OPTICAL NODE DEVICE, OPTICAL COMMUNICATION SYSTEM, AND TRANSFER METHOD

Abstract

An optical node device to which a first subscriber device and a second subscriber device in an optical communication system connect, the first subscriber device being for simplex connection using a differing wavelength for transmission / reception, the second subscriber device being for duplex connection using an identical wavelength for transmission / reception, said optical node device comprising: a transmission / reception separation unit which forwards an optical signal sent from the first subscriber device and an optical signal to be sent to the first subscriber device, without interference therebetween; and an optical switch, the port-to-port connection relations of which are controlled such that the optical signal sent from the first subscriber device or the optical signal to be sent to the first subscriber device passes through the transmission / reception separation unit and an optical signal sent from the second subscriber device or an optical signal to be sent to the second subscriber device does not pass through the transmission / reception separation unit, and which outputs, from another optical transfer path, an optical signal input from a given optical transfer path.　

Description

[Technical field]

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

[0002] Conventionally, a system has been proposed in which a subscriber device communicates with a counterpart subscriber device by optical signals via an optical node device called a photonic gateway. FIG. 12 is a diagram for explaining the configuration of a conventional optical communication system 100. As shown in FIG. 12, the conventional optical communication system 100 includes a plurality of subscriber devices 200-1 to 200-3, a plurality of subscriber devices 300-1 to 300-3, a plurality of optical node devices 350-1 to 350-2, and a plurality of control units 400-1 to 400-2. The optical node device 350-1 and the optical node device 350-2 are connected via an optical communication NW 600 configured by an optical transmission path.

[0003] The section between the subscriber devices 200-1 to 200-3 and the optical node device 350-1, and the section between the subscriber devices 300-1 to 300-3 and the optical node device 350-2 are called optical access sections. The section between the optical node device 350-1 and the optical node device 350-2 is called a relay section. In the example shown in Fig. 12, the subscriber devices 200-1, 200-2 and the optical node device 350-1 are connected by a single-core optical transmission path, and the subscriber device 200-3 and the optical node device 350-1 are connected by a two-core optical transmission path.

[0004] The optical node device 350-1 is composed of an optical SW 500, a plurality of transmission / reception separation units 510-1 to 510-2, and a plurality of wavelength multiplexers / demultiplexers 520-1 to 520-2. The optical node device 350-2 is composed of an optical SW 550, a plurality of transmission / reception separation units 560-1 to 560-2, and a plurality of wavelength multiplexers / demultiplexers 570-1 to 570-2. The control unit 400-1 manages the subscriber device 200 and controls the operation of the optical node device 350-1. The control unit 400-2 manages the subscriber device 300 and controls the operation of the optical node device 350-2.

[0005] Here, consider a state in which the subscriber device 200-1 and the subscriber device 300-1 are communicating with each other. Each of the subscriber devices 200 and 300 is equipped with a wavelength-tunable transceiver. For example, the subscriber device 200-1 transmits an optical signal using a wavelength previously assigned by the subscriber device management control unit 420-1 of the control unit 400-1. Similarly, the subscriber device 300-1 transmits an optical signal using a wavelength previously assigned by the subscriber device management control unit 420-2 of the control unit 400-2. In this way, in the optical communication system 100, communication is performed between the subscriber device 200 and the subscriber device 300 using the wavelength previously assigned by each of the control units 400-1 and 400-2.

[0006] For example, in the subscriber devices 200-1 and 200-2, single-core bidirectional communication is performed within the optical SW 500, 550 in the optical access section and each optical node device 350-1, 350-2. Therefore, between the optical SW 500 and the wavelength multiplexer / demultiplexer 520-1, 520-2, a transmission / reception separator 510-1, 510-2 is provided, which separates or multiplexes the transmission and reception wavelengths. The transmission / reception separators 510-1, 510-2 and the wavelength multiplexers / demultiplexers 520-1, 520-2 are connected by optical transmission paths, respectively.

[0007] Similarly, between the optical SW 550 and the wavelength multiplexers 570-1 and 570-2, there are provided transmission / reception separators 560-1 and 560-2, which separate or multiplex the transmission and reception wavelengths. The transmission / reception separators 560-1 and 560-2 and the wavelength multiplexers 570-1 and 570-2 are connected by optical transmission lines, respectively. Therefore, the repeater sections are connected by two-core optical transmission lines.

[0008] The transmission / reception separator has a transmission characteristic as shown in Fig. 13, for example, and has a function of multiplexing or demultiplexing optical signals of different wavelengths with a certain wavelength as a boundary. Fig. 13 shows an example in which the short wavelength side is the transmission wavelength of the transmission port, and the long wavelength side is the transmission wavelength of the reception port. Note that the relationship between the wavelength and transmission / reception may be reversed to the characteristic shown in Fig. 13. Examples of means for realizing the transmission / reception separator include a wavelength-dependent transmission or reflection filter formed using a multilayer film filter, a PLC (Planar waveguide circuit), and the like.

[0009] In optical communication systems that use general wavelength division multiplexing (WDM) technology, the wavelength intervals assigned to subscriber devices are configured to be equal to the wavelength intervals between each channel of a wavelength multiplexer / demultiplexer. For example, in a general WDM transmission system, wavelength channels are specified with optical frequency intervals of 100 GHz or 50 GHz. The wavelength intervals of the wavelength multiplexer / demultiplexer and the wavelength intervals of the transmitter / receiver are designed to match those wavelength channels.

[0010] 12, the subscriber devices 200-1 and 200-2 are shown to perform single-core bidirectional communication in the optical access section, as in conventional optical access communication. However, in the optical communication system, it is also assumed that the subscriber devices 200-3 and 300-3 are connected by separate optical transmission lines for transmission and reception in the optical access section. In this case, the connection between the optical SW and the wavelength multiplexer / demultiplexer is configured not to go through a transmission / reception separation unit. [Prior art documents] [Non-patent literature]

[0011] [Non-Patent Document 1] Takuya Kanai, Kazuaki Honda, Yasunari Tanaka, Makoto Kaneko, Kazutaka Hara, Junichi Kani, and Tomoaki Yoshida, "Photonic Gateway Supporting All-Photonics Network," IEICE General Conference, B-8-20, March 2021. [Non-Patent Document 2] Kazuaki Honda, “Photonic Gateway for Direct and Protocol-Independent End-to-End User Connections”, OFC2021. Summary of the Invention [Problem to be solved by the invention]

[0012] When the optical access section is configured for one-core bidirectional communication and using a transmission / reception separation unit, the wavelengths of transmission and reception must be sufficiently separated in order to ensure sufficient isolation of the optical signals of transmission and reception. As shown in FIG. 14, the wavelengths are roughly divided into two groups, the short wavelength side and the long wavelength side, and the wavelengths are allocated to transmission and reception, respectively. The example of transmission and reception in FIG. 14 shows the state seen from the subscriber device 200 accommodated in the optical node device 350-1. As a result, the number of wavelength channels that can be used is reduced by half for the effective wavelength range. The "effective wavelength tunable width" is the wavelength tunable width of the wavelength tunable transceiver mounted on the subscriber device, or the operating wavelength range of the wavelength multiplexer / demultiplexer mounted on the optical node device. From the viewpoint of cost, it is desirable for the wavelength tunable transceiver to use the same optical device and configuration for all subscriber devices, and the wavelength tunable range is also the same. In that case, if different wavelengths are used for transmission and reception, the number of available channels is reduced by half or less for the wavelength tunable range of the wavelength tunable transceiver.

