS142-x is connected to nP / X different optical transmission lines and outputs the optical signal of a set wavelength, output from the higher-level WSS147-2, to the optical transmission line that will be the output path for that set wavelength. In this way, each WSS142 is connected to approximately the same number of optical transmission lines on average. The number of ports required for a WSS142 is n × P / X.

[0052] The upper-level WSS147-1 outputs the optical signal of a set wavelength from each WSS141 to the upper-level WSS147-2. The number of ports required for the upper-level WSS147-1 is X.

[0053] The upper-level WSS147-2 outputs the optical signal of a set wavelength from the optical signal output from the upper-level WSS147-1 to each WSS142. The number of ports required for the upper-level WSS147-2 is X.

[0054] The transfer wavelength control unit 143a sets the wavelengths to be output by WSS141, 142 and the higher-level WSS147, according to instructions from the control unit 12. The transfer wavelength control unit 143a may be implemented in the control unit 12.

[0055] In the optical communication system 1 of the second embodiment configured as described above, X WSS141 and WSS142 are arranged in parallel, and a higher-level WSS147 is placed above each of the parallel-arranged WSS141 and WSS142. With this configuration, it is possible to reduce the number of ports required per WSS compared to the first embodiment.

[0056] (Modified version of the second embodiment) Amplifiers may be provided between WSS141-x and the upper WSS147-1, between the upper WSS147-1 and the upper WSS147-2, and between WSS142-x and the upper WSS147-2, or all of these.

[0057] The loopback transfer unit 14a may have the configuration shown in Figure 7 or Figure 8. Figure 7 is a block diagram showing a specific example of the functional configuration (part 2) of the loopback transfer unit 14a in the second embodiment. The loopback transfer unit 14a comprises a plurality of WSS141-1 to 141-X, a transfer wavelength control unit 143a, a plurality of AWG144-1 to 144-X, and a plurality of upper-level WSS147-1 to 147-2. In the example shown in Figure 7, WSS141-1 to 141-X are connected to upper-level WSS147-1, and AWG144-1 to 144-X are connected to upper-level WSS147-2.

[0058] The configuration shown in Figure 7 differs from the configuration shown in Figure 6 in that the transfer wavelength control unit 143a controls WSS141, 142, and the higher-level WSS147-1, and that multiple AWG144-1 to 144-X units are newly provided instead of multiple WSS142-1 to 142-X units. WSS141 and the higher-level WSS147 perform the same processing as the functional units of the same name shown in Figure 6, so their explanation is omitted.

[0059] AWG144-x is connected to n different optical transmission paths (a total of nP optical transmission paths) out of the n optical transmission paths connected to the second port of each optical SW11, and outputs the optical signal of the set wavelength output from the upper WSS147-2 through the path corresponding to the wavelength. The number of ports required for AWG144 is n × P / X.

[0060] Amplifiers may be provided between WSS141-x and the upper WSS147-1, between the upper WSS147-1 and the upper WSS147-2, and between AWG144-x and the upper WSS147-2, or all of these.

[0061] In the configuration shown in Figure 6, AWG144-1 to 144-X may be newly provided in place of WSS141-1 to 141-X.

[0062] Next, we will explain another example using Figure 8. Figure 8 is a block diagram showing a specific example of the functional configuration (part 3) of the loopback transfer unit 14a in the second embodiment. The loopback transfer unit 14a comprises multiple AWGs 144-1 to 144-X, multiple couplers 145-1 to 145-X, an amplifier 146, multiple amplifiers 148-1 to 148-X, multiple upstream couplers 149-1 to 149-2, and multiple amplifiers 150-1 to 150-X.

[0063] In the example shown in Figure 8, coupler 145-x is connected to upper coupler 149-1 via amplifier 148-x, AWG144-x is connected to upper coupler 149-2 via amplifier 150-x, and upper coupler 149-1 and upper coupler 149-2 are connected via amplifier 146.

[0064] Coupler 145-x is connected to n different optical transmission lines (a total of nP optical transmission lines) out of the n optical transmission lines connected to the second port of each optical SW10, and takes the optical signal transmitted through any of the nP / X optical transmission lines as input. Coupler 145-x combines the input optical signal and outputs it.

[0065] Amplifier 148-x amplifies the optical signal output from coupler 145-x.

[0066] The upper coupler 149-1 combines the optical signals amplified by each amplifier 148 and outputs them.

[0067] The upper coupler 149-2 branches the optical signal output from the upper coupler 149-1 and amplified by the amplifier 146.

[0068] Amplifier 150-x amplifies the optical signal output from the upper coupler 149-2.

[0069] The AWG144-x is connected to n different optical transmission paths (a total of nP optical transmission paths) out of the n optical transmission paths connected to the second port of each optical SW11, and outputs the optical signal amplified by each amplifier 146 through a path corresponding to the wavelength. The number of ports required for the AWG144-x is n × P / X.

