Optical node device, transceiver, and connection method

Abstract

This optical node device comprises: a plurality of ports to which one or more communication devices connect; and one or more transceivers that are connected to at least one port via at least one first wavelength multiplexing / demultiplexing unit for multiplexing or demultiplexing inputted optical signals, and that transmit and receive control signal light to and from the one or more communication devices. The one or more transceivers comprise: one or more timing control units that, when the one or more communication devices are communication devices that perform single-core bidirectional transmission, adjust the control signal transmission timing to the one or more communication devices; one or more transmitters that, when the one or more communication devices are communication devices that perform single-core bidirectional transmission, transmit downlink control signal light addressed to the one or more communication devices at the transmission timing adjusted by the one or more timing control units; and one or more second wavelength multiplexing / demultiplexing waves that output downlink control signal light transmitted from the one or more transmitters to the at least one first wavelength multiplexing / demultiplexing unit that is connected.　

Description

Optical node device, transceiver and connection method

[0001] The present invention relates to an optical node device, a transceiver, 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 5 and 6 are diagrams for explaining a method of opening an optical path in a conventional optical communication system S. As shown in Figure 5, 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 6. 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 6.

[0007] International Publication No. 2021 / 131202

[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] 7 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. 7 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. 7, 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. 7, 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. 7, 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] 7, for example, 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] 7, 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. That is, in the conventional control signal light transmission / reception configuration shown in FIG. 7, there was a problem in that the communication device 200 performing single-core bidirectional transmission was unable to exchange control signals with the control unit 400. There was a problem in that control signals could not be exchanged between the communication device 200 and the control unit 400.

[0017] In view of the above circumstances, an object of the present invention is to provide a technique 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 that are 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, wherein the one or more transceivers comprise: one or more timing control units that, when the one or more communication devices are communication devices that perform single-core bidirectional transmission, adjust the transmission timing of control signals between the one or more communication devices; one or more transmitters that, when the one or more communication devices are communication devices that perform single-core bidirectional transmission, send downstream control signal light addressed to the one or more communication devices at the transmission timing adjusted by the one or more timing control units; and one or more second wavelength multiplexing / demultiplexing units that output the downstream control signal light sent from the one or more transmitters to at least one of the first wavelength multiplexing / demultiplexing units connected thereto.

[0019] One aspect of the present invention is a transceiver comprising: one or more timing control units that adjust the transmission timing of control signals between one or more connected communication devices when the one or more connected communication devices are communication devices that perform single-core bidirectional transmission; one or more transmitters that send downstream control signal light addressed to the one or more communication devices at the transmission timing adjusted by the one or more timing control units when the one or more connected communication devices are communication devices that perform single-core bidirectional transmission; and one or more second wavelength multiplexing / demultiplexing units that output the downstream control signal light sent from the one or more transmitters to a first wavelength multiplexing / demultiplexing unit to which the one or more communication devices are connected.

[0020] 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 and from the one or more communication devices adjust the transmission timing of the control signal between the one or more communication devices when the one or more communication devices are communication devices that perform single-core bidirectional transmission, and send downstream control signal light addressed to the one or more communication devices at the adjusted transmission timing when the one or more communication devices are communication devices that perform single-core bidirectional transmission, and output the downstream control signal light sent from the one or more transmitters to at least one first wavelength multiplexing / demultiplexing unit connected thereto.

[0021] According to the present invention, it is possible to exchange signals with the control unit regardless of the type of transmission method used by the communication device.

[0022] FIG. 1 is a diagram illustrating a configuration example of an optical communication system in a first embodiment. FIG. 2 is a diagram for explaining an initial connection method performed by the optical communication system in the first embodiment. FIG. 3 is a sequence diagram illustrating a processing flow of the initial connection method performed by the optical communication system in the first embodiment. FIG. 4 is a diagram illustrating a configuration example of an optical communication system in a second embodiment. FIG. 5 is a diagram for explaining a method of opening an optical path in a conventional optical communication system. FIG. 6 is a diagram for explaining a method of opening an optical path in a conventional optical communication system. FIG. 7 is a diagram for explaining a problem in a conventional optical communication system.

[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, 40 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, 40 are connected to the optical node device 10 via the optical transmission path L, but the number of communication devices 30, 40 may be one or more.