[0013] In wavelength allocation by the control unit 400, when the subscriber devices 200 and 300 are configured to use the same wavelength for transmission and reception and to use different wavelengths for transmission and reception, a problem occurs in wavelength allocation. For example, as shown in Fig. 12, when one-core bidirectional communication is performed in an optical access section such as the subscriber devices 200-1 to 200-2 and 300-1 to 300-2, different wavelengths must be used for transmission and reception, whereas when two-core bidirectional communication is performed in an optical access section such as the subscriber devices 200-3 and 300-3, the same wavelength can be used for transmission and reception. In this way, the wavelength management policy for transmission and reception needs to be changed depending on the connection form of the optical access section, which causes a problem of complicated wavelength management.

[0014] In view of the above circumstances, the present invention aims to provide a technology that can easily manage wavelengths in an optical communication system that has a mixture of configurations in which subscriber devices use the same wavelength for transmission and reception and configurations in which subscriber devices use different wavelengths for transmission and reception. [Means for solving the problem]

[0015] One aspect of the present invention is an optical node device to which a first subscriber device and a second subscriber device are connected in an optical communications system in which a first subscriber device, which uses different wavelengths for transmission and reception and is connected via one core, and a second subscriber device, which uses the same wavelength for transmission and reception and is connected via two cores, are connected, the optical node device comprising: a transmit / receive separation unit that transfers an optical signal transmitted from the first subscriber device and an optical signal addressed to the first subscriber device without causing interference between the first subscriber device and the optical signal addressed to the first subscriber device; and an optical switch that controls the connection relationship between ports so that the optical signal transmitted from the first subscriber device or the optical signal addressed to the first subscriber device passes through the transmit / receive separation unit and the optical signal transmitted from the second subscriber device or the optical signal addressed to the second subscriber device does not pass through the transmit / receive separation unit, and that outputs an optical signal input from one optical transmission path from another optical transmission path.

[0016] One aspect of the present invention is an optical communications system comprising a plurality of subscriber devices and an optical node device to which the plurality of subscriber devices are connected, wherein the subscriber device comprises a transmitter that transmits an optical signal, and a transmit / receive separation unit that transfers the optical signal transmitted by the transmitter and the received optical signal without interference, and the optical node device comprises an optical switch in which the connection relationship between ports is controlled so as to output the optical signal transmitted from the subscriber device to a destination optical transmission path, and to output the optical signal addressed to the subscriber device to the subscriber device.

[0017] One aspect of the present invention is a transfer method performed by an optical node device to which a first subscriber device and a second subscriber device are connected in an optical communications system in which a first subscriber device, which uses different wavelengths for transmission and reception and is connected via one core, and a second subscriber device, which uses the same wavelength for transmission and reception and is connected via two cores, are mixed, in which a transmit / receive separation unit transfers an optical signal transmitted from the first subscriber device and an optical signal addressed to the first subscriber device without causing interference, the connection relationship between ports is controlled so that the optical signal transmitted from the first subscriber device or the optical signal addressed to the first subscriber device passes through the transmit / receive separation unit and the optical signal transmitted from the second subscriber device or the optical signal addressed to the second subscriber device does not pass through the transmit / receive separation unit, and an optical signal input from one optical transmission path is output from another optical transmission path. Effect of the Invention

[0018] According to the present invention, it becomes possible to easily manage wavelengths in an optical communication system in which a configuration in which subscriber devices use the same wavelength for transmission and reception and a configuration in which subscriber devices use different wavelengths for transmission and reception are mixed. [Brief description of the drawings]

[0019] [Figure 1] 1 is a diagram illustrating a configuration of an optical communication system according to a first embodiment. [Diagram 2] FIG. 2 is a diagram illustrating an example of a wavelength allocation in the first embodiment. [Diagram 3] FIG. 4 is a diagram illustrating another example of a wavelength allocation in the first embodiment. [Figure 4] FIG. 4 is a sequence diagram for explaining a process flow of the optical communication system in the first embodiment. [Diagram 5] FIG. 11 is a diagram illustrating an example of a wavelength allocation in the second embodiment. [Figure 6] FIG. 13 is a diagram illustrating a configuration of an optical communication system according to a third embodiment. [Figure 7] FIG. 13 is a diagram illustrating a configuration of a transmission / reception separator in the third embodiment. [Figure 8] 5 is a diagram illustrating an example of the transmission characteristics of a first optical filter and a second optical filter. FIG. [Figure 9] FIG. 13 is a diagram illustrating a configuration of an optical communication system according to a fourth embodiment. [Figure 10] FIG. 13 is a diagram illustrating a configuration of an optical communication system according to a fifth embodiment. [Figure 11] FIG. 13 is a diagram illustrating an example of the configuration of a subscriber device in the fifth embodiment. [Figure 12] FIG. 1 is a diagram for explaining the configuration of a conventional optical communication system. [Figure 13] 11 is a diagram for explaining the transmission characteristics of a transmission / reception separator; FIG. [Figure 14] FIG. 1 is a diagram showing an example of a wavelength allocation according to a conventional technique. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0020] Hereinafter, an embodiment of the present invention will be described with reference to the drawings. (First embodiment) Fig. 1 is a diagram showing a configuration of an optical communication system 1 in the first embodiment. The optical communication system 1 includes a plurality of optical node devices 10, 15, a plurality of subscriber devices 20-1 to 20-3, a plurality of subscriber devices 30-1 to 30-3, and a plurality of control units 40-1 to 40-2. The number of subscriber devices 20 and 30 may be two or more. The configuration of the optical communication system 1 is basically the same as the configuration shown in Fig. 12 except for the configurations of the optical node devices 10 and 15.

