Optical node device and connection method

Abstract

Provided is an optical node device comprising: a plurality of ports to which one or more communication devices that perform one-core bidirectional transmission or two-core transmission are connected; and one or more transceivers that are connected to at least one port via at least one first wavelength multiplexing / demultiplexing unit that multiplexes or demultiplexes an optical signal that has been inputted, and transmit and receive control signal light to and from the one or more communication devices. The one or more transceivers comprise: one or more receivers that receive uplink control signal light transmitted from the one or more communication devices and output the uplink control signal light to a control device; one or more transmitters that transmit downlink control signal light addressed to one or more of the communication devices; and one or more second wavelength multiplexing / demultiplexing units that output, to one or more receivers, uplink control signal light input via at least one connected first wavelength multiplexing / demultiplexing unit, and output, to at least one connected first wavelength multiplexing / demultiplexing unit, downlink control signal light transmitted from one or more of the transmitters.　

Description

Optical node device and connection method

[0001] The present invention relates to an optical node device and a connection method.

[0002] In conventional optical communication systems, a communication device needs to open an optical path to connect with a communication device that will be the communication partner in order to communicate. Figures 7 and 8 are diagrams for explaining a method of opening an optical path in a conventional optical communication system S. As shown in Figure 7, the conventional optical communication system S includes a plurality of communication devices 200-1 to 200-3, a plurality of communication devices 300-1 to 300-3, a plurality of control units 400-1 to 400-2, and a plurality of optical node devices 500-1 to 500-2.

[0003] It is assumed that the communication device 200-1 is not connected to the optical node device 500-1, the communication devices 200-2 to 200-3 are connected to the optical node device 500-1 via optical transmission paths, and the communication devices 300-1 to 300-3 are connected to the optical node device 500-2 via optical transmission paths. The optical node device 500-1 and the optical node device 500-2 are connected via an optical communication NW 600 configured by an optical transmission path. The control unit 400-1 manages the communication device 200 and controls the operation of the optical node device 500-1. The control unit 400-2 manages the communication device 300 and controls the operation of the optical node device 500-2.

[0004] The optical node devices 500-1 to 500-2 are connected to multiple optical transmission paths, and output optical signals input from each port to ports that are set as connection ports for the corresponding ports. The connection relationships between ports can be changed or set arbitrarily. The optical node devices 500-1 to 500-2 can also multiplex optical signals input from multiple communication devices 200, 300 to different ports, and output the multiplexed signal light to the optical transmission path from another port.

[0005] When a user newly connects a communication device 200-1 to the optical node device 500-1, at the time of initial connection of the newly connected communication device (hereinafter referred to as the "newly connected device"), the new connected device and the control unit 400 exchange information necessary for registering and authenticating the new connected device, and the subscriber device management control unit 420 can instruct the new connected device on the emission wavelength to be used for transmission and reception. The control unit 400 and the communication devices 200 and 300 may exchange control signals using the same optical transmission path as the main signal light. For example, a configuration in which control signal light is transmitted and received using a wavelength different from that of the main signal light, or a configuration in which a low-speed control signal called an Auxiliary Management and Control Channel (AMCC) is superimposed, can be used. The AMCC signal includes status information indicating, for example, the transmission and reception wavelengths, transmission light intensity, and temperature of the optical transceiver provided in the communication device.

[0006] When the registration and authentication of the new connection device and wavelength setting are completed, the optical node control unit 410 changes the setting of the port connection of the optical node device 500-1 so that the optical signal transmitted from the communication device 200-1, which is the new connection device, is forwarded to the communication device 300 (for example, communication device 300-1) that is the communication partner, as shown in Figure 8. Similarly, the control unit 400-2 changes the setting of the port connection of the optical node device 500-2 so that the optical signal transmitted from the communication device 200-1 is forwarded to the communication device 300 (for example, communication device 300-1) that is the communication partner. This makes it possible to open an optical path connecting the communication device 200-1 and the communication device 300-1, as shown in Figure 8.

[0007] International Publication No. 2020 / 036878

[0008] S. Kaneko, M. Yoshino, N. Shibata, R. Igarashi, J. Kani, and T. Yoshida, “Photonic Gateway accommodating all types of wavelength paths for digital-coherent and IM-DD user terminals in all-photonic metro-access converged networks”, J. Opt. Commun. and Net., vol.16, no.3, pp.304-316, March 2024, doi: http: / / doi.org / 10.1364 / JOCN.503093.

[0009] 9 has been proposed as a configuration for exchanging control signals between the communication devices 200, 300 and the control unit 400 (see, for example, Non-Patent Document 1). Fig. 9 shows, as an example, a configuration for exchanging control signals between the communication device 200 and the control unit 400. In the configuration shown in Fig. 9, control signal light is transmitted and received between the communication device 200 and the control unit 400 using a wavelength different from that of the main signal light, and the control signal light is wavelength-multiplexed with the main signal light in the section between the communication device 200 and the optical node device and transmitted through the same optical transmission path.

[0010] When a coherent transceiver is used as an optical transceiver for a communication device, it is generally necessary to use a two-core transmission network configuration in which the communication device 200 and the optical node device 500 are connected by two optical transmission paths and the upstream signal light and the downstream signal light are transmitted by different optical transmission paths. In this case, as shown in Fig. 9, the transmitting port of the communication device 200 and the port of the optical node device are connected by one optical transmission path, and the receiving port of the communication device 200 and the port of the optical node device are connected by one optical transmission path.

[0011] Coherent transceivers achieve high receiving sensitivity by interfering a strong local oscillator light with an input optical signal and extracting the beat component as a signal component. This optical transceiver configuration uses a portion of the output light from the light source for the transmitted optical signal as the local oscillator light, eliminating the need for a dedicated local oscillator light source and making the optical transceiver more economical. When using the above-mentioned coherent transceiver for single-fiber bidirectional transmission, the beat component between the upstream signal light and the local oscillator light, which returns to the optical transceiver due to reflections in the optical transmission path, becomes a large noise component, significantly degrading the reception characteristics of the downstream signal. Therefore, when using coherent transceivers, a two-fiber transmission network configuration is widely used.

[0012] In FIG. 9, a communication device 200-1 that performs two-core transmission has a wavelength λ １ The upstream control signal light and wavelength λ ２ The communication device 200-1 wavelength-multiplexes the main signal light of wavelength λ 1 at the receiving port side and transmits it. １ Downstream control signal light and wavelength λ ２ The optical node device 500 includes a wavelength multiplexing / demultiplexing unit 530 on the access port side to which each communication device 200 is connected, which multiplexes / demultiplexes the optical main signal and the optical control signal.

[0013] The wavelength multiplexed signal (upstream control signal light and main signal light) output from the transmission port of the communication device 200-1 that performs two-core transmission is separated by the wavelength multiplexing / demultiplexing unit 530. The separated upstream control signal light is then received by the receiver of the control transceiver 520. In addition, a wavelength λ 1 output from the transmitter of the same control transceiver 520 that receives the upstream control signal light is １ The downstream control signal light is divided into two by the wavelength multiplexer / demultiplexer 530 into two signals of wavelength λ ２ The optical signal is wavelength-multiplexed with the main signal light and sent out to the communication device 200-1.

[0014] On the other hand, one type of optical transceiver for communication devices is an optical transceiver for single-fiber bidirectional transmission, which transmits upstream and downstream signal light of different wavelengths over a single optical transmission line. When communication devices 200-2 and 200-3 that perform single-fiber bidirectional transmission and are equipped with this type of optical transceiver are connected to the optical node device 500, either the communication device 200 or the optical node device 500 that performs single-fiber bidirectional transmission will be unable to receive the control signal light.

[0015] 9, the communication device 200-2 is connected via an optical transmission path to a wavelength multiplexing / demultiplexing unit 530 to which a transmitter of a control transceiver 520 provided in the optical node device 500 is connected. In this case, the communication device 200-2 can receive downstream control signal light transmitted from the optical node device 500. On the other hand, the optical node device 500 cannot receive upstream control signal light transmitted from the communication device 200-2.

[0016] 9, for example, the communication device 200-3 is connected via an optical transmission path to a wavelength multiplexing / demultiplexing unit 530 to which a receiver of a control transceiver 520 provided in the optical node device 500 is connected. In this case, the optical node device 500 can receive upstream control signal light transmitted from the communication device 200-3. On the other hand, the communication device 200-3 cannot receive downstream control signal light transmitted from the optical node device 500. In other words, the conventional control signal light transmission / reception configuration shown in FIG. 9 has a problem in that the communication device 200 performing single-core bidirectional transmission cannot exchange control signals with the control unit 400.

[0017] In view of the above circumstances, an object of the present invention is to provide a technology that allows signals to be exchanged with a control unit regardless of the type of transmission method used by the communication device.

[0018] One aspect of the present invention is an optical node device provided between one or more communication devices that perform single-core bidirectional transmission or dual-core transmission and a control device that controls the one or more communication devices, the optical node device comprising: a plurality of ports to which the one or more communication devices are connected; and one or more transceivers connected to at least one port via at least one first wavelength multiplexing / demultiplexing unit that multiplexes or demultiplexes an input optical signal, and that transmit and receive control signal light to and from the one or more communication devices, the one or more transceivers comprising: one or more receivers that receive upstream control signal light transmitted from the one or more communication devices and output it to the control device; one or more transmitters that transmit downstream control signal light addressed to the one or more communication devices; and one or more second wavelength multiplexing / demultiplexing units that output the upstream control signal light input via the at least one first wavelength multiplexing / demultiplexing unit connected to the one or more first wavelength multiplexing / demultiplexing unit to the one or more receivers, and output the downstream control signal light transmitted from the one or more transmitters to the at least one first wavelength multiplexing / demultiplexing unit connected to the one or more first wavelength multiplexing / demultiplexing unit.

[0019] One aspect of the present invention is a connection method performed by an optical node device provided between one or more communication devices that perform single-core bidirectional transmission or dual-core transmission and a control device that controls the one or more communication devices, wherein one or more transceivers that are connected to at least one port out of a plurality of ports to which the one or more communication devices are connected via at least one first wavelength multiplexing / demultiplexing unit that multiplexes or demultiplexes an input optical signal and that transmit and receive control signal light to the one or more communication devices receive upstream control signal light transmitted from the one or more communication devices and output it to the control device, send downstream control signal light addressed to the one or more communication devices, receive the upstream control signal light input via at least one of the connected first wavelength multiplexing / demultiplexing units and output it to the control device, and output the sent downstream control signal light to at least one of the connected first wavelength multiplexing / demultiplexing units.

[0020] According to the present invention, signals can be exchanged with the control unit regardless of the type of transmission method used by the communication device.