[0024] In the optical communication system 100, the communication device 30 is a device that performs two-core transmission, and the communication devices 40-1 and 40-2 are devices that perform single-core bidirectional transmission. The communication device 30 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 40-1 and 40-2 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. 5. 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 another optical node device or communication device via an optical transmission path L at a port different from the port to which one communication device 30, 40 is connected. The same applies to the following embodiments.

[0026] In the following description, the direction from the communication devices 30, 40 toward the control unit 20 is referred to as the upstream direction, and the direction from the control unit 20 toward the communication devices 30, 40 is referred to as the downstream direction. The number of optical node devices 10 is not particularly limited.

[0027] [Configuration of Optical Node Device 10] The optical node device 10 is a node device that constitutes a wavelength network, and accommodates one or more communication devices 30, 40. 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 of the communication devices 30, 40. 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, 40 are connected to the multiple ports 11 via optical transmission lines L. The communication device 30 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 is connected to ports 11-1 and 11-2 via two optical transmission lines L.

[0029] The communication devices 40-1 and 40-2 are devices that perform single-core bidirectional transmission, and are therefore connected to one port 11 via one optical transmission path L. In the example shown in FIG. 1, the communication device 40-1 is connected to port 11-4 via one optical transmission path L. The communication device 40-2 is connected to port 11-5 via one optical transmission path L. Note that each of the communication devices 30 and 40 may be connected to any of the ports 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 devices 30 and 40. 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 devices 30 and 40 that are the source and destination of the optical signals.

[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 devices 30 and 40. 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 devices 30 and 40.

[0035] The control transceiver 13 is a single-core bidirectional transmission type transceiver. A single-core bidirectional transmission type transceiver is a transceiver that can transmit and receive optical signals via a single optical transmission line L. The control transceiver 13 communicates with the communication device 30 that performs dual-core transmission using continuous light. In other words, the control transceiver 13 transmits downstream control signal light using continuous light to the communication device 30 that performs dual-core transmission.

[0036] The control transceiver 13 communicates with the communication device 40 that performs single-fiber bidirectional transmission using time division multiplexing. That is, the control transceiver 13 transmits downstream control signal light as burst light to the communication device 30 that performs single-fiber bidirectional transmission. In this way, the control transceiver 13 communicates with the communication device 40 that performs single-fiber bidirectional transmission by adjusting the transmission time so that the timing when the communication device 40 transmits a control signal and the timing when the control transceiver 13 transmits a control signal do not overlap.

[0037] The control transceiver 13-m includes a wavelength multiplexer / demultiplexer 131, a receiver 132, a transmitter 133, and a timing controller .

[0038] 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.

[0039] 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.

[0040] 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.

[0041] The transmitter 133 transmits downstream control signal light at a predetermined wavelength. The transmitter 133 transmits downstream control signal light to each of the communication device 30 performing two-core transmission and the communication device 40 performing single-core bidirectional transmission. When the transmitter 133 transmits downstream control signal light to the communication device 30 performing two-core transmission, the downstream control signal light is transmitted via a path different from the upstream control signal light transmitted by the communication device 30. Therefore, the transmitter 133 only needs to transmit the downstream control signal light to the communication device 30 at the timing when the control signal is obtained from the control unit 20.

[0042] However, when the transmitter 133 transmits downstream control signal light to the communication device 40 performing single-fiber bidirectional transmission, the downstream control signal light is transmitted via the same path as the upstream control signal light transmitted by the communication device 40. Therefore, the control transceiver 13 connected to the communication device 40 performing single-fiber bidirectional transmission determines in advance the timing of transmitting a control signal between the control transceiver 13 and the communication device 40. For example, the control transceiver 13 determines a timing that does not collide with the timing of the communication device 40 transmitting the upstream control signal light (a timing different from the timing of the communication device 40 transmitting the upstream control signal light).

[0043] The transmitter 133 sends downstream control signal light of a predetermined wavelength to the first port of the wavelength multiplexing / demultiplexing unit 131 at the transmission timing set by the timing control unit 134. As a result, the downstream control signal light sent by the transmitter 133 and the upstream control signal light sent by the communication device 40 are sent at different timings. Since the optical node device 10 and the communication device 40 communicate using time division multiplexing, the control signal transmitter 41 sends upstream control signal light at a predetermined wavelength at a timing when the optical node device 10 is not sending a control signal.