[0021] The optical node device 10 and each subscriber device 20, and the optical node device 15 and each subscriber device 30 are connected by optical transmission paths. The optical transmission paths are, for example, optical fibers. The optical node device 10 and the optical node device 15 are connected via an optical communication NW 60 configured by the optical transmission paths.

[0022] In the following description, the section between the subscriber devices 20-1 to 20-3 and the optical node device 10, and the section between the subscriber devices 30-1 to 30-3 and the optical node device 15 are described as optical access sections, and the section between the optical node device 10 and the optical node device 15 is described as a relay section. In the example shown in Fig. 1, each of the subscriber devices 20-1, 20-2 and the optical node device 10 are connected by a single-core optical transmission line, and the subscriber device 20-3 and the optical node device 10 are connected by a two-core optical transmission line. Similarly, each of the subscriber devices 30-1, 30-2 and the optical node device 15 are connected by a single-core optical transmission line, and the subscriber device 30-3 and the optical node device 15 are connected by a two-core optical transmission line.

[0023] The optical node device 10 is composed of an optical SW 50, a plurality of transmission / reception separators 51-1 to 51-2, and a plurality of wavelength multiplexers / demultiplexers 52-1 to 52-2. In the first embodiment, the optical node device 10 differs from the conventional configuration in that it uses a transmission / reception separator that does not have wavelength dependency, instead of a transmission / reception separator that separates optical signals by wavelength as used in the conventional technology. An example of a transmission / reception separator that does not have wavelength dependency is a circulator. Not having wavelength dependency means that the function is not affected by the wavelength. A transmission / reception separator that does not have wavelength dependency can transfer optical signals regardless of the wavelength.

[0024] The optical SW50 is an optical switch having M (M is an integer of 2 or more) ports 5 and O (O is an integer of 2 or more) ports 6. In this embodiment, the numbers M and O are described as 5. An optical signal input to a port of the optical SW50 is output from another port. For example, an optical signal input to port 5 of the optical SW50 is output from port 6. The connection relationship between ports 5 and 6 of the optical SW50 is set under the control of the control unit 40-1.

[0025] Subscriber device 20-1 is connected to port 5-2 of optical SW50 via an optical transmission line, subscriber device 20-2 is connected to port 5-3 of optical SW50 via an optical transmission line, and subscriber device 20-3 is connected to ports 5-4 and 5-5 of optical SW50 via optical transmission lines.

[0026] A control unit 40-1 is connected to port 6-1 of the optical SW50 via an optical transmission line, a transmit / receive separation unit 51-1 is connected to port 6-2 of the optical SW50 via an optical transmission line, a wavelength multiplexer / demultiplexer 52-2 is connected to port 6-3 of the optical SW50 via an optical transmission line, a transmit / receive separation unit 51-2 is connected to port 6-4 of the optical SW50 via an optical transmission line, and a wavelength multiplexer / demultiplexer 52-1 is connected to port 6-5 of the optical SW50 via an optical transmission line.

[0027] The transmission / reception separators 51-1 to 51-2 are, for example, circulators. The transmission / reception separators 51-1 to 51-2 have at least three or more ports. In the following description, it is assumed that the transmission / reception separators 51-1 to 51-2 have three ports. A first port 53-1 of the transmission / reception separator 51-1 is connected to a port 6 (port 6-2 in FIG. 1) of the optical SW 50. A second port 53-2 of the transmission / reception separator 51-1 is connected to a wavelength multiplexer / demultiplexer 52-2. A third port 53-3 of the transmission / reception separator 51-1 is connected to a wavelength multiplexer / demultiplexer 52-1. An optical signal input to the first port 53-1 is output from the second port 53-2. An optical signal input to the second port 53-2 is output from the third port 53-3. An optical signal input to the third port 53-3 is output from the first port 53-1.

[0028] Similarly, a first port 54-1 of the transmission / reception separator 51-2 is connected to port 6 (port 6-4 in FIG. 1) of the optical SW 50. A second port 54-2 of the transmission / reception separator 51-2 is connected to the wavelength multiplexer / demultiplexer 52-2. A third port 54-3 of the transmission / reception separator 51-2 is connected to the wavelength multiplexer / demultiplexer 52-1. An optical signal input to the first port 54-1 is output from the second port 54-2. An optical signal input to the second port 54-2 is output from the third port 54-3. An optical signal input to the third port 54-3 is output from the first port 54-1.

[0029] In this way, the transmission / reception separators 51-1 to 51-2 have directionality and port selectivity but are not wavelength-dependent. Therefore, the optical signal output by the subscriber device 20 can be output to the optical SW 50 regardless of the wavelength of the optical signal. Furthermore, the transmission / reception separators 51-1 to 51-2 can transfer the optical signal transferred from the optical SW 50 to the wavelength multiplexer / demultiplexer 52-2 regardless of the wavelength of the optical signal.

[0030] The wavelength multiplexers / demultiplexers 52-1 and 52-2 multiplex or demultiplex the input optical signals. The wavelength multiplexers / demultiplexers 52-1 and 52-2 are, for example, AWGs (Arrayed Waveguide Gratings).

[0031] The optical node device 15 is composed of an optical SW 55, a plurality of transmission / reception separators 56-1 to 56-2, and a plurality of wavelength multiplexers / demultiplexers 57-1 to 57-2. In the first embodiment, the optical node device 15 differs from the conventional configuration in that it uses a transmission / reception separator that does not have wavelength dependency, instead of a transmission / reception separator that separates optical signals by wavelength as used in the conventional technology. An example of a transmission / reception separator that does not have wavelength dependency is a circulator.

[0032] The optical SW55 is an optical switch having P (P is an integer equal to or greater than 2) ports 7 and Q (Q is an integer equal to or greater than 2) ports 8. In this embodiment, the numbers P and Q are described as 5. An optical signal input to a port of the optical SW55 is output from another port. For example, an optical signal input to port 7 of the optical SW55 is output from port 8. The connection relationship between the ports 7 and 8 of the optical SW55 is set under the control of the control unit 40-2.

[0033] The subscriber device 30-1 is connected to the port 7-2 of the optical SW 55 via an optical transmission line, the subscriber device 30-2 is connected to the port 7-3 of the optical SW 55 via an optical transmission line, and the subscriber device 30-3 is connected to the ports 7-4 and 7-5 of the optical SW 55 via optical transmission lines.

[0034] A control unit 40-2 is connected to port 8-1 of the optical SW55 via an optical transmission line, a transmit / receive separation unit 56-1 is connected to port 8-2 of the optical SW55 via an optical transmission line, a wavelength multiplexer / demultiplexer 57-2 is connected to port 8-3 of the optical SW55 via an optical transmission line, a transmit / receive separation unit 56-2 is connected to port 8-4 of the optical SW55 via an optical transmission line, and a wavelength multiplexer / demultiplexer 57-1 is connected to port 8-5 of the optical SW55 via an optical transmission line.