[0021] FIG. 1 is a diagram illustrating an example of the configuration of an optical communication system in a first embodiment. FIG. 2 is a diagram for explaining how a first initial connection method performed by the optical communication system in the first embodiment is started. FIG. 3 is a sequence diagram illustrating the processing flow of the first initial connection method performed by the optical communication system in the first embodiment. FIG. 4 is a diagram for explaining how a second initial connection method performed by the optical communication system in the first embodiment is started. FIG. 5 is a sequence diagram illustrating the processing flow of the second initial connection method performed by the optical communication system in the first embodiment. FIG. 6 is a diagram illustrating an example of the configuration of an optical communication system in a second embodiment. FIG. 7 is a diagram for explaining a method of opening an optical path in a conventional optical communication system. FIG. 8 is a diagram for explaining a method of opening an optical path in a conventional optical communication system. FIG. 9 is a diagram for explaining problems in conventional optical communication systems.

[0022] Hereinafter, an embodiment of the present invention will be described with reference to the drawings.

[0023] First Embodiment Fig. 1 is a diagram showing an example of the configuration of an optical communication system 100 in a first embodiment. The optical communication system 100 includes an optical node device 10 and a control unit 20. One or more communication devices 30 are connected to the optical node device 10 via an optical transmission path L. The optical transmission path L is, for example, an optical fiber. In the example shown in Fig. 1, three communication devices 30-1 to 30-3 are connected to the optical node device 10 via the optical transmission path L, but the number of communication devices 30 may be one or more.

[0024] In the optical communication system 100, the communication device 30-1 is a device that performs two-core transmission, and the communication devices 30-2 and 30-3 are devices that perform single-core bidirectional transmission. The communication device 30-1 that performs two-core transmission is connected to the optical node device 10 via different optical transmission paths L (two optical transmission paths L) for transmission and reception. The communication devices 30-2 and 30-3 that perform single-core bidirectional transmission are connected to the optical node device 10 via the same optical transmission path L (one optical transmission path L) for transmission and reception.

[0025] Although not shown in Fig. 1 for the sake of simplicity, the optical communication system 100 may include multiple optical node devices and multiple control units as shown in Fig. 7. The optical communication system 100 may include a control unit for each optical node device, or may include one control unit for multiple optical node devices. The optical node device 10 is connected to other optical node devices or communication devices via an optical transmission path L at a port different from the port to which one communication device 30 is connected. The same applies to the following embodiments.

[0026] In the following description, the direction from the communication device 30 toward the control unit 20 is referred to as the upstream direction, and the direction from the control unit 20 toward the communication device 30 is referred to as the downstream direction. The number of optical node devices 10 is not particularly limited.

[0027] The optical node device 10 is a node device that constitutes a wavelength network and accommodates one or more communication devices 30. The optical node device 10 includes multiple ports 11, multiple wavelength multiplexing / demultiplexing units 12, and multiple control transceivers 13. For the sake of simplicity, Fig. 1 only shows the configuration of the optical node device 10 for transmitting and receiving control signal light between the control unit 20 and each communication device 30. However, the optical node device 10 also includes a forwarding function for forwarding optical signals to other optical node devices or communication devices.

[0028] One or more communication devices 30 are connected to the multiple ports 11 via optical transmission lines L. The communication device 30-1 is a device that performs two-core transmission, and is therefore connected to two ports 11 via two optical transmission lines L. In the example shown in FIG. 1 , the communication device 30-1 is connected to ports 11-1 and 11-2 via two optical transmission lines L.

[0029] Since the communication devices 30-2 and 30-2 are devices that perform single-core bidirectional transmission, they are connected to one port 11 via one optical transmission path L. In the example shown in FIG. 1, the communication device 30-2 is connected to port 11-4 via one optical transmission path L. The communication device 30-3 is connected to port 11-5 via one optical transmission path L. Note that each communication device 30 may be connected to any port 11 provided in the optical node device 10.

[0030] A wavelength multiplexing / demultiplexing unit 12 is installed for each port 11 and connected to a different control transceiver 13. Wavelength multiplexing / demultiplexing unit 12-m (m is an integer greater than or equal to 1) has a first port, a second port, and a third port. The first port of wavelength multiplexing / demultiplexing unit 12-m (m is an integer greater than or equal to 1) is connected to port 11-m (m is an integer greater than or equal to 1) via optical wiring. The second port of wavelength multiplexing / demultiplexing unit 12-m (m is an integer greater than or equal to 1) is connected to control transceiver 13-m (m is an integer greater than or equal to 1) via optical wiring. The third port of wavelength multiplexing / demultiplexing unit 12-m (m is an integer greater than or equal to 1) is connected to a forwarding function via optical wiring.

[0031] The wavelength multiplexing / demultiplexing unit 12-m separates the multiplexed signal light (for example, multiplexed signal light of upstream control signal light and main signal light) input from port 11-m. The wavelength multiplexing / demultiplexing unit 12-m outputs the separated upstream control signal light toward the control transceiver 13-m. The wavelength multiplexing / demultiplexing unit 12-m outputs the separated main signal light to a forwarding function in a subsequent stage. In this way, the wavelength multiplexing / demultiplexing unit 12-m has the function of separating the multiplexed signal light input from the first port and outputting it from the second and third ports.

[0032] Furthermore, the wavelength multiplexing / demultiplexing unit 12-m wavelength-multiplexes the downstream control signal light output from the control transceiver 13-m with the main signal light output from the forwarding function, and outputs the result via the port 11-m toward the communication device 30. In this way, the wavelength multiplexing / demultiplexing unit 12-m has the function of wavelength-multiplexing the optical signal (downstream control signal light) input from the second port and the optical signal (main signal light) input from the third port, and outputting the result from the first port.

[0033] The wavelength multiplexing / demultiplexing unit 12-m is connected to the port 11-m via optical wiring. Therefore, the separation of the upstream control signal light and the main signal light, and the wavelength multiplexing of the downstream control signal light and the main signal light are performed regardless of the type of transmission method (two-core transmission or single-core bidirectional transmission) of the communication device 30 that is the source or destination of the optical signal.

[0034] The wavelength multiplexing / demultiplexing unit 12-m can be, for example, a wavelength filter having wavelength characteristics that reflect the wavelengths of the downstream control signal light and the upstream control signal light and transmit the wavelength band of the main signal light that can be transmitted by the communication device 30. The wavelength characteristics of the wavelength filter may be characteristics that transmit the wavelengths of the downstream control signal light and the upstream control signal light and reflect the wavelength band of the main signal light that can be transmitted by the communication device 30.

[0035] The control transceiver 13 is a single-fiber bidirectional transmission type transceiver. A single-fiber bidirectional transmission type transceiver is a transceiver that can transmit and receive optical signals via a single optical transmission line L. Therefore, the control transceiver 13-m includes a wavelength multiplexer / demultiplexer 131, a receiver 132, and a transmitter 133.

[0036] The wavelength multiplexing / demultiplexing unit 131 has wavelength characteristics that reflect the wavelength of the downstream control signal light sent from the transmitter 133 and transmit the wavelength of the upstream control signal light. The wavelength multiplexing / demultiplexing unit 131 has a first port, a second port, and a third port. The first port of the wavelength multiplexing / demultiplexing unit 131 is connected to the transmitter 133. The second port of the wavelength multiplexing / demultiplexing unit 131 is connected to the wavelength multiplexing / demultiplexing unit 12 via optical wiring. The third port of the wavelength multiplexing / demultiplexing unit 131 is connected to the receiver 132.

[0037] The wavelength multiplexing / demultiplexing unit 131 outputs the downstream control signal light input to the first port from the second port toward the wavelength multiplexing / demultiplexing unit 12, and outputs the upstream control signal light input to the second port from the third port toward the receiver 132. The wavelength characteristics of the wavelength multiplexing / demultiplexing unit 131 may be such that it transmits the wavelength of the downstream control signal light and reflects the wavelength of the upstream control signal light.

[0038] The receiver 132 receives the upstream control signal light. For example, the receiver 132 receives the upstream control signal light output from the third port of the wavelength multiplexing / demultiplexing unit 131. The receiver 132 outputs the received upstream control signal light to the control unit 20. The transmitter 133 transmits the downstream control signal light at a predetermined wavelength. For example, the transmitter 133 transmits the downstream control signal light of a predetermined wavelength to the first port of the wavelength multiplexing / demultiplexing unit 131.

[0039] 1, each control transceiver 13 is connected to a different wavelength multiplexing / demultiplexing unit 12. For example, control transceiver 13-m is connected to wavelength multiplexing / demultiplexing unit 12-m. Control signal light is transmitted bidirectionally over a single core between the control transceiver 13 and the communication device 30. Therefore, it is desirable that the wavelength of the downstream control signal light output from the control transceiver 13 to the communication device 30 and the wavelength of the upstream control signal light output from the communication device 30 to the control transceiver 13 are different from each other.

[0040] Furthermore, since each control transceiver 13 is connected to a port 11 via a different wavelength multiplexer / demultiplexer 12, it is possible to establish a one-to-one correspondence between each port 11 and each control transceiver 13. In other words, it is possible to associate port 11-m with control transceiver 13-m.

[0041] The wavelength of the upstream control signal light output from the communication device 30 to the control transceiver 13 may be common to the communication device 30-1 that performs two-core transmission and the communication devices 30-1 and 30-2 that perform single-core bidirectional transmission. In the first embodiment, regardless of the type of transmission method of the communication device 30, the wavelength of the downstream control signal light transmitted by the control transceiver 13 is set to λ １ and the wavelength of the upstream control signal light transmitted by the communication device 30 is λ １ ´.

[0042] The control unit 20 controls the optical node device 10 and the communication device 30. Here, the control of the optical node device 10 includes, for example, control of the transmission of downstream control signal light by the control transceiver 13, and connection settings between ports in the forwarding function (for example, setting of a forwarding path). The control of the communication device 30 includes, for example, processes such as authentication and registration with a new connecting device, allocation of an emission wavelength to the communication device 30, instructions to stop light and to change the wavelength, etc.

[0043] The control unit 20 performs the above-mentioned control on the communication devices 30 (including, for example, communication devices 30 already connected to the optical node device 10 and newly connected devices) connected to the optical node device 10. Furthermore, the control unit 20 performs route control and the like in the optical node device 10 so that the communication devices 30 can communicate with subscriber devices with which they will communicate. Furthermore, the control unit 20 is connected to each control transceiver 13, and causes each control transceiver 13 to transmit downstream control signal light.

[0044] Furthermore, the control unit 20 identifies the port to which the new connecting device is connected based on the upstream control signal light received by the control transceiver 13. As described above, each port 11 and each control transceiver 13 are associated one-to-one. Therefore, the control unit 20 can recognize that the new connecting device is connected to the port 11 associated with the control transceiver 13 from which the upstream control signal light was received.

[0045] The control unit 20 also holds port management information related to the ports of the optical node device 10 to which each communication device 30 is connected via the optical transmission path L. For example, the port management information registers information indicating paired ports among the multiple ports 11 provided in the optical node device 10. Therefore, when the control unit 20 identifies a port 11 connected to a new connection device, it can identify other ports 11 paired with the identified port 11. Hereinafter, two paired ports 11 may also be referred to as a pair of ports 11.