[0044] When a communication device 40 performing single-core bidirectional transmission is connected to the optical node device 10, the timing control unit 134 adjusts the transmission timing of control signals between the communication device 40 and the optical node device 10. For example, the timing control unit 134 adjusts the transmission timing of each control signal so that the time period in which the control transceiver 13 transmits downstream control signal light and the time period in which the communication device 40 transmits upstream control signal light do not overlap. The timing control unit 134 causes the transmitter 133 to transmit downstream control signal light at the adjusted transmission timing. For example, the timing control unit 134 causes the transmitter 133 to transmit downstream control signal light during a time period in which the optical node device 10 is able to transmit control signals.

[0045] In addition, whether the communication device connected to the optical node device 10 is a communication device that performs single-core bidirectional transmission or a communication device that performs two-core transmission can be determined by a declaration from the communication device connected to the optical node device 10.

[0046] 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.

[0047] 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.

[0048] The wavelength of the upstream control signal light output to the control transceiver 13 may be common to the communication device 30 that performs two-core transmission and the communication devices 40-1 and 40-2 that perform single-core bidirectional transmission. In the first embodiment, regardless of the type of transmission method of the communication devices 30 and 40, the wavelength of the downstream control signal light transmitted by the control transceiver 13 is set to λ１ and the wavelength of the upstream control signal light transmitted by the communication device 30 is λ １ It states that:

[0049] [Configuration of the control unit 20] The control unit 20 controls the optical node device 10 and the communication devices 30 and 40. 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 devices 30 and 40 includes, for example, processing such as authentication and registration with a new connecting device, allocation of emission wavelengths to the communication devices 30 and 40, instructions to stop light and to change wavelengths, etc.

[0050] The control unit 20 performs the above-mentioned control on the communication devices 30, 40 (including, for example, communication devices 30, 40 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, 40 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.

[0051] 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.

[0052] The control unit 20 also holds port management information related to the ports of the optical node device 10 to which each of the communication devices 30, 40 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.

[0053] [Configuration of communication device 30 performing two-core transmission] The communication device 30 performs two-core transmission and 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.

[0054] 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.

[0055] 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 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.

[0056] 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 performing two-core transmission may be assigned a wavelength λ ２is assigned to the .

[0057] 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.

[0058] 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.

[0059] 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, when 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 performing two-core transmission and the optical node device 10.

[0060] 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.

[0061] [Configuration of communication device 40 performing single-fiber bidirectional transmission] The communication device 40 performs single-fiber bidirectional transmission. The communication device 40 performing single-fiber bidirectional transmission includes a control signal transmitter 41, a control signal receiver 42, a main signal transmitter 43, a main signal receiver 44, a wavelength multiplexing / demultiplexing unit 45, and a timing control unit 46.

[0062] The control signal transmitter 41 is a transmitter used to transmit control signals. The control signal transmitter 41 transmits upstream control signal light at a predetermined wavelength at a transmission timing instructed by the timing control unit 46. Since the communication device 40 and the optical node device 10 communicate by time division multiplexing, the control signal transmitter 41 transmits upstream control signal light at a predetermined wavelength at a timing when the optical node device 10 is not transmitting a control signal.

[0063] The control signal receiver 42 is a receiver used to receive control signals. The control signal receiver 42 receives downstream control signal light transmitted from the optical node device 10. Since the communication device 40 and the optical node device 10 communicate using time division multiplexing, the control signal receiver 42 receives downstream control signal light at a timing when the control signal transmitter 41 does not transmit upstream control signals. The control signal receiver 42 has the function of detecting and demodulating optical signals.

[0064] Here, the communication devices 40-1 and 40-2 have wavelengths λ 1 as the transmission wavelength and reception wavelength of the control signal. １ The timing control unit 46 provided in the communication device 40 that performs single-core bidirectional transmission and the timing control unit 134 provided in the control transceiver 13 adjust the transmission times of the upstream control signal and the downstream control signal, thereby realizing single-core bidirectional transmission of the control signal by time division multiplexing.

[0065] The main signal transmitter 43 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 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.

[0066] The wavelength of the main signal light transmitted by the main signal transmitter 43 provided in the communication devices 40-1 and 40-2 may be assigned to the communication devices 40 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.