[0035] The transmission / reception separators 56-1 to 56-2 are, for example, circulators. The transmission / reception separators 56-1 to 56-2 have at least three or more ports. In the following description, it is assumed that the transmission / reception separators 56-1 to 56-2 have three ports. A first port 58-1 of the transmission / reception separator 56-1 is connected to a port 8 (port 8-2 in FIG. 1) of the optical SW 55. A second port 58-2 of the transmission / reception separator 56-1 is connected to a wavelength multiplexer / demultiplexer 57-1. A third port 58-3 of the transmission / reception separator 56-1 is connected to a wavelength multiplexer / demultiplexer 57-2. An optical signal input to the first port 58-1 is output from the second port 58-2. An optical signal input to the second port 58-2 is output from the third port 58-3. An optical signal input to the third port 58-3 is output from the first port 58-1.

[0036] Similarly, a first port 59-1 of the transmission / reception separator 56-2 is connected to port 8 (port 8-4 in FIG. 1) of the optical SW 55. A second port 59-2 of the transmission / reception separator 56-2 is connected to the wavelength multiplexer / demultiplexer 57-1. A third port 59-3 of the transmission / reception separator 56-2 is connected to the wavelength multiplexer / demultiplexer 57-2. An optical signal input to the first port 59-1 is output from the second port 59-2. An optical signal input to the second port 59-2 is output from the third port 59-3. An optical signal input to the third port 59-3 is output from the first port 59-1.

[0037] In this way, the transmission / reception separators 56-1 to 56-2 have directionality and port selectivity but are not wavelength-dependent. Therefore, the optical signal output by the subscriber device 30 can be output to the optical SW 55 regardless of the wavelength of the optical signal. Furthermore, the transmission / reception separators 56-1 to 56-2 can transfer the optical signal transferred from the optical SW 55 to the wavelength multiplexer / demultiplexer 57-2 regardless of the wavelength of the optical signal.

[0038] The subscriber devices 20 and 30 each include a wavelength-tunable optical transmitter / receiver as an optical transceiver. Therefore, the subscriber devices 20 and 30 can communicate at any wavelength. The wavelengths used by the subscriber devices 20 and 30 for communication are assigned by the control unit 40. For example, the wavelength used by the subscriber device 20 for communication is assigned by the control unit 40-1, and the wavelength used by the subscriber device 30 for communication is assigned by the control unit 40-2. The optical transceiver may be an optical transceiver with an AMCC (Auxiliary Management and Control Channel) function. In this case, the wavelengths used by the subscriber devices 20 and 30 are controlled via a control signal superimposed by the AMCC. The subscriber devices 20 and 30 are, for example, ONUs (Optical Network Units) installed in subscriber homes.

[0039] The control units 40-1 and 40-2 at least control the subscriber devices 20 and 30 and the optical switches 50 and 55. Here, the control of the subscriber devices 20 and 30 includes, for example, allocating emission wavelengths to the subscriber devices 20 and 30, issuing optical stop commands, and issuing wavelength change commands. The control of the optical switches 50 and 55 includes, for example, setting connections between the ports of the optical switches 50 and 55 and setting optical paths. The control units 40-1 and 40-2 perform similar processes except for the objects they control, so the control unit 40-1 will be taken as an example for explanation.

[0040] The control unit 40-1 includes an optical SW control unit 41-1 and a subscriber device management control unit 42-1. The optical SW control unit 41-1 controls the connection between the ports of the optical SW 50. Specifically, the optical SW control unit 41-1 controls the connection between the ports of the optical SW 50 so that an optical signal transmitted from the subscriber device 20 is forwarded to a destination subscriber device (e.g., the subscriber device 30-1). Controlling the connection between the ports means setting a path so that a certain port is connected to another port. Furthermore, the optical SW control unit 41-1 controls the connection between the ports of the optical SW 50 so that an optical signal addressed to the subscriber device 20 is forwarded to the subscriber device 20.

[0041] The subscriber device management and control unit 42-1 assigns wavelengths to each subscriber device 20. When the subscriber device management and control unit 42-1 assigns wavelengths to each subscriber device 20, the optical SW control unit 41-1 sets a route between the ports of the optical SW 50 so that the subscriber device 20 to which the wavelength is to be assigned is connected to the subscriber device management and control unit 42-1.

[0042] The subscriber device management control unit 42-1 stores a management table. The management table includes information for identifying the subscriber device 20, information on the wavelength assigned to the subscriber device 20, and information on the optical SW 50 to which the subscriber device 20 is connected (e.g., information on the port to which the subscriber device 20 is connected, etc.). Each control unit 40 is composed of one or more processors. Each functional unit of each control unit 40 is realized by mounting each control unit 40 on one server.

[0043] With the configuration shown in FIG. 1, it becomes possible to assign the same wavelength for the transmission wavelength and the reception wavelength to the subscriber devices 20 and 30 connected to the optical node devices 10 and 15, as shown in FIG. 2. FIG. 2 is a diagram showing an example of wavelength allocation in the first embodiment. The trapezoids shown in FIG. 2 show an image of the transmission band of each wavelength ch of the wavelength multiplexer / demultiplexer 52 and 57. Wavelengths that pass through the same trapezoid are the same wavelength ch. This also applies to FIG. 2 and subsequent figures. The example of transmission and reception in FIG. 2 shows a state seen from the subscriber device 20 accommodated in the optical node device 10. As shown in FIG. 2, the subscriber device management control unit 42-1 can assign, for example, the wavelength λ1 to the subscriber device 20-1 as the wavelength to be used for the transmission wavelength and the reception wavelength, and the wavelength λ2 to the subscriber device 20-2 as the wavelength to be used for the transmission wavelength and the reception wavelength.

[0044] Alternatively, the subscriber device management control unit 42 may assign wavelengths that transmit the same wavelength channel in the wavelength multiplexers / demultiplexers 52 and 57. For example, as shown in Fig. 3, the wavelengths for transmission and reception may be shifted by Δλ' in accordance with the transmission characteristics of the wavelength multiplexers / demultiplexers 52 and 57. Fig. 3 is a diagram showing another example of wavelength allocation in the first embodiment. The example of transmission and reception in Fig. 3 shows the state seen from the subscriber device 20 accommodated in the optical node device 10.

[0045] Fig. 4 is a sequence diagram for explaining the flow of processing in the optical communication system 1 in the first embodiment. At the start of the processing in Fig. 2, the connection relationship between the ports of the optical SW 30 is set as shown in Fig. 1. Fig. 2 illustrates the processing of the subscriber device 20-1 as the subscriber device 20 and the subscriber device 30-1 as the subscriber device 30, but the processing of the subscriber devices 20-2 and 20-3 and the subscriber devices 30-2 and 30-3 will also be explained.