[0046] The communication device 30 performs two-core transmission or single-core bidirectional transmission. The communication device 30 performing two-core transmission includes a control signal transmitter 31, a control signal receiver 32, a main signal transmitter 33, a main signal receiver 34, a wavelength multiplexing / demultiplexing unit 35, and a wavelength multiplexing / demultiplexing unit 36. The communication device 30 performing single-core bidirectional transmission includes a control signal transmitter 31, a control signal receiver 32, a main signal transmitter 33, a main signal receiver 34, and a wavelength multiplexing / demultiplexing unit 37.

[0047] The control signal transmitter 31 is a transmitter used to transmit control signals. The control signal transmitter 31 transmits upstream control signal light at a predetermined wavelength. The control signal receiver 32 is a receiver used to receive control signals. The control signal receiver 32 receives downstream control signal light transmitted from the optical node device 10. The control signal receiver 32 has the function of detecting and demodulating optical signals.

[0048] The main signal transmitter 33 is a transmitter used to transmit a main signal. The main signal transmitter 33 transmits an optical main signal toward a communication device of a communication partner. The wavelength of the optical main signal transmitted by the main signal transmitter 33 provided in the communication device 30-1 performing two-core transmission may be assigned to the communication device 30 by the control unit 20 and notified by the control unit 20. The notification of the wavelength can be notified as a downstream control signal. The main signal receiver 34 is a receiver used to receive the main signal. The main signal receiver 34 receives the optical main signal transmitted from the communication device of the communication partner.

[0049] In addition, when the communication device 30 performing two-core transmission is configured to use a part of the output light from the light source for the optical signal as local light, the same wavelength is assigned to the transmission wavelength and the reception wavelength. As an example, the communication device 30-1 performing two-core transmission has λ ２ is assigned to the .

[0050] The wavelength multiplexing / demultiplexing unit 35 is connected to a transmission port of the communication device 30. The transmission port is a port used for transmitting optical signals. The wavelength multiplexing / demultiplexing unit 35 wavelength-multiplexes the upstream control signal light sent from the control signal transmitter 31 and the main signal light sent from the main signal transmitter 33, and outputs the multiplexed signal light from the transmission port toward the optical node device 10.

[0051] The wavelength multiplexing / demultiplexing unit 36 ​​is connected to a receiving port of the communication device 30. The receiving port is a port used for receiving optical signals. The wavelength multiplexing / demultiplexing unit 36 ​​separates the multiplexed signal light (e.g., multiplexed signal light of downstream control signal light and main signal light) input from the optical node device 10. The wavelength multiplexing / demultiplexing unit 36 ​​outputs the separated downstream control signal light to the control signal receiver 32 and outputs the separated main signal light to the main signal receiver 34.

[0052] In current transmission networks based on two-core transmission configured with transmission devices such as ROADM (Reconfigurable Optical Add-Drop Multiplexer), a configuration is often used in which two optical transmission paths are monitored using a monitoring control signal of the same wavelength. However, if the wavelength of the upstream control signal light and the wavelength of the downstream control signal light are different in the configuration of Figure 1, control signal light of different wavelengths is transmitted to the two optical transmission paths connecting the communication device 30-1 performing two-core transmission and the optical node device 10.

[0053] The control signal transmitter 31, control signal receiver 32, main signal transmitter 33, and main signal receiver 34 provided in the communication devices 30-2 and 30-2 performing single-fiber bidirectional transmission operate as described above. The wavelength of the main signal light sent by the main signal transmitter 33 provided in the communication devices 30-2 and 30-2 performing single-fiber bidirectional transmission may be assigned to the communication device 30 by the control unit 20 and notified by the control unit 20. The notification of the wavelength can be notified as a downstream control signal.

[0054] In addition, the communication devices 30-2 and 30-2 that perform single-fiber bidirectional transmission generally have different transmission wavelengths and reception wavelengths. ３ is assigned, and the receiving wavelength λ ３ In addition, as an example, the communication device 30-3 that performs single-core bidirectional transmission has a transmission wavelength of λ ４ is assigned, and the receiving wavelength λ ４ ' is assigned to the

[0055] The wavelength multiplexing / demultiplexing unit 37 is connected to a transmission / reception port of the communication device 30. The transmission / reception port is a port used for both transmitting and receiving optical signals. The wavelength multiplexing / demultiplexing unit 37 wavelength-multiplexes the upstream control signal light sent from the control signal transmitter 31 and the main signal light sent from the main signal transmitter 33, and outputs the multiplexed signal light from the transmission / reception port toward the optical node device 10. The wavelength multiplexing / demultiplexing unit 37 demultiplexes the multiplexed signal light (e.g., multiplexed signal light of downstream control signal light and main signal light) input from the optical node device 10 side. The wavelength multiplexing / demultiplexing unit 36 ​​outputs the demultiplexed downstream control signal light to the control signal receiver 32, and outputs the demultiplexed main signal light to the main signal receiver 34.

[0056] To connect a communication device 30 that performs two-core transmission to the optical node device 10, two optical transmission lines L are drawn in and connected to the transmitting port and receiving port of the communication device 30. At this time, the user connects a pair of unused optical transmission lines L that are registered as a pair in the control unit 20 to the transmitting port and receiving port of the communication device 30. At this time, the user may connect either of the pair of optical transmission lines L to the transmitting port of the communication device 30.

[0057] When connecting a communication device 30 that performs single-core bidirectional transmission to the optical node device 10, one of the unused optical transmission lines L is drawn in and connected to the transmitting / receiving port of the communication device 30.

[0058] When a communication device 30 before optical path opening is newly connected to the optical node device 10, it exchanges information necessary for registration and authentication and for optical path opening with the control unit 20. The information necessary for optical path opening includes, for example, information on the wavelengths used for transmission and reception, and information indicating the communication device to be communicated with. The communication device 30 may output upstream control signal light to the control unit 20 as an optical signal with a wavelength different from that of the main signal light. The communication device 30 is, for example, an ONU (Optical Network Unit) installed in a subscriber's premises.

[0059] 1, the communication device 30-1 performing dual-core transmission can transmit an upstream control signal optical signal from a control signal transmitter 31-1 toward one control transceiver 13 (for example, the control transceiver 13-1), and can receive a downstream control signal optical signal transmitted from another control transceiver 13 (for example, the control transceiver 13-2) at a control signal receiver 32-1. In other words, the communication device 30-1 performing dual-core transmission can exchange control signals with the control unit 20 using two control transceivers 13.

[0060] In addition, communication devices 30-2 and 30-3 that perform single-core bidirectional transmission can exchange control signals with the control unit 20 by transmitting upstream control signal light and downstream control signal light bidirectionally over one core between them and a single control transceiver 13 (e.g., control transceivers 13-4 and 13-5) that has the same function as the control transceiver 13 used for communication with communication device 30-1 that performs two-core transmission.

[0061] 2 to 5, an initial connection method will be described in which the control unit 20 performs authentication and registration processing on a new connection device when a new communication device 30 is connected to the optical node device 10. There are two initial connection methods: a first initial connection method and a second initial connection method. Each initial connection method will be described in detail below.

[0062] (First Initial Connection Method) The first initial connection method is a method in which an initial connection is made by two control transceivers 13 connected to a pair of ports 11 via the wavelength multiplexing / demultiplexing unit 12, respectively, transmitting the same downstream control signal light. Figure 2 is a diagram for explaining how the first initial connection method performed by the optical communication system 100 in the first embodiment is started.

[0063] 2 shows a case where a communication device 30-1 performing two-core transmission and communication devices 30-2 and 30-3 performing single-core bidirectional transmission are newly connected to the optical node device 10. In explaining the first initial connection method, it is assumed that pairs of ports 11 are registered in advance in the port management information. For example, it is assumed that the pairs of ports 11, namely, the pair of port 11-1 and port 11-2, the pair of port 11-3 and port 11-4, and the pair of port 11-5 and port 11-6, are registered in the port management information as pairs of ports 11.

[0064] First, suppose that a communication device 30-1 performing two-core transmission is newly connected to the optical node device 10. For example, suppose that the communication device 30-1 is connected to each of ports 11-1 and 11-2 of the optical node device 10 via optical transmission paths L. When the communication device 30-1 performing two-core transmission is connected to the optical node device 10, the transmitter 133 of the control transceiver 13-1 connected to the port 11-1 to which the communication device 30-1 is connected via the wavelength multiplexing / demultiplexing unit 12-1 and the transmitter 133 of the control transceiver 13-2 connected to the port 11-2 registered as a pair with the port 11-1 via the wavelength multiplexing / demultiplexing unit 12-2 send out the same downstream control signal light. The port to which the newly connected device is connected may be provided with an optical detector for each port, for example, and the port in which an optical input is detected may be identified as the port to which the newly connected device is connected.

[0065] As a result of the downstream control signal light being transmitted from the control transceiver 13-1 and the control transceiver 13-2, the downstream control signal light is input to the communication device 30-1 via different optical transmission paths L. For example, the downstream control signal light transmitted by the transmitter 133 of the control transceiver 13-1 is input to a wavelength multiplexing / demultiplexing unit 35-1 provided in the transmitting port of the communication device 30-1, and the downstream control signal light transmitted by the transmitter 133 of the control transceiver 13-2 is input to a wavelength multiplexing / demultiplexing unit 36-1 provided in the receiving port of the communication device 30-1.

[0066] The downstream control signal light input to the wavelength multiplexing / demultiplexing unit 35-1 is output toward the control signal transmitter 31-1. However, the control signal transmitter 31-1 does not have the function of detecting and demodulating an optical signal, and therefore cannot receive the downstream control signal light. On the other hand, the downstream control signal light input to the wavelength multiplexing / demultiplexing unit 36-1 of the communication device 30-1 is output toward the control signal receiver 32-1.

[0067] The control signal receiver 32-1 has the function of detecting and demodulating an optical signal, and is therefore capable of receiving downstream control signal light. Receiving this downstream control signal light triggers the communication device 30-1, which performs two-core transmission, to start transmitting an upstream control signal from the control signal transmitter 31-1. This allows the communication device 30-1, which performs two-core transmission, to start exchanging control signals with the control unit 20 using the two control transceivers 13-1 and 13-2. As a result, the control unit 20 can proceed with the authentication and registration process for the communication device 30-1.

[0068] In addition, the communication device 30-1 may declare the type of transmission method of its own device (two-core transmission), and under control of the control unit 20, the optical node device 10 may stop the emission of light from the transmitter 133 of the control transceiver 13-1, which is connected to the port 11-1 to which the transmitter of the communication device 30-1 is connected via the wavelength multiplexing / demultiplexing unit 12-1.

[0069] Next, suppose that a communication device 30-2 performing single-fiber bidirectional transmission is newly connected to the optical node device 10. For example, suppose that the communication device 30-2 is connected to port 11-4 of the optical node device 10 via an optical transmission path L. When the communication device 30-2 performing single-fiber bidirectional transmission is connected to the optical node device 10, the transmitter 133 of the control transceiver 13-4 connected to the port 11-4 to which the communication device 30-2 is connected via the wavelength multiplexing / demultiplexing unit 12-4 and the transmitter 133 of the control transceiver 13-3 connected to port 11-3 registered as a pair with port 11-4 via the wavelength multiplexing / demultiplexing unit 12-3 send out the same downstream control signal light.