[0070] (Third embodiment) In the third embodiment, the system configuration of the optical communication system 1 is the same as in the first embodiment, except that the configuration of the loopback transfer unit 14 is different. Therefore, the differences from the first embodiment will be explained below.

[0071] Figure 9 is a block diagram showing a specific example of the functional configuration (part 1) of the loopback transfer unit 14b in the third embodiment. The loopback transfer unit 14b comprises multiple WSS141-1 to 141-X, multiple WSS142-1 to 142-X, a transfer wavelength control unit 143b, multiple upper-level WSS147-1-1 to 147-1-X, and multiple upper-level WSS147-2-1 to 147-2-X. In the example shown in Figure 9, WSS141-x is connected to upper-level WSS147-1-x, and WSS142-x is connected to upper-level WSS147-2-x.

[0072] The WSS141-x is connected to n different optical transmission paths (a total of nP optical transmission paths) out of the n optical transmission paths connected to the second port of each optical SW10, and outputs the optical signal of a set wavelength from among the optical signals transmitted through a particular optical transmission path to the higher-level WSS147-x.

[0073] The WSS142-x is connected to different nP / X optical transmission lines and outputs the optical signal of a set wavelength output from the higher-level WSS147-2-x to the optical transmission line that will be the output path for the set wavelength.

[0074] The higher-level WSS147-1-x outputs the optical signal with a set wavelength from the optical signal output from WSS141-x to the higher-level WSS147-2.

[0075] The upper WSS147-2-x outputs the optical signal with a set wavelength from the optical signal output from the upper WSS147-1 to WSS142-x.

[0076] The transfer wavelength control unit 143b sets the wavelengths to be output by WSS141, 142 and the higher-level WSS147 according to the instructions of the control unit 12. The transfer wavelength control unit 143b may be implemented in the control unit 12.

[0077] In the optical communication system 1 of the third embodiment configured as described above, in addition to X WSS141 and WSS142, X higher-level WSS147-1 and higher-level WSS147-2 are also arranged in parallel. In the second embodiment, it was necessary to aggregate a maximum of nP wavelengths in the higher-level WSS147. In contrast, in the third embodiment, the maximum number of wavelengths accommodated by all WSSs is nP / X, making it possible to reduce the number of wavelengths that must be accommodated by a single WSS.

[0078] (Modified version of the third embodiment) Amplifiers may be provided between WSS141-x and the upper WSS147-1-x, between the upper WSS147-1 and the upper WSS147-2, and between WSS142-x and the upper WSS147-2-x, or all of them.

[0079] The loopback transfer unit 14b may have the configuration shown in Figure 10 or Figure 11. Figure 10 is a block diagram showing a specific example of the functional configuration (part 2) of the loopback transfer unit 14b in the third embodiment. The loopback transfer unit 14b comprises a plurality of WSS 141-1 to 141-X, a transfer wavelength control unit 143b, a plurality of AWG 144-1 to 144-X, a plurality of upper WSS 147-1-1 to 147-1-X, and a plurality of upper WSS 147-2-1 to 147-2-X.

[0080] In the example shown in Figure 10, WSS141-x is connected to the upper WSS147-1-x, and AWG144-x is connected to the upper WSS147-2-x. The configuration shown in Figure 10 differs from the configuration shown in Figure 9 in that the transmission wavelength control unit 143b controls WSS141 and the upper WSS147, and multiple AWG144-1 to 144-X are newly provided instead of multiple WSS142-1 to 142-X. WSS141, upper WSS147, and upper WSS147 perform the same processing as the functional units of the same name shown in Figure 9, so their explanation is omitted.

[0081] The AWG144-x is connected to n different optical transmission paths (a total of nP optical transmission paths) out of the n optical transmission paths connected to the second port of each optical SW11, and outputs the optical signal of the set wavelength output from the upper WSS147-2-x through the path corresponding to the wavelength. The number of ports required for the AWG144-x is n × P / X.

[0082] Amplifiers may be provided between WSS141-x and the upper WSS147-1-x, between the upper WSS147-1 and the upper WSS147-2, and between AWG144-x and the upper WSS147-2-x, or all of these.

[0083] In the configuration shown in Figure 9, AWG144-1 to 144-X may be newly provided in place of WSS141-1 to 141-X.

[0084] Next, another example will be explained using Figure 11. Figure 11 is a block diagram showing a specific example of the functional configuration (part 3) of the loopback transfer unit 14b in the third embodiment. The loopback transfer section 14b comprises multiple AWGs 144-1 to 144-X, multiple couplers 145-1 to 145-X, multiple amplifiers 146-1 to 146-XX, multiple amplifiers 148-1 to 148-X, multiple upper couplers 149-1 to 149-1-X, multiple upper couplers 149-2-1 to 149-2-X, and multiple amplifiers 150-1 to 150-X.