[0067] In addition, the communication devices 40-1 and 40-2 generally need to perform wavelength multiplexing by changing the transmission wavelength and the reception wavelength, or time division multiplexing so that the transmission times of the transmission wavelength and the reception wavelength do not overlap. As an example, the communication device 40-1 has a transmission wavelength of λ ３ is assigned, and the receiving wavelength λ ３ In addition, as an example, the communication device 40-2 is assigned a wavelength λ ４ is assigned, and the receiving wavelength λ ４ In this way, the main signal is transmitted bidirectionally over a single fiber by wavelength multiplexing.

[0068] The wavelength multiplexing / demultiplexing unit 45 is connected to a transmission / reception port of the communication device 40. The transmission / reception port is a port used for both transmitting and receiving optical signals. The wavelength multiplexing / demultiplexing unit 45 wavelength-multiplexes the upstream control signal light sent from the control signal transmitter 41 and the main signal light sent from the main signal transmitter 43, and outputs the multiplexed signal light from the transmission / reception port toward the optical node device 10. The wavelength multiplexing / demultiplexing unit 45 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 side. The wavelength multiplexing / demultiplexing unit 45 outputs the separated downstream control signal light to the control signal receiver 42, and outputs the separated main signal light to the main signal receiver 44.

[0069] When connected to the optical node device 10, the timing control unit 46 adjusts the transmission timing of control signals between the optical node device 10 and the optical node device 10. For example, the timing control unit 46 adjusts the transmission timing of each control signal so that the time period in which the control transceiver 13 transmits downstream control signal light and the time period in which the communication device 40 transmits upstream control signal light do not overlap. The timing control unit 46 causes the control signal transmitter 41 to transmit upstream control signal light at the adjusted transmission timing. For example, the timing control unit 46 causes the control signal transmitter 41 to transmit upstream control signal light during the time period in which the communication device 40 is able to transmit control signals.

[0070] When connecting a communication device 40 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 40.

[0071] When a communication device 30, 40 before an optical path is opened is newly connected to the optical node device 10, it exchanges information necessary for registration and authentication and for opening an optical path with the control unit 20. The information necessary for opening an optical path includes, for example, information on the wavelength used for transmission and reception, and information indicating the communication device to be communicated with. The communication device 30, 40 may output an 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, 40 is, for example, an ONU (Optical Network Unit) installed in a subscriber's premises.

[0072] 1, the communication device 30 performing dual-core transmission can transmit an upstream control signal optical signal from the control signal transmitter 31 toward one control transceiver 13 (e.g., control transceiver 13-1), and can receive a downstream control signal optical signal transmitted from another control transceiver 13 (e.g., control transceiver 13-2) at the control signal receiver 32. In other words, the communication device 30 performing dual-core transmission can exchange control signals with the control unit 20 using two control transceivers 13.

[0073] In addition, communication devices 40-1 and 40-2 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 using time division multiplexing 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 the communication device 30 that performs two-core transmission.

[0074] (Initial Connection Method) Next, an initial connection method in which the control unit 20 performs authentication and registration processing on a newly connected device when a new communication device 30, 40 is connected to the optical node device 10 will be described with reference to FIG.

[0075] (Initial Connection Method) In the first embodiment, the initial connection method is a method in which a new connection device declares 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. 2 is a diagram for explaining the initial connection method performed by the optical communication system 100 in the first embodiment.

[0076] 2 shows a case where a communication device 30 performing two-core transmission and communication devices 40-1 and 40-2 performing single-core bidirectional transmission are newly connected to the optical node device 10. In explaining the 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.

[0077] First, assume that a communication device 30 performing two-core transmission is newly connected to the optical node device 10. For example, assume that the communication device 30 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 performing two-core transmission is connected to the optical node device 10, the control signal transmitter 31 of the communication device 30 converts an upstream control signal including 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.

[0078] The upstream control signal light sent from the communication device 30 is input to port 11-1 of the optical node device 10. The control transceiver 13-1 connected to 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. 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 is a communication device that performs two-core transmission based on the type information included in the upstream control signal.

[0079] When the communication device 30 is a communication device that performs two-core transmission, the control unit 20 refers to the port management information and identifies the port 11 that is registered as a pair with the port 11-1 that is connected to the control transceiver 13-1 that received the upstream control signal light via the wavelength multiplexing / demultiplexing unit 12-1. Then, the control unit 20 causes the control transceiver 13-2 that 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. This allows the communication device 30 that 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.