[0070] Downstream control signal light is transmitted from the control transceiver 13-3 and the control transceiver 13-4, but no communication device 30 is connected to port 11-3. Therefore, the downstream control signal light transmitted from the transmitter 133 of the control transceiver 13-3 is not input to any of the communication devices 30. On the other hand, the downstream control signal light transmitted from the control transceiver 13-4 is input to the communication device 30-2. For example, the downstream control signal light transmitted from the transmitter 133 of the control transceiver 13-4 is input to the wavelength multiplexing / demultiplexing unit 37-2 provided in the transmission / reception port of the communication device 30-2.

[0071] In this way, when a communication device 30 performing single-core bidirectional transmission is connected, downstream control signal light sent by one of the control transceivers 13 is input to the wavelength multiplexing / demultiplexing unit 37 of the communication device 30 performing single-core bidirectional transmission, regardless of which port 11 the communication device 30 performing single-core bidirectional transmission is connected to.

[0072] The downstream control signal light input to the wavelength multiplexing / demultiplexing unit 37-2 is output toward the control signal receiver 32-2. The control signal receiver 32-2 has the function of detecting and demodulating optical signals, and is therefore able to receive the downstream control signal light. Receiving this downstream control signal light triggers the communication device 30-2 performing single-fiber bidirectional transmission to start transmitting an upstream control signal. This allows the communication device 30-2 performing single-fiber bidirectional transmission to start exchanging control signals with the control unit 20 using one control transceiver 13-4. As a result, the control unit 20 can proceed with the authentication and registration process for the communication device 30-2. The same applies to the communication device 30-3 performing single-fiber bidirectional transmission.

[0073] 2 shows a configuration in which both the communication device 30-2 connected to the older port 11 of the pair of ports 11 and the communication device 30-3 connected to the younger port 11 of the pair of access ports can start receiving downstream control signal light. At this time, the communication devices 30-2 and 30-3 declare the type of transmission method of their own devices (single-core bidirectional transmission), and under control of the control unit 20, the optical node device 10 may stop light emission from the transmitters 133 of the control transceivers 13-3 and 13-6 connected via the wavelength multiplexing and demultiplexing units 12-3 and 12-6 to the ports 11-3 and 11-6 registered as the pair of ports 11-4 and 11-5 to which the communication devices 30-2 and 30-3 are connected, respectively.

[0074] Furthermore, when the control unit 20 determines from the notification from the communication devices 30-2 and 30-3 that the communication devices 30-2 and 30-3 are communication devices that perform single-core bidirectional transmission, the control unit 20 may cancel the pairing of the ports 11-3 and 11-6 that are registered in the port management information as the pair of the ports 11-4 and 11-5 to which the communication devices 30-2 and 30-3 are connected, respectively. In this case, the ports 11-3 and 11-6 whose pairing has been canceled remain unused, and the control unit 20 may use them as the port 11 to which the newly connected communication device 30 that performs single-core bidirectional transmission will be connected later.

[0075] Although not shown in FIG. 2, the control signal transmitter 31 and main signal transmitter 33 in the communication device 30 may emit light during the procedure of the first initial connection method.

[0076] In the first initial connection method described above, when a new communication device 30 is connected to the optical node device 10, the two control transceivers 13 connected to each of the pair of ports 11 via the wavelength multiplexing / demultiplexing unit 12 transmit the same downstream control signal. This makes it possible to receive downstream control signal light regardless of the type of transmission method (two-core transmission or single-core bidirectional transmission) of the communication device 30. Therefore, the initial connection procedure can be carried out.

[0077] 3 is a sequence diagram showing the processing flow of the first initial connection method performed by the optical communication system 100 in the first embodiment. Assume that a user connects two optical transmission paths L to the communication device 30-1 to connect to the optical node device 10 (step S101). As a result, as shown in FIG. 2, the wavelength multiplexing / demultiplexing unit 35-1 of the communication device 30-1 is connected to port 11-1 of the optical node device 10 via the optical transmission paths L, and the wavelength multiplexing / demultiplexing unit 36-1 of the communication device 30-1 is connected to port 11-2 of the optical node device 10 via the optical transmission path L.

[0078] However, the control unit 20 cannot determine which of the multiple ports 11 of the optical node device 10 the communication device 30-1 is connected to. After connecting to the optical node device 10, the communication device 30-1 generates an upstream control signal including requests for authentication, registration, etc. The control signal transmitter 31-1 of the communication device 30-1 converts the generated upstream control signal into an optical signal and sends it out as upstream control signal light (step S102).

[0079] The upstream control signal light sent from the control signal transmitter 31-1 of the communication device 30-1 is input to the port 11-1 of the optical node device 10. The upstream control signal light input to the port 11-1 is output by the wavelength multiplexing / demultiplexing unit 12-1 toward the control transceiver 13-1. The wavelength multiplexing / demultiplexing unit 131 of the control transceiver 13-1 outputs the upstream control signal light output from the wavelength multiplexing / demultiplexing unit 12-1 to the receiver 132. The receiver 132 detects and demodulates the upstream control signal light. The receiver 132 outputs the demodulated upstream control signal to the control unit 20 via a control line (not shown) (step S103).

[0080] In response to receiving the upstream control signal, the control unit 20 recognizes that the new connection device has been connected to the optical node device 10. Then, the control unit 20 identifies that the new connection device has been connected to the port 11-1 associated with the control transceiver 13-1 that includes the receiver 132 that output the upstream control signal.

[0081] Alternatively, a light detector that detects light input to the port 11 may be provided for each port 11, and the control unit 20 may identify the port 11 to which the new connecting device is connected based on the detection result of the light detector. In this case, the light detector that detects the input of light transmits port identification information to the control unit 20, including identification information for identifying the light detector and information indicating that the input of light has been detected (e.g., a light intensity value). The control unit 20 stores information that associates the identification information of the light detector with each port 11, thereby being able to identify the port 11 to which the light has been input based on the identification information of the light detector included in the port identification information. Note that the light detector may detect the optical input of either an upstream control signal light or a main signal light. In this case, steps S102 and S103 are not necessarily required, and the new connecting device may generate an upstream control signal required for authentication and registration in step S107 (described later) and thereafter, and output it from the control signal transmitter 31-1.

[0082] The control unit 20 then refers to the port management information to identify the port 11-2 that is registered as a pair with the identified port 11-1. The control unit 20 then transmits a transmission command, including an instruction to transmit a downstream control signal, to each of the control transceiver 13-1 associated with the port 11-1 and the control transceiver 13-2 associated with the port 11-2 (step S104).

[0083] The control transceiver 13-1 and the control transceiver 13-2 transmit the same downstream control signal light (for example, wavelength λ １ The downstream control signal light transmitted from the transmitter 133 of the control transceiver 13-1 is output from port 11-1 via the wavelength multiplexing / demultiplexing unit 12-1 and input to the wavelength multiplexing / demultiplexing unit 35-1 of the communication device 30-1 (step S105). The downstream control signal light transmitted from the transmitter 133 of the control transceiver 13-2 is output from port 11-2 via the wavelength multiplexing / demultiplexing unit 12-2 and input to the wavelength multiplexing / demultiplexing unit 36-1 of the communication device 30-1.

[0084] The downstream control signal light input to the wavelength multiplexing / demultiplexing unit 35-1 is output toward the control signal transmitter 31-1. However, the control signal transmitter 31-1 does not have the function of detecting and demodulating optical signals, and therefore is unable to receive the downstream control signal light. On the other hand, the downstream control signal light input to the wavelength multiplexing / demultiplexing unit 36-1 of the communication device 30-1 is output toward the control signal receiver 32-1. The control signal receiver 32-1 has the function of detecting and demodulating optical signals, and therefore is able to receive the downstream control signal light. In this way, in the communication device 30-1 performing dual-core transmission, the same downstream control signal light is input from two paths, and the communication device 30-1 receives the downstream control signal light input from one path (step S106).

[0085] Upon receiving the downstream control signal light, the communication device 30-1 transmits an upstream control signal from the control signal transmitter 31-1 (step S107). The upstream control signal light transmitted from the control signal transmitter 31-1 is input to the port 11-1 of the optical node device 10. The upstream control signal light input to the port 11-1 of the optical node device 10 is output to the control transceiver 13-1 by the wavelength multiplexing / demultiplexing unit 12-1. The receiver 132 of the control transceiver 13-1 receives the upstream control signal light. The receiver 132 of the control transceiver 13-1 detects and demodulates the received upstream control signal light and outputs it to the control unit 20 (step S108). Thereafter, the control unit 20 exchanges control signal light containing information necessary for authentication, registration, and optical path opening with the communication device 30-1 via the control transceiver 13-2 (step S109).

[0086] Assume that a user connects one optical transmission path L to the communication device 30-2 to connect to the optical node device 10 (step S110). As a result, as shown in FIG. 2, assume that the wavelength multiplexing / demultiplexing unit 37-2 of the communication device 30-2 is connected to the port 11-4 of the optical node device 10 via the optical transmission path L.

[0087] However, the control unit 20 cannot determine which of the multiple ports 11 of the optical node device 10 the communication device 30-2 is connected to. After connecting to the optical node device 10, the communication device 30-2 generates an upstream control signal including requests for authentication, registration, etc. The control signal transmitter 31-2 of the communication device 30-2 converts the generated upstream control signal into an optical signal and sends it out as upstream control signal light (step S111).

[0088] The upstream control signal light sent from the control signal transmitter 31-2 of the communication device 30-2 is input to port 11-4 of the optical node device 10. The upstream control signal light input to port 11-4 is output by the wavelength multiplexing / demultiplexing unit 12-4 toward the control transceiver 13-4. The wavelength multiplexing / demultiplexing unit 131 of the control transceiver 13-4 outputs the upstream control signal light output from the wavelength multiplexing / demultiplexing unit 12-4 to the receiver 132. The receiver 132 detects and demodulates the upstream control signal light. The receiver 132 outputs the demodulated upstream control signal to the control unit 20 via a control line (not shown) (step S112).

[0089] In response to receiving the upstream control signal, the control unit 20 recognizes that the new connection device has been connected to the optical node device 10. Then, the control unit 20 identifies that the new connection device has been connected to the port 11-4 associated with the control transceiver 13-4 that includes the receiver 132 that output the upstream control signal.

[0090] Alternatively, a light detector that detects light input to the port 11 may be provided for each port 11, and the control unit 20 may identify the port 11 to which the new connecting device is connected based on the detection result of the light detector. In this case, the light detector that detects the input of light transmits port identification information to the control unit 20, including identification information for identifying the light detector and information indicating that the input of light has been detected (e.g., a light intensity value). The control unit 20 stores information that associates the identification information of the light detector with each port 11, thereby being able to identify the port 11 to which light has been input based on the identification information of the light detector included in the port identification information. Note that the light detector may detect the optical input as either an upstream control signal light or a main signal light. In this case, steps S111 and S112 are not necessarily required, and the new connecting device may generate an upstream control signal required for authentication and registration in step S116 or later, which will be described later, and output it from the control signal transmitter 31-2.