[0046] The subscriber device 20-1 transmits an optical signal with a wavelength assigned by the control unit 40-1 (step S101). For example, the subscriber device management control unit 42-1 of the control unit 40-1 assigns the same wavelength (e.g., wavelength λ1) for transmission and reception to the subscriber device 20-1. Similarly, the subscriber device management control unit 42-1 of the control unit 40-1 assigns the same wavelength (e.g., wavelength λ2) for transmission and reception to the subscriber device 20-2, and assigns the same wavelength (e.g., wavelength λ3) for transmission and reception to the subscriber device 20-3.

[0047] For example, the subscriber device management and control unit 42-2 of the control unit 40-2 assigns the same wavelength (e.g., wavelength λ1) for transmission and reception to the subscriber device 30-1. Similarly, the subscriber device management and control unit 42-2 of the control unit 40-2 assigns the same wavelength (e.g., wavelength λ2) for transmission and reception to the subscriber device 30-2, and assigns the same wavelength (e.g., wavelength λ3) for transmission and reception to the subscriber device 30-3.

[0048] The subscriber device 20-1 is connected to port 5-2 of the optical SW 50 via an optical transmission line. An optical signal transmitted from the subscriber device 20-1 is input to port 5-2 of the optical SW 50 via the optical transmission line. Port 5-2 of the optical SW 50 is connected to port 6-2. Therefore, the optical signal input to port 5-2 of the optical SW 50 is output from port 6-2.

[0049] The first port 53-1 of the transmission / reception separator 51-1 is connected to the port 6-2 of the optical SW50. Therefore, the optical signal output from the port 6-2 of the optical SW50 is input to the first port 53-1 of the transmission / reception separator 51-1. The optical signal input to the first port 53-1 of the transmission / reception separator 51-1 is output from the second port 53-2 (step S102). The optical signal output from the second port 53-2 of the transmission / reception separator 51-1 is input to the wavelength multiplexer / demultiplexer 52-2.

[0050] Like the subscriber device 20-1, the subscriber devices 20-2 and 20-3 also transmit optical signals of wavelengths assigned by the control unit 40-1. The subscriber device 20-2 is connected to port 5-3 of the optical SW 50 via an optical transmission line. The optical signal transmitted from the subscriber device 20-2 is input to port 5-3 of the optical SW 50 via the optical transmission line. The port 5-3 of the optical SW 50 is connected to port 6-4. Therefore, the optical signal input to port 5-3 of the optical SW 50 is output from port 6-4.

[0051] A first port 54-1 of the transmission / reception separator 51-2 is connected to the port 6-4 of the optical SW50. Therefore, the optical signal output from the port 6-4 of the optical SW50 is input to the first port 54-1 of the transmission / reception separator 51-2. The optical signal input to the first port 54-1 of the transmission / reception separator 51-2 is output from the second port 54-2. The optical signal output from the second port 54-2 of the transmission / reception separator 51-2 is input to the wavelength multiplexer / demultiplexer 52-2.

[0052] The subscriber device 20-3 is connected to ports 5-4 and 5-5 of the optical SW 50 via an optical transmission line. The subscriber device 20-3 is connected to the optical SW 50 via a two-core optical transmission line. Here, it is assumed that the transmitting port of the subscriber device 20-3 is connected to port 5-4 of the optical SW 50, and the receiving port of the subscriber device 20-3 is connected to port 5-5 of the optical SW 50. An optical signal transmitted from the subscriber device 20-3 is input to port 5-4 of the optical SW 50 via the optical transmission line. Port 5-4 of the optical SW 50 is connected to port 6-3. Therefore, the optical signal input to port 5-4 of the optical SW 50 is output from port 6-3.

[0053] A wavelength multiplexer / demultiplexer 52-2 is connected to port 6-3 of the optical SW 50. Therefore, the optical signal output from port 6-3 of the optical SW 50 is input to the wavelength multiplexer / demultiplexer 52-2. In this manner, optical signals of different wavelengths transmitted from each subscriber device 20 are input to the wavelength multiplexer / demultiplexer 52-2. The wavelength multiplexer / demultiplexer 52-2 multiplexes the input optical signals of different wavelengths (step S103).

[0054] The optical signal multiplexed by the wavelength multiplexer / demultiplexer 52-2 is transmitted to the optical node device 15 via the optical transmission line (step S104). The wavelength multiplexer / demultiplexer 52-2 is connected to the wavelength multiplexer / demultiplexer 57-2 of the optical node device 15 via the optical transmission line. Therefore, the optical signal multiplexed by the wavelength multiplexer / demultiplexer 52-2 is input to the wavelength multiplexer / demultiplexer 57-2. The wavelength multiplexer / demultiplexer 57-2 demultiplexes the input optical signal (step S105). The optical signal demultiplexed by the wavelength multiplexer / demultiplexer 57-2 is output from a port corresponding to the wavelength. Here, it is assumed that the optical signal demultiplexed by the wavelength multiplexer / demultiplexer 57-2 is input to the third port 58-3 of the transmission / reception separation unit 56-1, the port 8-3 of the optical SW 55, and the third port 59-3 of the transmission / reception separation unit 56-2.

[0055] The optical signal input to the third port 58-3 of the transmission / reception separator 56-1 is output from the first port 58-1 of the transmission / reception separator 56-1 (step S106). The first port 58-1 of the transmission / reception separator 56-1 is connected to the port 8-2 of the optical SW 55. Therefore, the optical signal output from the first port 58-1 of the transmission / reception separator 56-1 is input to the port 8-2 of the optical SW 55. The port 8-2 of the optical SW 55 is connected to the port 7-2. Therefore, the optical signal input to the port 8-2 of the optical SW 55 is output from the port 7-2 of the optical SW 55. The subscriber device 30-1 is connected to the port 7-2 of the optical SW 55. Therefore, the optical signal output from the port 7-2 of the optical SW 55 is input to the subscriber device 30-1 via the optical transmission path. As a result, the subscriber device 30-1 receives the optical signal with wavelength λ1 (step S107).

[0056] Port 8-3 of the optical SW55 is connected to port 7-4. Therefore, an optical signal input to port 8-3 of the optical SW55 is output from port 7-4. Port 7-4 of the optical SW55 is connected to subscriber device 30-3. Therefore, an optical signal output from port 7-4 of the optical SW55 is input to subscriber device 30-3 via the optical transmission path. As a result, subscriber device 30-3 receives an optical signal with wavelength λ3.