[0085] In the example shown in Figure 11, coupler 145-x is connected to upper coupler 149-1-x via amplifier 148-x, AWG144-x is connected to upper coupler 149-2-x via amplifier 150-x, and upper coupler 149-1 and upper coupler 149-2 are connected via amplifier 146.

[0086] Coupler 145-x is connected to n different optical transmission lines (a total of nP optical transmission lines) out of the n optical transmission lines connected to the second port of each optical SW10, and takes the optical signal transmitted through any of the nP / X optical transmission lines as input. Coupler 145-x combines the input optical signal and outputs it.

[0087] Amplifier 148-x amplifies the optical signal output from coupler 145-x.

[0088] The upper coupler 149-1-x branches and outputs the optical signal amplified by the amplifier 148-x.

[0089] The upper coupler 149-2-x combines the optical signals output from each upper coupler 149-1 and amplified by the connected amplifier 146.

[0090] Amplifier 150-x amplifies the optical signal output from the upper coupler 149-2-x.

[0091] AWG144-x is connected to n different optical transmission paths (a total of nP optical transmission paths) out of the n optical transmission paths connected to the second port of each optical SW11, and outputs the optical signal amplified by amplifier 146-x through a path corresponding to the wavelength. The number of ports required for AWG144-x is n × P / X.

[0092] (Modifications common to the first to third embodiments) In the embodiments described above, separate optical switches are used for the upward and downward directions, but the same optical switch may be used for both the upward and downward directions.

[0093] In each of the above embodiments, a configuration is shown in which the optical SW10, optical SW11, or the loopback transfer units 14, 14a, and 14b are provided in a single optical communication device. Any of the optical SW10, optical SW11, or the loopback transfer units 14, 14a, and 14b may be implemented in other devices.

[0094] Some of the functional units (for example, the control unit 12, and the loopback transfer units 14, 14a, and 14b) of the optical communication device in the above-described embodiment may be implemented using a computer. In that case, the program for implementing this function may be recorded on a computer-readable recording medium, and the program recorded on this recording medium may be loaded into a computer system and executed. The term "computer system" as used herein includes hardware such as an operating system and peripheral devices.

[0095] Furthermore, "computer-readable recording media" refers to portable media such as flexible disks, magneto-optical disks, ROMs, and CD-ROMs, as well as storage devices such as hard disks built into computer systems. In addition, "computer-readable recording media" may also include those that dynamically hold programs for a short period of time, such as communication lines used when transmitting programs over networks such as the Internet or communication lines such as telephone lines, and those that hold programs for a certain period of time, such as volatile memory inside computer systems that act as servers or clients in such cases. Moreover, the above-mentioned programs may be for the purpose of realizing some of the functions described above, or they may be able to realize the above-mentioned functions in combination with programs already recorded in the computer system, or they may be realized using programmable logic devices such as FPGAs.

[0096] While embodiments of this invention have been described in detail above with reference to the drawings, the specific configuration is not limited to these embodiments and includes designs and the like that do not depart from the spirit of this invention. [Industrial applicability]

[0097] This invention can be applied to optical communication system technology that performs loopback communication via an optical switch. [Explanation of Symbols]

[0098] 10-1~10-P, 11-1~11-P…Optical SW, 12…Control Unit, 121…Wavelength Management Control Unit, 122…Optical SW Control Unit, 14, 14a, 14b…Loopback Transfer Unit, 16-1~16-3…Subscriber Equipment, 141, 141-1~141-X, 142, 142-1~142-X…WSS, 143, 143a, 143b…Transfer Wavelength Control Unit, 144, 144-1~144-X…AWG, 145, 145-1~145-X…Coupler, 146, 146-1-1~146-XX, 148-1~148-X, 150-1~150-X…Amplifier, 147-1, 147-2, 147-1-1~147-1-X, 147-2-1~147-2-X... Upper WSS, 149-1, 149-2, 149-1-1~149-1-X, 149-2-1~149-2-X... Upper Coupler

Claims

1. An optical communication device, A first optical switch having multiple first ports and multiple second ports, which outputs an optical signal input from any of the multiple first ports from any of the multiple second ports, A second optical switch having multiple first ports and multiple second ports, which outputs an optical signal input from one of the multiple second ports from one of the multiple first ports, A transfer unit that transfers an optical signal output from any of the plurality of second ports of the first optical switch to any of the plurality of second ports of the second optical switch, Equipped with, Of the plurality of second ports of the first optical switch, some second ports are connected to the transfer unit, and the remaining second ports of the first optical switch are connected to other devices. An optical communication device in which some of the plurality of second ports of the second optical switch are connected to the transfer unit, and the remaining second ports of the second optical switch are connected to other devices.