[0091] The control unit 20 then refers to the port management information to identify the port 11-3 that is registered as a pair with the identified port 11-4. The control unit 20 then transmits a transmission command, including an instruction to transmit a downstream control signal, to each of the control transceiver 13-3 associated with the port 11-3 and the control transceiver 13-4 associated with the port 11-4 (step S113).

[0092] The control transceiver 13-3 and the control transceiver 13-4 transmit the same downstream control signal light (for example, wavelength λ １ The downstream control signal light transmitted from the transmitter 133 of the control transceiver 13-3 is output from the port 11-3 via the wavelength multiplexing / demultiplexing unit 12-3. However, nothing is connected to the optical transmission line L connected to the port 11-3. Therefore, the downstream control signal light output from the port 11-3 is not received by any of the communication devices 30.

[0093] The downstream control signal light sent from the transmitter 133 of the control transceiver 13-4 is output from port 11-4 via the wavelength multiplexing / demultiplexing unit 12-4 and input to the wavelength multiplexing / demultiplexing unit 37-2 of the communication device 30-2. The downstream control signal light input to the wavelength multiplexing / demultiplexing unit 37-2 is output to the control signal receiver 32-2. The control signal receiver 32-2 has the function of detecting and demodulating optical signals, and is therefore able to receive the downstream control signal light. In this way, in the communication device 30-2 that performs single-core bidirectional transmission, the downstream control signal light is input from one path and the input downstream control signal light is received (step S115).

[0094] Upon receiving the downstream control signal light, the communication device 30-2 transmits an upstream control signal light from the control signal transmitter 31-2 (step S116). The upstream control signal light transmitted from the control signal transmitter 31-2 is input to the port 11-4 of the optical node device 10. The upstream control signal light input to the port 11-4 of the optical node device 10 is output to the control transceiver 13-4 by the wavelength multiplexing / demultiplexing unit 12-4. The receiver 132 of the control transceiver 13-4 receives the upstream control signal light. The receiver 132 of the control transceiver 13-4 detects and demodulates the received upstream control signal light and outputs it to the control unit 20 (step S117). Thereafter, the control unit 20 exchanges control signal light containing information necessary for authentication, registration, and optical path opening with the communication device 30-2 via the control transceiver 13-4 (step S118).

[0095] (Second initial connection method) The second initial connection method is a method in which a new connection device performs an initial connection by declaring the type of transmission method (single-core bidirectional transmission or two-core transmission) when exchanging control signals for authentication and registration with the control unit 20. Fig. 4 is a diagram for explaining the start of the second initial connection method performed by the optical communication system 100 in the first embodiment.

[0096] 4 shows a case where a communication device 30-1 performing two-core transmission and communication devices 30-2 and 30-3 performing single-core bidirectional transmission are newly connected to the optical node device 10. In explaining the second initial connection method, it is assumed that pairs of ports 11 are registered in advance in the port management information. For example, it is assumed that the pair of ports 11-1 and 11-2, the pair of ports 11-3 and 11-4, and the pair of ports 11-5 and 11-6 are registered as pairs of ports 11 in the port management information.

[0097] First, assume that a communication device 30-1 that performs two-core transmission is newly connected to the optical node device 10. For example, assume that the communication device 30-1 is connected to ports 11-1 and 11-2 of the optical node device 10 via an optical transmission path L. When the communication device 30-1 that performs two-core transmission is connected to the optical node device 10, the control signal transmitter 31 of the communication device 30-1 converts an upstream control signal that includes type information indicating the type of transmission method of the device itself (two-core transmission) into an optical signal and sends it out as upstream control signal light.

[0098] The upstream control signal light sent from the communication device 30-1 is input to the port 11-1 of the optical node device 10. The control transceiver 13-1 connected to the port 11-1 via the wavelength multiplexing / demultiplexing unit 12-1 can receive the upstream control signal light sent from the control signal transmitter 31-1 of the communication device 30-1. The receiver 132 of the control transceiver 13-1 outputs the upstream control signal obtained by detecting and demodulating the upstream control signal light to the control unit 20. The control unit 20 can recognize that the communication device 30-1 is a communication device that performs two-core transmission based on the type information included in the upstream control signal.

[0099] When the communication device 30-1 is a communication device performing two-core transmission, the control unit 20 refers to the port management information and identifies the port 11 registered as a pair with the port 11-1 connected to the control transceiver 13-1 that received the upstream control signal light via the wavelength multiplexing / demultiplexing unit 12-1. The control unit 20 then causes the control transceiver 13-2, which is connected to the identified port 11-2 via the wavelength multiplexing / demultiplexing unit 12-2, to send a downstream control signal addressed to the communication device 30-1. This allows the communication device 30-1 performing two-core transmission to start exchanging control signals with the control unit 20 using the two control transceivers 13-1 and 13-2. As a result, the control unit 20 can proceed with the authentication and registration process for the communication device 30-1.

[0100] Under control of the control unit 20, the optical node device 10 may stop light emission from the transmitter 133 of the control transceiver 13-1 connected to the port 11-1 to which the transmitter of the communication device 30-1 is connected via the wavelength multiplexing / demultiplexing unit 12-1.

[0101] Next, suppose that a communication device 30-2 that performs single-fiber bidirectional transmission is newly connected to the optical node device 10. For example, suppose that the communication device 30-2 is connected to port 11-4 of the optical node device 10 via an optical transmission path L. When the communication device 30-2 that performs single-fiber bidirectional transmission is connected to the optical node device 10, the control signal transmitter 31-2 of the communication device 30-2 converts an upstream control signal that includes type information indicating the type of transmission method of its own device (single-fiber bidirectional transmission) into an optical signal and sends it out as upstream control signal light.

[0102] The upstream control signal light sent from the communication device 30-2 is input to port 11-4 of the optical node device 10. The optical node device 10 is provided with a control transceiver 13 for single-fiber bidirectional transmission via a wavelength multiplexing / demultiplexing unit 12 for each port 11. Therefore, when a communication device 30-2 performing single-fiber bidirectional transmission is connected, any of the control transceivers 13 provided in the optical node device 10 can receive the upstream control signal light sent by the communication device 30-2, regardless of which port 11 the communication device 30-2 is connected to. The receiver 132 of the control transceiver 13-4 outputs an upstream control signal obtained by detecting and demodulating the upstream control signal light to the control unit 20. The control unit 20 can recognize that the communication device 30-2 is a communication device performing single-fiber bidirectional transmission based on the type information included in the upstream control signal.

[0103] When the communication device 30-2 is a communication device that performs single-core bidirectional transmission, the control unit 20 causes the control transceiver 13-4, which has received the upstream control signal, to send a downstream control signal addressed to the communication device 30-2. This allows the communication device 30-2 that performs single-core bidirectional transmission to start exchanging control signals with the control unit 20 using one control transceiver 13-4. The control transceiver 13-4 is a control transceiver 13 that has the same configuration as the one used for communication with the communication device 30-1 that performs two-core transmission. As a result, the control unit 20 can proceed with the authentication and registration process for the communication device 30-1.

[0104] In addition, under control of the control unit 20, the optical node device 10 may stop the emission of light from the transmitter 133 of the control transceiver 13-3, which is connected via the wavelength multiplexing / demultiplexing unit 12-3 to port 11-3, which is registered as a pair with port 11-4 to which the transmitter of the communication device 30-2 is connected.

[0105] Furthermore, when the optical node device 10 determines from a report from the communication device 30-2 that the communication device 30-2 is a communication device that performs single-core bidirectional transmission, the optical node device 10 may cancel the pairing of the port 11-3 that is registered in the port management information as a pair with the port 11-4 to which the communication device 30-2 is connected. In this case, since the port 11-3 whose pairing has been canceled remains unused, the control unit 20 may use it as the port 11 to which a newly connected communication device 30 that performs single-core bidirectional transmission is connected later.

[0106] Although not shown in FIG. 4, the control signal transmitter 31 and main signal transmitter 33 in the communication device 30 may emit light during the procedure of the second initial connection method.

[0107] In the second initial connection method described above, when a new communication device 30 is connected to the optical node device 10, the upstream control signal light is received by one of the control transceivers 13 regardless of the type of transmission method (two-core transmission or single-core bidirectional transmission) of the communication device 30, and the control unit 20 can recognize the type of the new communication device 30. As a result, the control unit 20 can control the control transceiver 13 so that the new communication device 30 can receive the downstream control signal. Therefore, the initial connection procedure can proceed.

[0108] 5 is a sequence diagram showing the processing flow of the second initial connection method performed by the optical communication system 100 in the first embodiment. Assume that a user connects two optical transmission paths L to the communication device 30-1 to connect to the optical node device 10 (step S201). As a result, as shown in FIG. 4, the wavelength multiplexing / demultiplexing unit 35-1 of the communication device 30-1 is connected to port 11-1 of the optical node device 10 via the optical transmission path L, and the wavelength multiplexing / demultiplexing unit 36-1 of the communication device 30-1 is connected to port 11-2 of the optical node device 10 via the optical transmission path L.

[0109] However, the control unit 20 cannot determine which of the multiple ports 11 of the optical node device 10 the communication device 30-1 is connected to. After connecting to the optical node device 10, the communication device 30-1 generates an upstream control signal including type information. The control signal transmitter 31-1 of the communication device 30-1 converts the generated upstream control signal into an optical signal and sends it out as upstream control signal light (step S202).

[0110] The upstream control signal light sent from the control signal transmitter 31-1 of the communication device 30-1 is input to the port 11-1 of the optical node device 10. The upstream control signal light input to the port 11-1 is output by the wavelength multiplexing / demultiplexing unit 12-1 toward the control transceiver 13-1. The wavelength multiplexing / demultiplexing unit 131 of the control transceiver 13-1 outputs the upstream control signal light output from the wavelength multiplexing / demultiplexing unit 12-1 to the receiver 132. The receiver 132 detects and demodulates the upstream control signal light. The receiver 132 outputs the demodulated upstream control signal to the control unit 20 via a control line (not shown) (step S203).

[0111] In response to receiving the upstream control signal, the control unit 20 recognizes that the new connection device has been connected to the optical node device 10. Furthermore, the control unit 20 recognizes that the communication device 30-1 is a communication device that performs two-core transmission based on the type information included in the upstream control signal (step S204). The control unit 20 also identifies that the new connection device has been connected to the port 11-1 associated with the control transceiver 13-1 that includes the receiver 132 that output the upstream control signal.

[0112] When the communication device 30-1 performs two-core transmission, the optical transmission path L used for transmission is different from the optical transmission path L used for reception. Therefore, the transmission port of the communication device 30-1 is connected to the port 11-1 to which the upstream control signal light is input. Therefore, the control unit 20 can recognize that the identified port 11-1 is connected to the transmission port of the newly connected device.

[0113] Alternatively, a light detector that detects light input to the port 11 may be provided for each port 11, and the control unit 20 may identify the port 11 to which the newly connected device is connected based on the detection result of the light detector. In this case, the light detector that detects the input of light transmits port identification information to the control unit 20, the port identification information including identification information for identifying the light detector and information indicating that the input of light has been detected (e.g., a value of light intensity). The control unit 20 stores information that associates the identification information of the light detector with each port 11, and thereby can identify the port 11 to which light has been input based on the identification information of the light detector included in the port identification information. Note that the target of the optical input detected by the light detector may be upstream control signal light or main signal light.