[0057] The optical signal input to the third port 59-3 of the transmission / reception separator 56-2 is output from the first port 59-1 of the transmission / reception separator 56-2. The first port 59-1 of the transmission / reception separator 56-2 is connected to the port 8-4 of the optical SW 55. Therefore, the optical signal output from the first port 59-1 of the transmission / reception separator 56-2 is input to the port 8-4 of the optical SW 55. The port 8-4 of the optical SW 55 is connected to the port 7-3. Therefore, the optical signal input to the port 8-4 of the optical SW 55 is output from the port 7-3 of the optical SW 55. The port 7-3 of the optical SW 55 is connected to the subscriber device 30-2. Therefore, the optical signal output from the port 7-3 of the optical SW 55 is input to the subscriber device 30-2 via the optical transmission line. As a result, the subscriber device 30-2 receives the optical signal with wavelength λ2.

[0058] According to the optical communication system 1 configured as above, it becomes possible to easily perform wavelength management in an optical communication system in which a configuration in which a subscriber device uses the same wavelength for transmission and reception and a configuration in which a subscriber device uses different wavelengths for transmission and reception are mixed. Specifically, in the optical communication system 1, by using a transmission / reception separator that does not have wavelength dependency, it becomes possible to manage the wavelengths of transmission and reception by the same method, regardless of the connection form (one core or two cores) of the optical access section, and it is possible to suppress the complexity of wavelength management. As a result, it becomes possible to easily perform wavelength management in an optical communication system in which a subscriber device uses the same wavelength for transmission and reception and a configuration in which a subscriber device uses different wavelengths for transmission and reception are mixed.

[0059] Furthermore, in the optical communication system 1, it becomes possible to perform communications using all wavelength channels in the wavelength tunable range of the wavelength tunable transceivers mounted in the subscriber devices 20 and 30. As a result, it becomes possible to increase the number of users that can be accommodated in the optical node devices 10 and 15.

[0060] Second embodiment In the second embodiment, a configuration will be described in which the relationship between the transmission and reception wavelengths in a subscriber unit is set to Δλ / 2. The system configuration of the second embodiment is similar to that of the first embodiment.

[0061] Fig. 5 is a diagram showing an example of wavelength allocation in the second embodiment. The example of transmission and reception in Fig. 5 shows a state seen from the subscriber device 20 accommodated in the optical node device 10. As shown in Fig. 5, the subscriber device management control unit 42-1 arranges the wavelengths so that the relationship between the transmission and reception wavelengths in the subscriber device 20-1 is Δλ / 2, and further sets the transmission wavelength band of the wavelength multiplexer / demultiplexer 52 to Δλ×N (N=2, 3, 4...n), and assigns a wavelength that matches the transmission wavelength of the wavelength multiplexer / demultiplexer 52 to the subscriber device 20.

[0062] Similarly, the subscriber device management control unit 42-2 is configured so that the relationship between the transmission and reception wavelengths in the subscriber device 30-1 is Δλ / 2, and further, the transmission wavelength band of the wavelength multiplexer / demultiplexer 57 is set to Δλ×N (N=2, 3, 4, . . . n), and a wavelength that matches the transmission wavelength of the wavelength multiplexer / demultiplexer 57 is assigned to the subscriber device 20.

[0063] According to the optical communication system 1 in the second embodiment configured as above, it is possible to obtain the same effects as those of the first embodiment.

[0064] (Third embodiment) In the third embodiment, a configuration in which the transmission and reception separation unit has a different configuration will be described. Fig. 6 is a diagram showing the configuration of an optical communication system 1a in the third embodiment. The optical communication system 1a includes a plurality of optical node devices 10a, 15a, a plurality of subscriber devices 20-1 to 20-3, a plurality of subscriber devices 30-1 to 30-3, and a plurality of control units 40-1 to 40-2. The optical communication system 1a differs in configuration from the optical communication system 1 in that the optical communication system 1a includes optical node devices 10a, 15a instead of the optical node devices 10, 15.

[0065] The control unit 40 assigns to the subscriber devices 20 and 30 wavelengths with a wavelength shift of Δλ' between transmission and reception as in the first embodiment (for example, the wavelength allocation shown in FIG. 3).

[0066] The optical node device 10a is composed of an optical SW 50, a plurality of transmission and reception separators 61-1 to 61-2, and a plurality of wavelength multiplexers and demultiplexers 52-1 to 52-2. The optical node device 15a is composed of an optical SW 50, a plurality of transmission and reception separators 65-1 to 65-2, and a plurality of wavelength multiplexers and demultiplexers 57-1 to 57-2. The optical node devices 10a and 15a are equipped with the configuration shown in Fig. 7 as the transmission and reception separators 61-1 to 61-2 or the transmission and reception separators 65-1 to 65-2, instead of circulators. Fig. 7 is a diagram showing the configuration of the transmission and reception separators 61 and 65 in the third embodiment.

[0067] The transmission / reception separation units 61, 65 are composed of a first optical filter 611, a second optical filter 612, an optical coupler 613, and an optical non-reflective terminator 614. The first optical filter 611 and the second optical filter 612 have transmission characteristics as shown in FIG. 8, and are configured to transmit the wavelengths of the transmission and reception signals, respectively. Here, the transmission characteristics differ between the optical filters according to the difference width Δλ' between the transmission and reception wavelengths. Examples of means for realizing optical filters having such transmission characteristics include an etalon filter and a Mach-Zehnder interferometer. FIG. 8 is a diagram showing an example of the transmission characteristics of the first optical filter 611 and the second optical filter 612.

[0068] The optical coupler 613 has a configuration in which one port of a 2×2 coupler is terminated by an optical non-reflection terminator 614 to block the input and output of light. The optical coupler 613 multiplexes or demultiplexes an input optical signal. For example, the optical coupler 613 demultiplexes an optical signal input via an optical transmission line 621 and outputs the demultiplexed signal to optical transmission lines 622 and 623. The optical coupler 613 multiplexes an optical signal input via an optical transmission line 622 and an optical signal input via an optical transmission line 623 and outputs the multiplexed signal to the optical transmission line 621. The optical signal flowing through the optical transmission line to which the optical non-reflection terminator 614 is connected is terminated by the optical non-reflection terminator 614.

[0069] When the transmit / receive separation unit shown in Figure 7 is provided in the optical node device 10a, for example, the optical transmission path 621 in the transmit / receive separation unit 61 is connected to port 6 of the optical SW50, the first optical filter 611 in the transmit / receive separation unit 61 is connected to the wavelength multiplexer / demultiplexer 52-2, and the second optical filter 612 in the transmit / receive separation unit 61 is connected to the wavelength multiplexer / demultiplexer 52-1.