2. Communication between subscriber devices connected under the control of this device is performed via loopback communication using the second port of the first optical switch that is connected to the transfer unit among the plurality of second ports, and the second port of the second optical switch that is connected to the transfer unit among the plurality of second ports. The optical communication device according to claim 1.

3. The transfer unit is, A first wavelength-selective optical switch that outputs an optical signal of a set wavelength from among the optical signals output from any of the plurality of second ports of the first optical switch, A second wavelength-selective optical switch outputs an optical signal of a set wavelength from the optical signal output from the first wavelength-selective optical switch to one of the plurality of second ports of the second optical switch, Equipped with, The optical communication device according to claim 1 or 2.

4. The first optical switch and the second optical switch may be different optical switches or the same optical switch. The optical communication device according to claim 1 or 2.

5. The first optical switch and the second optical switch may be different optical switches or the same optical switch. The optical communication device according to claim 3.

6. The plurality of first ports of the first optical switch and the plurality of first ports of the second optical switch are connected to different subscriber devices via an optical transmission path. The optical communication device according to claim 1 or 2.

7. The plurality of first ports of the first optical switch and the plurality of first ports of the second optical switch are connected to different subscriber devices via an optical transmission path. The optical communication device according to claim 3.

8. The plurality of first ports of the first optical switch and the plurality of first ports of the second optical switch are connected to different subscriber devices via an optical transmission path. The optical communication device according to claim 4.

9. The plurality of first ports of the first optical switch and the plurality of first ports of the second optical switch are connected to different subscriber devices via an optical transmission path. The optical communication device according to claim 5.

10. The first optical switch and the second optical switch are N × M switches (where N and M are integers of 2 or more). The optical communication device according to claim 1 or 2.

11. The first optical switch and the second optical switch are N × M switches (where N and M are integers of 2 or more). The optical communication device according to claim 3.

12. The first optical switch and the second optical switch are N × M switches (where N and M are integers of 2 or more). The optical communication device according to claim 4.

13. The first optical switch and the second optical switch are N × M switches (where N and M are integers of 2 or more). The optical communication device according to claim 5.

14. The first optical switch and the second optical switch are N × M switches (where N and M are integers of 2 or more). The optical communication device according to claim 6.

15. The first optical switch and the second optical switch are N × M switches (where N and M are integers of 2 or more). The optical communication device according to claim 7.

16. The first optical switch and the second optical switch are N × M switches (where N and M are integers of 2 or more). The optical communication device according to claim 8.

17. The first optical switch and the second optical switch are N × M switches (where N and M are integers of 2 or more). The optical communication device according to claim 9.

18. A first optical switch having multiple first ports and multiple second ports, which outputs an optical signal input from any of the multiple first ports from any of the multiple second ports, A second optical switch having multiple first ports and multiple second ports, which outputs an optical signal input from one of the multiple second ports from one of the multiple first ports, An optical communication device comprising: a transfer unit that transfers an optical signal output from any of the plurality of second ports of the first optical switch to any of the plurality of second ports of the second optical switch, Of the plurality of second ports of the first optical switch, some second ports are connected to the transfer unit, and the remaining second ports of the first optical switch are connected to other devices. Of the plurality of second ports of the second optical switch, some second ports are connected to the transfer unit, and the remaining second ports of the second optical switch are connected to other devices, in an optical communication device, When performing the aforementioned transfer, the transfer unit is connected to a second port of any of the plurality of second ports of the first optical switch in order to transfer the optical signal transmitted from the source subscriber device, and the control unit controls the transfer unit to connect to a second port of any of the plurality of second ports of the second optical switch that is the destination of the optical signal, An optical communication system equipped with [the necessary components].

19. The control unit, To enable communication between a subscriber device connected to the first optical switch and a subscriber device connected to the second optical switch, the connections between the plurality of first ports and the plurality of second ports of the first optical switch, and the connections between the plurality of first ports and the plurality of second ports of the second optical switch are switched. The optical communication system according to claim 18.

20. A transfer method performed by an optical communication device, The first optical switch has a plurality of first ports and a plurality of second ports, and outputs an optical signal input from any of the plurality of first ports from any of the plurality of second ports. The second optical switch has a plurality of first ports and a plurality of second ports, and outputs an optical signal input from one of the plurality of second ports from one of the plurality of first ports. The transfer unit transfers the optical signal output from any of the plurality of second ports of the first optical switch to any of the plurality of second ports of the second optical switch. Of the plurality of second ports of the first optical switch, some second ports are connected to the transfer unit, and the remaining second ports of the first optical switch are connected to other devices. A transfer method in which, of the plurality of second ports of the second optical switch, some second ports are connected to the transfer unit, and the remaining second ports of the second optical switch are connected to other devices.

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