[0114] The control unit 20 then references the port management information and identifies the port 11-2 registered as a pair with the identified port 11-1. A pair of ports 11 are connected to the transmitting port and receiving port of the communication device 30-1 via the optical transmission path L. Therefore, the receiving port of the communication device 30-1 is connected to the port 11-2 registered as a pair with the port 11-1. Therefore, the control unit 20 causes the control transceiver 13-2, which is connected to the identified port 11-2 via the wavelength multiplexing / demultiplexing unit 12-2, to transmit a downstream control signal. As a result, the control unit 20 exchanges control signal light with the communication device 30-1, including information necessary for authentication, registration, and optical path opening (step S205).

[0115] Next, it is assumed that the user connects one optical transmission path L to the communication device 30-2 to connect to the optical node device 10 (step S206). As a result, it is assumed that the wavelength multiplexing / demultiplexing unit 37-2 of the communication device 30-2 is connected to the port 11-4 of the optical node device 10 via the optical transmission path L, as shown in FIG.

[0116] However, the control unit 20 cannot determine which of the multiple ports 11 of the optical node device 10 the communication device 30-2 is connected to. After connecting to the optical node device 10, the communication device 30-2 generates an upstream control signal including type information. The control signal transmitter 31-2 of the communication device 30-2 converts the generated upstream control signal into an optical signal and sends it out as upstream control signal light (step S207).

[0117] The upstream control signal light sent from the control signal transmitter 31-2 of the communication device 30-2 is input to port 11-4 of the optical node device 10. The upstream control signal light input to port 11-4 is output by the wavelength multiplexing / demultiplexing unit 12-4 toward the control transceiver 13-4. The wavelength multiplexing / demultiplexing unit 131 of the control transceiver 13-4 outputs the upstream control signal light output from the wavelength multiplexing / demultiplexing unit 12-4 to the receiver 132. The receiver 132 detects and demodulates the upstream control signal light. The receiver 132 outputs the demodulated upstream control signal to the control unit 20 via a control line (not shown) (step S208).

[0118] In response to receiving the upstream control signal, the control unit 20 recognizes that the new connection device has been connected to the optical node device 10. Furthermore, the control unit 20 recognizes, based on the type information included in the upstream control signal, that the communication device 30-2 is a communication device that performs single-core bidirectional transmission (step S209). The control unit 20 also identifies that the new connection device has been connected to the port 11-4 associated with the control transceiver 13-4 that includes the receiver 132 that output the upstream control signal.

[0119] Alternatively, a light detector that detects light input to the port 11 may be provided for each port 11, and the control unit 20 may identify the port 11 to which the newly connected device is connected based on the detection result of the light detector. In this case, the light detector that detects the input of light transmits port identification information to the control unit 20, the port identification information including identification information for identifying the light detector and information indicating that the input of light has been detected (e.g., a value of light intensity). The control unit 20 stores information that associates the identification information of the light detector with each port 11, and thereby can identify the port 11 to which light has been input based on the identification information of the light detector included in the port identification information. Note that the target of the optical input detected by the light detector may be upstream control signal light or main signal light.

[0120] When the communication device 30-2 performs single-core bidirectional transmission, the optical transmission path L used for transmission and the optical transmission path L used for reception are the same. Therefore, the control unit 20 causes the control transceiver 13-4, which is connected to the identified port 11-4 via the wavelength multiplexing / demultiplexing unit 12-4, to transmit a downstream control signal. As a result, the control unit 20 exchanges control signal light with the communication device 30-2, including information necessary for authentication, registration, and optical path opening (step S210).

[0121] According to the optical communication system 100 configured as described above, the optical node device 10 includes a plurality of ports 11 and one or more control transceivers 13 connected to at least one port 11 via at least one wavelength multiplexing / demultiplexing unit 12, and transmitting and receiving control signal light to and from one or more communication devices 30. Each control transceiver 13 includes a receiver 132 that receives upstream control signal light transmitted from the communication device 30 and outputs it to the control unit 20, a transmitter 133 that transmits downstream control signal light addressed to the communication device 30, and a wavelength multiplexing / demultiplexing unit 131 that outputs upstream control signal light input via the connected wavelength multiplexing / demultiplexing unit 12 to the receiver 132 and outputs downstream control signal light transmitted from the transmitter 133 to the connected wavelength multiplexing / demultiplexing unit 12.

[0122] As configured above, the optical node device 10 includes a control transceiver 13 for single-fiber bidirectional transmission associated with each port. This allows the optical node device 10 to transfer upstream control signals to the control unit 20, whether the upstream control signal light is transmitted from a communication device 30 performing two-fiber transmission or from a communication device 30 performing single-fiber bidirectional transmission. Furthermore, the optical node device 10 can transmit downstream control signal light addressed to the communication device 30 in response to an instruction from the control unit 20. This allows control signals to be exchanged with the control unit 20 regardless of the type of transmission method (single-fiber bidirectional transmission or two-fiber transmission) of the connected communication device 30.

[0123] The optical node device 10 transmits the same downstream control signal light from the control transceivers 13 connected to the port to which the new connecting device is connected and to the other ports registered as pairs with that port, regardless of whether the new connecting device performs two-core transmission or single-core bidirectional transmission. As a result, whether the new connecting device performs two-core transmission or single-core bidirectional transmission, the downstream control signal light can be received via either optical transmission path L. This makes it possible to exchange control signals with the control unit 20.

[0124] The optical node device 10 does not need to manage the ports 11 separately as a port for connection with a communication device 30 that performs two-core transmission and a port for connection with a communication device 30 that performs single-core bidirectional transmission. Therefore, regardless of the type of transmission method of the communication device 30, a new communication device can be connected to an unused port.

[0125] In the optical communication system 100, the control unit 20 cancels the pairing of the other port 11 that is paired with the port 11 connected to the communication device 30 that performs single-fiber bidirectional transmission. Then, by making the other unused port 11 connectable to another new communication device that performs single-fiber bidirectional transmission, the ports of the optical node device 10 can be used without waste in a configuration that accommodates a mixture of ports for connection to the communication device 30 that performs two-fiber transmission and communication devices that perform single-fiber bidirectional transmission. This improves convenience.

[0126] Second Embodiment In the first embodiment, a configuration in which an optical node device includes a control transceiver for each port has been described. In the second embodiment, a configuration in which a control transceiver is provided for each pair of ports will be described.

[0127] Fig. 6 is a diagram showing an example of the configuration of an optical communication system 100a in the second embodiment. The optical communication system 100a includes an optical node device 10a and a control unit 20. One or more communication devices 30 are connected to the optical node device 10a via an optical transmission path L. In the example shown in Fig. 6, three communication devices 30-1 to 30-3 are connected to the optical node device 10a via the optical transmission path L, but the number of communication devices 30 may be one or more. In the optical communication system 100a, the communication device 30-1 is a device that performs two-core transmission, and the communication devices 30-2 and 30-3 are devices that perform single-core bidirectional transmission.

[0128] The optical node device 10a is a node device that constitutes a wavelength network and accommodates one or more communication devices 30. The optical node device 10a includes multiple ports 11, multiple wavelength multiplexing / demultiplexing units 12, and multiple control transceivers 13a. For the sake of simplicity, Fig. 6 only shows the configuration of the optical node device 10a for transmitting and receiving control signal light between the control unit 20 and the communication device 30. However, the optical node device 10a also includes a forwarding function for forwarding optical signals to other optical node devices or communication devices.

[0129] The optical node device 10a differs in configuration from the optical node device 10 in that it includes a control transceiver 13a instead of the control transceiver 13. Other configurations of the optical node device 10a are similar to those of the optical node device 10. The following description will focus on the differences from the optical node device 10a.

[0130] A wavelength multiplexing / demultiplexing unit 12 is provided for each port 11 and is connected to a control transceiver 13a for the pair of ports. The wavelength multiplexing / demultiplexing unit 12 performs the same processing as in the first embodiment, except that it is connected to a control transceiver 13a for the pair of ports.

[0131] The control transceiver 13a for a pair of ports is a transceiver that can transmit and receive optical signals at each of the two ports 11. Therefore, one control transceiver 13a is connected to two wavelength multiplexing / demultiplexing units 12 that are connected to the pair of ports 11. For example, if the pair of ports 11 are port 11-1 and port 11-2, the control transceiver 13a-1 is connected to the wavelength multiplexing / demultiplexing unit 12-1 that is connected to port 11-1 and the wavelength multiplexing / demultiplexing unit 12-2 that is connected to port 11-2.

[0132] Furthermore, since the control transceiver 13a is connected to a pair of ports 11 via different wavelength multiplexing / demultiplexing units 12, it can be associated with the pair of ports 11 as being connected to the control transceiver 13a.

[0133] The control transceiver 13a includes a wavelength multiplexing / demultiplexing unit 131, a receiver 132, a transmitter 133, a wavelength multiplexing / demultiplexing unit 134, a receiver 135, and a transmitter 136. The wavelength multiplexing / demultiplexing unit 131, the receiver 132, and the transmitter 133 are used to transmit and receive optical signals at one port 11. The wavelength multiplexing / demultiplexing unit 134, the receiver 135, and the transmitter 136 are used to transmit and receive optical signals at the other paired port 11. Taking the control transceiver 13a connected to the wavelength multiplexing / demultiplexing units 12-1 and 12-2 as an example, the wavelength multiplexing / demultiplexing unit 131, the receiver 132, and the transmitter 133 are used to transmit and receive optical signals at port 11-1, and the wavelength multiplexing / demultiplexing unit 134, the receiver 135, and the transmitter 136 are used to transmit and receive optical signals at port 11-2.

[0134] In this way, the control transceiver 13a has two pairs of combinations of a wavelength multiplexing / demultiplexing unit, a transmitter, and a receiver. The control unit 20 may store information indicating which port 11 each combination of a wavelength multiplexing / demultiplexing unit, a transmitter, and a receiver included in the control transceiver 13a corresponds to. For example, the control unit 20 may store information indicating that the combination of a wavelength multiplexing / demultiplexing unit 131, a receiver 132, and a transmitter 133 corresponds to port 11-1, and the combination of a wavelength multiplexing / demultiplexing unit 134, a receiver 135, and a transmitter 136 corresponds to port 11-2.

[0135] The above example is merely an example, and the combination of two pairs of wavelength multiplexing / demultiplexing units, receivers, and transmitters provided in one control transceiver 13a may be different. Even in such a case, it is sufficient for the control unit 20 to store information indicating which combination corresponds to which port 11.

[0136] The initial connection method in the optical communication system 100a in the second embodiment is the same as that in the first embodiment, except that the configuration of the control transceiver 13a is different. An example of the first initial connection method will be described below.