[0070] When the transmit / receive separation unit shown in FIG. 7 is provided in the optical node device 15a, for example, the optical transmission path 621 in the transmit / receive separation unit 65 is connected to port 8 of the optical SW 50, the first optical filter 611 in the transmit / receive separation unit 65 is connected to the wavelength multiplexer / demultiplexer 57-2, and the second optical filter 612 in the transmit / receive separation unit 65 is connected to the wavelength multiplexer / demultiplexer 57-1.

[0071] According to the optical communication system 1a configured as above, by providing a transmission / reception separator other than the transmission / reception separator that does not have wavelength dependency (for example, the transmission / reception separator shown in FIG. 7), it is possible to obtain the same effect as the first embodiment.

[0072] (Fourth embodiment) In the fourth embodiment, a configuration will be described in which a transmission / reception separator is provided between a subscriber device and an optical SW. 9 is a diagram showing the configuration of an optical communication system 1b in the fourth embodiment. The optical communication system 1b includes multiple optical node devices 10b and 15b, multiple subscriber devices 20-1 to 20-3, multiple subscriber devices 30-1 to 30-3, and multiple control units 40-1 to 40-2. The optical communication system 1b differs in configuration from the optical communication system 1 in that the optical communication system 1b includes optical node devices 10b and 15b instead of the optical node devices 10 and 15.

[0073] The optical node device 10b is composed of an optical SW50, a plurality of transmission / reception separators 51-1 to 51-2, and a plurality of wavelength multiplexers / demultiplexers 52-1 to 52-2. In the optical node device 10b, a plurality of transmission / reception separators 51-1 to 51-2 are provided between the subscriber device 20 and the optical SW50. More specifically, the transmission / reception separator 51-1 is connected to the subscriber device 20-1, which was connected to the optical SW50 by a single-core optical transmission line, and the transmission / reception separator 51-2 is connected to the subscriber device 20-2. This makes it possible to demultiplex (convert to two-core) an optical signal transmitted from the subscriber device 20 connected to the transmission / reception separator 51 and output it to the optical SW50.

[0074] The optical node device 15b is composed of an optical SW 50, a plurality of transmission / reception separators 56-1 to 56-2, and a plurality of wavelength multiplexers / demultiplexers 52-1 to 52-2. In the optical node device 15b, a plurality of transmission / reception separators 56-1 to 56-2 are provided between the subscriber device 30 and the optical SW 55. More specifically, the transmission / reception separator 56-1 is connected to the subscriber device 30-1, which was connected to the optical SW 55 by a single-core optical transmission line, and the transmission / reception separator 56-2 is connected to the subscriber device 30-2. This makes it possible to demultiplex (convert to two-core) an optical signal transmitted from the subscriber device 30 connected to the transmission / reception separator 56 and output it to the optical SW 55.

[0075] In the configuration of the first embodiment, it was necessary to select a connection configuration between the optical SW and the wavelength multiplexer / demultiplexer according to the connection configuration of the optical access section. In contrast, according to the optical communication system 1b configured as described above, it is possible to flexibly configure the connection of the optical transmission line between the optical SW and the wavelength multiplexer / demultiplexer regardless of whether one-core bidirectional communication or two-core communication is used, i.e., regardless of the connection form of the optical access section.

[0076] In addition, in FIG. 9, a circulator is used as an example of the transmission / reception separator, but a transmission / reception separator shown in FIG. 11 may be used.

[0077] Fifth embodiment In the fifth embodiment, a configuration in which a transmission / reception separator is provided in a subscriber device will be described. 10 is a diagram showing the configuration of an optical communication system 1c in the fifth embodiment. The optical communication system 1c includes multiple optical node devices 10c and 15c, multiple subscriber devices 20c-1 to 20c-3, multiple subscriber devices 30c-1 to 30c-3, and multiple control units 40-1 to 40-2. The optical communication system 1c differs in configuration from the optical communication system 1 in that it includes optical node devices 10c and 15c instead of the optical node devices 10 and 15, and in that it includes subscriber devices 20c and 30c instead of the subscriber devices 20 and 30.

[0078] The optical node device 10c is composed of an optical SW 50 and one wavelength multiplexer / demultiplexer 52. As described above, in the optical node device 10c, no transmission / reception separation unit is provided between the optical SW 50 and the wavelength multiplexer / demultiplexer 52. Ports 6-2 to 6-4 of the optical SW 50 are connected to the wavelength multiplexer / demultiplexer 52 via optical transmission paths. Therefore, the optical SW control unit 41-1 controls the connection relationship between the ports of the optical SW 50 according to the wavelength of the optical signal transmitted by the subscriber device 20.

[0079] The optical node device 15c is configured with an optical SW 55 and one wavelength multiplexer / demultiplexer 57. As described above, in the optical node device 15c, no transmission / reception separation unit is provided between the optical SW 55 and the wavelength multiplexer / demultiplexer 57. Ports 8-2 to 8-4 of the optical SW 55 are connected to the wavelength multiplexer / demultiplexer 57 via optical transmission paths. Therefore, the optical SW control unit 41-2 controls the connection relationship between the ports of the optical SW 55 according to the wavelength of the optical signal transmitted by the subscriber device 30.

[0080] 11 is a diagram showing an example of the configuration of the subscriber devices 20c and 30c in the fifth embodiment. The subscriber devices 20c and 30c each include a transmitter 21, a transmission / reception separator 22, and a receiver 23. The transmitter 21 transmits an optical signal having a wavelength assigned by the control unit 40 via the transmission / reception separator 22.

[0081] The transmission / reception separator 22 is, for example, a circulator, as in the first embodiment. The transmission / reception separator 22 has a first port 24-1, a second port 24-2, and a third port 24-3. The first port 24-1 of the transmission / reception separator 22 is connected to the transmitter 21. The second port 24-2 of the transmission / reception separator 22 is connected to an optical transmission path connected to the optical node devices 10c and 15c. The third port 24-3 of the transmission / reception separator 22 is connected to the receiver 23. An optical signal input to the first port 24-1 is output from the second port 24-2. An optical signal input to the second port 132 is output from the third port 24-3.

[0082] The receiver 23 receives the optical signal transferred from the transmission / reception separator 22. For example, the receiver 23 is a photo diode (PD) or the like. The transmitter 21 and the receiver 23 are wavelength-tunable optical transceivers. The control unit 40-1 assigns the same wavelength for transmission and reception, or different wavelengths for transmission and reception, to the subscriber device 20c. Similarly, the control unit 40-2 assigns the same wavelength for transmission and reception, or different wavelengths for transmission and reception, to the subscriber device 30c.