[0137] (First initial connection method in the second embodiment) Assume that a user connects to the optical node device 10a by connecting two optical transmission paths L to the communication device 30-1. As a result, as shown in Fig. 6, the wavelength multiplexing / demultiplexing unit 35-1 of the communication device 30-1 is connected to the port 11-1 of the optical node device 10a via the optical transmission path L, and the wavelength multiplexing / demultiplexing unit 36-1 of the communication device 30-1 is connected to the port 11-2 of the optical node device 10a via the optical transmission path L.

[0138] However, the control unit 20 cannot determine which of the multiple ports 11 of the optical node device 10a the communication device 30-1 is connected to. After connecting to the optical node device 10a, the communication device 30-1 generates an upstream control signal including requests for authentication, registration, etc. The control signal transmitter 31-1 of the communication device 30-1 converts the generated upstream control signal into an optical signal and sends it out as upstream control signal light.

[0139] The upstream control signal light sent from the control signal transmitter 31-1 of the communication device 30-1 is input to the port 11-1 of the optical node device 10a. The upstream control signal light input to the port 11-1 is output by the wavelength multiplexing / demultiplexing unit 12-1 toward the control transceiver 13a-1. The wavelength multiplexing / demultiplexing unit 131 of the control transceiver 13a-1 outputs the upstream control signal light output from the wavelength multiplexing / demultiplexing unit 12-1 to the receiver 132. The receiver 132 detects and demodulates the upstream control signal light. The receiver 132 outputs the demodulated upstream control signal to the control unit 20 via a control line (not shown).

[0140] In response to receiving the upstream control signal, the control unit 20 recognizes that the new connection device has been connected to the optical node device 10a. Then, the control unit 20 identifies that the new connection device has been connected to the port 11 associated with the control transceiver 13a-1 that includes the receiver 132 that output the upstream control signal.

[0141] Alternatively, a light detector that detects light input to the port 11 may be provided for each port 11, and the control unit 20 may identify the port 11 to which the new connection device is connected based on the detection result of the light detector. In this case, the light detector that detects the input of light transmits port identification information to the control unit 20, including identification information for identifying the light detector and information indicating that the input of light has been detected (e.g., a light intensity value). The control unit 20 stores information correlating the identification information of the light detector with each port 11, thereby enabling the control unit 20 to identify the port 11 to which the light has been input based on the identification information of the light detector included in the port identification information. Note that the light detector may detect the optical input as either an upstream control signal light or a main signal light. In this case, the transmission of the upstream control signal light from the communication device 30-1 and the output of the upstream control signal from the control transceiver 13a-1 to the control unit 20 described above are not necessarily required. The new connection device may generate an upstream control signal required for authentication and registration after receiving the downstream control signal light described below, and output the upstream control signal from the control signal transmitter 31-1.

[0142] Thereafter, the control unit 20 transmits a transmission instruction including an instruction to transmit a downstream control signal to the control transceiver 13a-1 associated with the identified port 11.

[0143] The transmitters 133 and 136 included in the control transceiver 13a-1 transmit the same downstream control signal light (for example, wavelength λ １The downstream control signal light transmitted from the transmitter 133 of the control transceiver 13a-1 is output from port 11-1 via the wavelength multiplexing / demultiplexing unit 12-1 and input to the wavelength multiplexing / demultiplexing unit 35-1 of the communication device 30-1. The downstream control signal light transmitted from the transmitter 136 of the control transceiver 13a-1 is output from port 11-2 via the wavelength multiplexing / demultiplexing unit 12-2 and input to the wavelength multiplexing / demultiplexing unit 36-1 of the communication device 30-1.

[0144] The downstream control signal light input to the wavelength multiplexing / demultiplexing unit 35-1 is output toward the control signal transmitter 31-1. However, the control signal transmitter 31-1 does not have the function of detecting and demodulating optical signals, and therefore is unable to receive the downstream control signal light. On the other hand, the downstream control signal light input to the wavelength multiplexing / demultiplexing unit 36-1 of the communication device 30-1 is output toward the control signal receiver 32-1. The control signal receiver 32-1 has the function of detecting and demodulating optical signals, and therefore is able to receive the downstream control signal light. In this way, in the communication device 30-1 that performs two-core transmission, the same downstream control signal light is input from two paths, and the communication device 30-1 receives the downstream control signal light input from one path.

[0145] Upon receiving the downstream control signal light, the communication device 30-1 transmits an upstream control signal from the control signal transmitter 31-1. The upstream control signal light transmitted from the control signal transmitter 31-1 is input to the port 11-1 of the optical node device 10a. The upstream control signal light input to the port 11-1 of the optical node device 10a is output to the control transceiver 13a-1 by the wavelength multiplexing / demultiplexing unit 12-1. The receiver 132 of the control transceiver 13a-1 receives the upstream control signal light. The receiver 132 of the control transceiver 13a-1 detects and demodulates the received upstream control signal light and outputs it to the control unit 20. Thereafter, the control unit 20 exchanges control signal light containing information necessary for authentication, registration, and optical path opening with the communication device 30-1 via the control transceiver 13a-1.

[0146] Assume that a user connects to the optical node device 10a by connecting one optical transmission path L to the communication device 30-2. As a result, as shown in Figure 6, assume that the wavelength multiplexing / demultiplexing unit 37-2 of the communication device 30-2 is connected to the port 11-4 of the optical node device 10a via the optical transmission path L.

[0147] However, the control unit 20 cannot determine which of the multiple ports 11 of the optical node device 10a the communication device 30-2 is connected to. After connecting to the optical node device 10a, the communication device 30-2 generates an upstream control signal including requests for authentication, registration, etc. The control signal transmitter 31-2 of the communication device 30-2 converts the generated upstream control signal into an optical signal and sends it out as upstream control signal light.

[0148] The upstream control signal light sent from the control signal transmitter 31-2 of the communication device 30-2 is input to port 11-4 of the optical node device 10a. The upstream control signal light input to port 11-4 is output by the wavelength multiplexing / demultiplexing unit 12-4 toward the control transceiver 13a-2. The wavelength multiplexing / demultiplexing unit 134 of the control transceiver 13a-2 outputs the upstream control signal light output from the wavelength multiplexing / demultiplexing unit 12-4 to the receiver 135. The receiver 135 detects and demodulates the upstream control signal light. The receiver 135 outputs the demodulated upstream control signal to the control unit 20 via a control line (not shown).

[0149] In response to receiving the upstream control signal, the control unit 20 recognizes that the new connection device has been connected to the optical node device 10a. Then, the control unit 20 identifies that the new connection device has been connected to the port 11 associated with the control transceiver 13a-2 that includes the receiver 135 that output the upstream control signal.

[0150] Alternatively, a light detector that detects light input to the port 11 may be provided for each port 11, and the control unit 20 may identify the port 11 to which the new connection device is connected based on the detection result of the light detector. In this case, the light detector that detects the input of light transmits port identification information to the control unit 20, including identification information for identifying the light detector and information indicating that the input of light has been detected (e.g., a light intensity value). The control unit 20 stores information correlating the identification information of the light detector with each port 11, thereby enabling the control unit 20 to identify the port 11 to which the light has been input based on the identification information of the light detector included in the port identification information. Note that the light detector may detect the optical input as either an upstream control signal light or a main signal light. In this case, the transmission of the upstream control signal light from the communication device 30-2 and the output of the upstream control signal from the control transceiver 13a-2 to the control unit 20 described above are not necessarily required. The new connection device may generate an upstream control signal required for authentication and registration after receiving the downstream control signal light described below, and output the upstream control signal from the control signal transmitter 31-2.

[0151] Thereafter, the control unit 20 transmits a transmission command including an instruction to transmit a downstream control signal to the control transceiver 13a-2 associated with the identified port 11. Note that the information as to which port 11 corresponds to which transmitter of the control transceiver 13a may be stored in advance.

[0152] The transmitters 133 and 136 included in the control transceiver 13a-2 transmit the same downstream control signal light (for example, wavelength λ １ The downstream control signal light transmitted from the transmitter 133 of the control transceiver 13a-1 is output from the port 11-3 via the wavelength multiplexing / demultiplexing unit 12-3. However, nothing is connected to the optical transmission line L connected to the port 11-3. Therefore, the downstream control signal light output from the port 11-3 is not received by any of the communication devices 30.

[0153] The downstream control signal light sent from the transmitter 136 of the control transceiver 13a-1 is output from port 11-4 via the wavelength multiplexing / demultiplexing unit 12-4 and input to the wavelength multiplexing / demultiplexing unit 37-2 of the communication device 30-2. The downstream control signal light input to the wavelength multiplexing / demultiplexing unit 37-2 is output to the control signal receiver 32-2. The control signal receiver 32-2 has the function of detecting and demodulating optical signals, and is therefore able to receive the downstream control signal light. In this way, in the communication device 30-2 that performs single-core bidirectional transmission, the downstream control signal light is input from one path and the input downstream control signal light is received.

[0154] Upon receiving the downstream control signal light, the communication device 30-2 transmits an upstream control signal from the control signal transmitter 31-2. The upstream control signal light transmitted from the control signal transmitter 31-2 is input to the port 11-4 of the optical node device 10a. The upstream control signal light input to the port 11-4 of the optical node device 10a is output to the control transceiver 13a-2 by the wavelength multiplexing / demultiplexing unit 12-4. The receiver 135 of the control transceiver 13a-2 receives the upstream control signal light. The receiver 135 of the control transceiver 13a-2 detects and demodulates the received upstream control signal light and outputs it to the control unit 20. Thereafter, the control unit 20 exchanges control signal light containing information necessary for authentication, registration, and optical path opening with the communication device 30-2 via the control transceiver 13a-2.

[0155] (Second Initial Connection Method in Second Embodiment) Next, a second initial connection method will be described. Assume that a user connects to the optical node device 10a by connecting two optical transmission paths L to the communication device 30-1. As a result, as shown in Fig. 6, the wavelength multiplexing / demultiplexing unit 35-1 of the communication device 30-1 is connected to port 11-1 of the optical node device 10a via the optical transmission paths L, and the wavelength multiplexing / demultiplexing unit 36-1 of the communication device 30-1 is connected to port 11-2 of the optical node device 10a via the optical transmission path L.

[0156] However, the control unit 20 cannot determine which of the multiple ports 11 of the optical node device 10a the communication device 30-1 is connected to. After connecting to the optical node device 10a, the communication device 30-1 generates an upstream control signal including type information. The control signal transmitter 31-1 of the communication device 30-1 converts the generated upstream control signal into an optical signal and sends it out as upstream control signal light.

[0157] The upstream control signal light sent from the control signal transmitter 31-1 of the communication device 30-1 is input to the port 11-1 of the optical node device 10a. The upstream control signal light input to the port 11-1 is output by the wavelength multiplexing / demultiplexing unit 12-1 toward the control transceiver 13a-1. The wavelength multiplexing / demultiplexing unit 131 of the control transceiver 13a-1 outputs the upstream control signal light output from the wavelength multiplexing / demultiplexing unit 12-1 to the receiver 132. The receiver 132 detects and demodulates the upstream control signal light. The receiver 132 outputs the demodulated upstream control signal to the control unit 20 via a control line (not shown).

[0158] In response to receiving the upstream control signal, the control unit 20 recognizes that a new connection device has been connected to the optical node device 10a. Furthermore, the control unit 20 recognizes that the communication device 30-1 is a communication device that performs two-core transmission based on the type information included in the upstream control signal. The control unit 20 also identifies that the new connection device has been connected to the port 11-1 associated with the control transceiver 13a-1 that includes the receiver 132 that output the upstream control signal.

[0159] When the communication device 30-1 performs two-core transmission, the optical transmission path L used for transmission is different from the optical transmission path L used for reception. Therefore, the transmission port of the communication device 30-1 is connected to the port 11-1 to which the upstream control signal light is input. Therefore, the control unit 20 can recognize that the identified port 11-1 is connected to the transmission port of the newly connected device.

[0160] Alternatively, a light detector that detects light input to the port 11 may be provided for each port 11, and the control unit 20 may identify the port 11 to which the newly connected device is connected based on the detection result of the light detector. In this case, the light detector that detects the input of light transmits port identification information to the control unit 20, the port identification information including identification information for identifying the light detector and information indicating that the input of light has been detected (e.g., a value of light intensity). The control unit 20 stores information that associates the identification information of the light detector with each port 11, and thereby can identify the port 11 to which light has been input based on the identification information of the light detector included in the port identification information. Note that the target of the optical input detected by the light detector may be upstream control signal light or main signal light.

[0161] Thereafter, the control unit 20 refers to the port management information and identifies the port 11-2 registered as a pair with the identified port 11-1. A pair of ports 11 are connected to the transmitting port and receiving port of the communication device 30-1 via the optical transmission path L. Therefore, the receiving port of the communication device 30-1 is connected to the port 11-2 registered as a pair with the port 11-1. Therefore, the control unit 20 causes the transmitter 136 of the control transceiver 13a-1 corresponding to the identified port 11-2 to transmit a downstream control signal light. Note that information regarding which port 11 corresponds to which transmitter of the control transceiver 13a may be stored in advance. As a result, the control unit 20 exchanges control signal light with the communication device 30-1, including information necessary for authentication, registration, and optical path opening.

[0162] Next, suppose that the user connects to the optical node device 10a by connecting one optical transmission path L to the communication device 30-2. As a result, suppose that the wavelength multiplexing / demultiplexing unit 37-2 of the communication device 30-2 is connected to the port 11-4 of the optical node device 10a via the optical transmission path L, as shown in FIG.

[0163] However, the control unit 20 cannot determine which of the multiple ports 11 of the optical node device 10a the communication device 30-2 is connected to. After connecting to the optical node device 10a, the communication device 30-2 generates an upstream control signal including type information. The control signal transmitter 31-2 of the communication device 30-2 converts the generated upstream control signal into an optical signal and sends it out as upstream control signal light.

[0164] The upstream control signal light sent from the control signal transmitter 31-2 of the communication device 30-2 is input to port 11-4 of the optical node device 10a. The upstream control signal light input to port 11-4 is output by the wavelength multiplexing / demultiplexing unit 12-4 toward the control transceiver 13a-2. The wavelength multiplexing / demultiplexing unit 134 of the control transceiver 13a-2 outputs the upstream control signal light output from the wavelength multiplexing / demultiplexing unit 12-4 to the receiver 135. The receiver 135 detects and demodulates the upstream control signal light. The receiver 135 outputs the demodulated upstream control signal to the control unit 20 via a control line (not shown).

[0165] In response to receiving the upstream control signal, the control unit 20 recognizes that a new connection device has been connected to the optical node device 10a. Furthermore, the control unit 20 recognizes that the communication device 30-2 is a communication device that performs single-core bidirectional transmission based on the type information included in the upstream control signal. The control unit 20 also identifies that the new connection device has been connected to the port 11-4 associated with the control transceiver 13a-2 that includes the receiver 135 that output the upstream control signal.

[0166] Alternatively, a light detector that detects light input to the port 11 may be provided for each port 11, and the control unit 20 may identify the port 11 to which the newly connected device is connected based on the detection result of the light detector. In this case, the light detector that detects the input of light transmits port identification information to the control unit 20, the port identification information including identification information for identifying the light detector and information indicating that the input of light has been detected (e.g., a value of light intensity). The control unit 20 stores information that associates the identification information of the light detector with each port 11, and thereby can identify the port 11 to which light has been input based on the identification information of the light detector included in the port identification information. Note that the target of the optical input detected by the light detector may be upstream control signal light or main signal light.

[0167] When the communication device 30-2 performs single-core bidirectional transmission, the optical transmission path L used for transmission and the optical transmission path L used for reception are the same. Therefore, the control unit 20 causes the transmitter 136 of the control transceiver 13a-2 corresponding to the identified port 11-4 to transmit a downstream control signal light. As a result, the control unit 20 exchanges control signal light containing information necessary for authentication, registration, and optical path opening with the communication device 30-2.

[0168] According to the optical communication system 100a configured as above, it is possible to obtain the same effects as those of the first embodiment.

[0169] Furthermore, in the optical communication system 100a, the optical node device 10a includes one control transceiver 13a having two pairs of transceivers capable of single-core bidirectional transmission for each pair of ports 11. This eliminates the need to provide an individual control transceiver for each port 11, as in the first embodiment.

[0170] Some of the functional units of the control unit 20 in the above-described embodiment may be implemented by a computer. In this case, a program for implementing the functions may be recorded on a computer-readable recording medium, and the program recorded on the recording medium may be read into a computer system and executed. Note that the term "computer system" here includes hardware such as an OS (Operating System) and peripheral devices.

[0171] Furthermore, "computer-readable recording media" refers to portable media such as flexible disks, optical magnetic disks, ROMs (Read Only Memory), and CD-ROMs, as well as storage devices such as hard disks built into computer systems. Furthermore, "computer-readable recording media" may also include devices that dynamically store programs for a short period of time, such as communication lines used when transmitting programs over networks like the Internet or communication lines like telephone lines, or devices that store programs for a fixed period of time, such as volatile memory within the computer systems that serve as servers or clients. Furthermore, the programs may be designed to realize some of the aforementioned functions, or may be capable of realizing the aforementioned functions in combination with programs already stored in the computer system, or may be realized using programmable logic devices such as FPGAs (Field Programmable Gate Arrays).

[0172] Although an embodiment of the present invention has been described above in detail with reference to the drawings, the specific configuration is not limited to this embodiment, and includes designs within the scope of the gist of the present invention.

[0173] The present invention can be applied to a technique for opening an optical path.

[0174] 10, 10a... Optical node device, 11, 11-1 to 11-6... Port, 12, 12-1 to 12-6, 35, 35-1, 36, 36-1, 37, 37-2 to 37-3, 131... Wavelength multiplexing / demultiplexing unit, 13, 13-1 to 13-6, 13a... Control transceiver, 20... Control unit, 30... Communication device, 31, 31-1 to 31-3... Control signal transmitter, 32, 32-1 to 32-3... Control signal receiver, 33, 33-1 to 33-3... Main signal transmitter, 34, 34-1 to 34-3... Main signal receiver, 100, 100a... Optical communication system, 132... Receiver, 133... Transmitter

Claims

1. An optical node device provided between one or more communication devices that perform single-core bidirectional transmission or dual-core transmission and a control device that controls the one or more communication devices, comprising: a plurality of ports to which the one or more communication devices are connected; and one or more transceivers that are connected to at least one port via at least one first wavelength multiplexing / demultiplexing unit that multiplexes or demultiplexes input optical signals, and that transmit and receive control signal light to and from the one or more communication devices, wherein the one or more transceivers comprise: one or more receivers that receive upstream control signal light transmitted from the one or more communication devices and output it to the control device; one or more transmitters that transmit downstream control signal light addressed to the one or more communication devices; and one or more second wavelength multiplexing / demultiplexing units that output the upstream control signal light input via at least one connected first wavelength multiplexing / demultiplexing unit to the one or more receivers, and output the downstream control signal light transmitted from the one or more transmitters to at least one connected first wavelength multiplexing / demultiplexing unit.

2. The optical node device according to claim 1, wherein, when the one or more communication devices are newly connected, two transceivers connected to one or more ports among the plurality of ports via different first wavelength multiplexing / demultiplexing units transmit the same downstream control signal light.

3. The optical node device according to claim 2, wherein the two transceivers are a transceiver that connects via a first wavelength multiplexing / demultiplexing unit to a first port among the plurality of ports that is identified as the port to which the one or more newly connected communication devices will connect, and a transceiver that connects via a first wavelength multiplexing / demultiplexing unit to a second port that is registered as a pair with the first port.

4. The optical node device of claim 1, wherein the one or more transceivers each include a plurality of the one or more receivers, the one or more transmitters, and the one or more second wavelength multiplexers / demultiplexers, and when the one or more communication devices are newly connected, the plurality of transmitters included in one transceiver connected through a first wavelength multiplexer / demultiplexer different from each of the one or more ports to which the one or more newly connected communication devices are connected among the plurality of ports transmit the same downstream control signal light.

5. The optical node device according to claim 1, wherein, when the one or more newly connected communication devices are communication devices that perform two-core transmission, the one or more transceivers transmit the downstream control signal light to the one or more newly connected communication devices from a port that is registered as a pair with a port to which the upstream control signal light transmitted from the one or more newly connected communication devices is input.

6. An optical node device as described in claim 1 or 5, wherein, when the one or more newly connected communication devices are communication devices that perform single-core bidirectional transmission, the one or more transceivers send out the downstream control signal light from a port to which the upstream control signal light transmitted from the one or more newly connected communication devices is input, toward the one or more newly connected communication devices.

7. The optical node device according to claim 1, wherein the one or more transceivers each include a plurality of the one or more receivers, one or more transmitters, and one or more second wavelength multiplexers / demultiplexers, and when the newly connected one or more communication devices are communication devices performing two-core transmission, the one or more transceivers send out the downstream control signal light to the one or more newly connected communication devices from a transmitter corresponding to a port registered as a pair with a port into which the upstream control signal light transmitted from the one or more newly connected communication devices is input, and when the newly connected one or more communication devices are communication devices performing single-core bidirectional transmission, the one or more transceivers send out the downstream control signal light to the one or more newly connected communication devices from a transmitter corresponding to a port into which the upstream control signal light transmitted from the one or more newly connected communication devices is input.

8. A connection method performed by an optical node device provided between one or more communication devices that perform single-core bidirectional transmission or dual-core transmission and a control device that controls said one or more communication devices, wherein one or more transceivers that are connected to at least one port out of multiple ports to which said one or more communication devices are connected via at least one first wavelength multiplexing / demultiplexing unit that multiplexes or demultiplexes input optical signals and that transmit and receive control signal light to said one or more communication devices receive upstream control signal light transmitted from said one or more communication devices and output it to said control device, send downstream control signal light addressed to said one or more communication devices, receive said upstream control signal light input via at least one first wavelength multiplexing / demultiplexing unit connected to said at least one port and output it to said control device, and output said sent downstream control signal light to at least one first wavelength multiplexing / demultiplexing unit connected to said at least one port.

Images