[0083] According to the optical communication system 1c configured as above, even if there are subscriber devices to which the same wavelength is assigned for transmission and reception and subscriber devices to which different wavelengths are assigned for transmission and reception, each of the subscriber devices 20c, 30c has a transmission / reception separator (e.g., a circulator) that does not have wavelength dependency, so that the control unit 40 does not need to change the policy of wavelength management for transmission and reception according to the connection form of the optical access section. Therefore, it becomes possible to easily perform wavelength management.

[0084] Some of the functional units of the optical node devices 10, 10a, 15, 15a and the control unit 40 in the above-mentioned embodiments may be realized by a computer. In this case, a program for realizing this function may be recorded in a computer-readable recording medium, and the program recorded in the recording medium may be read into a computer system and executed to realize the function. Note that the "computer system" here includes hardware such as an OS and peripheral devices.

[0085] In addition, the term "computer-readable recording medium" refers to portable media such as flexible disks, optical magnetic disks, ROMs, and CD-ROMs, and storage devices such as hard disks built into computer systems. Furthermore, the term "computer-readable recording medium" may also include those that dynamically hold a program for a short period of time, such as a communication line when transmitting a program via a network such as the Internet or a communication line such as a telephone line, and those that hold a program for a certain period of time, such as a volatile memory inside a computer system that serves as a server or client in such a case. Furthermore, the above program may be one that realizes part of the above-mentioned functions, or may be one that can realize the above-mentioned functions in combination with a program already recorded in the computer system, or may be one that is realized using a programmable logic device such as an FPGA.

[0086] Although an embodiment of the present invention has been described in detail above with reference to the drawings, the specific configuration is not limited to this embodiment, and designs that do not deviate from the gist of the present invention are also included. [Industrial Applicability]

[0087] The present invention can be applied to an optical communication system in which subscriber devices performing bidirectional communication over one fiber and subscriber devices performing bidirectional communication over two fibers are mixed in an optical access section of the optical communication system. [Explanation of symbols]

[0088] 10, 10a, 10b, 10c, 15, 15a, 15b, 15c…optical device, 20, 20c, 20-1~20-3, 20c-1~20c-3, 30, 30c, 30-1~30-3, 30c-1~30c-3…subscriber device, 21…transmitter, 23…receiver, 40, 40-1~40-2…control unit, 41, 41-1~41-2…optical SW control unit, 42, 42-1~42-2…subscriber device management control unit, 22, 51, 51-1~51-2, 61-1~61-2, 65-1~65-2…transmitter and receiver separation unit, 52, 52-1~52-2, 57, 57-1~57-2…Wavelength combiner / demultiplexer

Claims

1. An optical node device to which a first subscriber device and a second subscriber device are connected in an optical communication system in which a first subscriber device and a second subscriber device are connected in two cores using different wavelengths for transmission and reception are mixed, the optical node device being connected to the first subscriber device and the second subscriber device, a transmission / reception separation unit for transferring an optical signal transmitted from the first subscriber device and an optical signal addressed to the first subscriber device without causing interference therebetween; an optical switch in which a connection relationship between ports is controlled so that an optical signal transmitted from the first subscriber device or an optical signal destined for the first subscriber device passes through the transmission / reception separation unit, and an optical signal transmitted from the second subscriber device or an optical signal destined for the second subscriber device does not pass through the transmission / reception separation unit, and which outputs an optical signal input from one optical transmission path from another optical transmission path; The optical node device includes:

2. the transmission / reception separator is a circulator, the circulator has a first port, a second port, and a third port; the first port is connected to the optical switch; the second port is connected to a first wavelength multiplexer / demultiplexer that multiplexes an optical signal transmitted from the first subscriber device or an optical signal transmitted from the second subscriber device; the third port is connected to a second wavelength division multiplexer that demultiplexes an optical signal addressed to the first subscriber device or the second subscriber device; the circulator outputs an optical signal input to the first port to the first wavelength multiplexer / demultiplexer connected to the second port, and outputs an optical signal input to the third port to the optical switch connected to the first port. The optical node device according to claim 1 .

3. the transmission / reception separator is a circulator, the circulator has a first port, a second port, and a third port; the first port is connected to the first subscriber device; the second port and the third port are connected to the optical switch; the circulator outputs an optical signal input to the first port to the optical switch connected to the second port, and outputs an optical signal input to the third port to the first subscriber device connected to the first port. The optical node device according to claim 1 .

4. the transmission / reception separation unit is composed of an optical coupler, a first optical filter used during transmission to transmit a specific wavelength, and a second optical filter used during reception to transmit a specific wavelength, the first optical filter and the second optical filter have transmission characteristics in accordance with a wavelength shift width between transmission and reception; The optical node device according to claim 1 .

5. the transmission / reception separator is provided between the first subscriber device and the optical switch; The optical node device according to claim 1 .

6. The transmission / reception separation unit is provided between the optical switch and the first wavelength multiplexer / demultiplexer or the second wavelength multiplexer / demultiplexer. The optical node device according to claim 2 .

7. An optical communication system comprising a first subscriber device connected with one core using different wavelengths for transmission and reception, a second subscriber device connected with two cores using the same wavelength for transmission and reception, and an optical node device to which the first subscriber device and the second subscriber device are connected, The first subscriber device and the second subscriber device Transmitting an optical signal; The optical node device includes: a transmission / reception separator for transferring the optical signal transmitted from the first subscriber device and an optical signal addressed to the first subscriber device without causing interference therebetween; an optical switch in which a connection relationship between ports is controlled so that the optical signal transmitted from the first subscriber device or the optical signal destined for the first subscriber device passes through the transmission / reception separator, and the optical signal transmitted from the second subscriber device or the optical signal destined for the second subscriber device does not pass through the transmission / reception separator, and which outputs an optical signal input from one optical transmission path from another optical transmission path; Equipped with an optical communication system.

8. A transfer method performed by an optical node device to which a first subscriber device and a second subscriber device are connected in an optical communication system in which a first subscriber device and a second subscriber device are connected in a single core using different wavelengths for transmission and reception and a second subscriber device and a second subscriber device are connected in a single core using the same wavelength for transmission and reception, a transmission / reception separation unit that transfers an optical signal transmitted from the first subscriber device and an optical signal addressed to the first subscriber device without causing interference therebetween; a connection relationship between ports is controlled so that an optical signal transmitted from the first subscriber device or an optical signal destined for the first subscriber device passes through the transmission / reception separation unit, and an optical signal transmitted from the second subscriber device or an optical signal destined for the second subscriber device does not pass through the transmission / reception separation unit, and an optical signal input from one optical transmission path is output from another optical transmission path. Transfer method.

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