[0080] 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 is connected via the wavelength multiplexing / demultiplexing unit 12-1.

[0081] Next, suppose that a communication device 40-1 performing single-fiber bidirectional transmission is newly connected to the optical node device 10. For example, suppose that the communication device 40-1 is connected to port 11-4 of the optical node device 10 via an optical transmission path L. When the communication device 40-1 performing single-fiber bidirectional transmission is connected to the optical node device 10, the control signal transmitter 41-1 of the communication device 40-1 converts an upstream control signal including 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.

[0082] The upstream control signal light sent from the communication device 40-1 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 40-1 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 40-1, regardless of which port 11 the communication device 40-1 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 40-1 is a communication device performing single-fiber bidirectional transmission based on the type information included in the upstream control signal.

[0083] When the communication device 40-1 is a communication device that performs single-core bidirectional transmission, the control unit 20 notifies the control transceiver 13-4 to which the communication device 40-1 is connected that the communication device performs single-core bidirectional transmission. As a result, the control transceiver 13-4 can determine that the connected communication device is a communication device that performs single-core bidirectional transmission. This allows the timing control unit 46-1 of the communication device 40-1 and the timing control unit 134 of the control transceiver 13 to adjust the transmission timing of control signals between them. This enables single-core bidirectional communication of control signals using time division multiplexing.

[0084] As a result, the communication device 40-1 that performs single-core bidirectional transmission can 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 that used for communication with the communication device 30 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.

[0085] 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 40-1 is connected.

[0086] Furthermore, when the optical node device 10 determines from a report from the communication device 40-1 that the communication device 40-1 is a communication device that performs single-fiber 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 40-1 is connected. In this case, since the port 11-3 whose pair has been canceled remains unused, the control unit 20 may use it as the port 11 to which a newly connected communication device 40 that performs single-fiber bidirectional transmission is to be connected later.

[0087] Although not shown in FIG. 2, the main signal transmitter 43 in the communication device 40 may emit light during the procedure of the above-described initial connection method.

[0088] In the above-described initial connection method, 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.

[0089] 3 is a sequence diagram showing the processing flow of the initial connection method performed by the optical communication system 100 in the first embodiment. Assume that a user connects to the optical node device 10 by connecting two optical transmission paths L to the communication device 30 (step S101). As a result, as shown in FIG. 2, assume that the wavelength multiplexing / demultiplexing unit 35 of the communication device 30 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 ​​of the communication device 30 is connected to port 11-2 of the optical node device 10 via the optical transmission path L.

[0090] However, the control unit 20 cannot determine which of the multiple ports 11 of the optical node device 10 the communication device 30 is connected to. After connecting to the optical node device 10, the communication device 30 generates an upstream control signal including type information. The control signal transmitter 31-1 of the communication device 30 converts the generated upstream control signal into an optical signal and sends it out as upstream control signal light (step S102).

[0091] The upstream control signal light sent from the control signal transmitter 31-1 of the communication device 30 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).

[0092] 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 is a communication device that performs two-core transmission based on the type information included in the upstream control signal (step S104). 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.

[0093] When the communication device 30 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 port 11-1 to which the upstream control signal light is input is connected to the transmission port of the communication device 30. Therefore, the control unit 20 can recognize that the identified port 11-1 is connected to the transmission port of the newly connected device.

[0094] 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.

[0095] 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 via the optical transmission path L. Therefore, the receiving port of the communication device 30 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 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, including information necessary for authentication, registration, and optical path opening (step S105).

[0096] Next, it is assumed that the user connects one optical transmission line L to the communication device 40-1 to connect to the optical node device 10 (step S106). As a result, it is assumed that the wavelength multiplexing / demultiplexing unit 45-1 of the communication device 40-1 is connected to the port 11-4 of the optical node device 10 via the optical transmission line L, as shown in FIG.

[0097] However, the control unit 20 cannot determine which of the multiple ports 11 of the optical node device 10 the communication device 40-1 is connected to. After connecting to the optical node device 10, the communication device 40-1 generates an upstream control signal including type information. The control signal transmitter 41-1 of the communication device 40-1 converts the generated upstream control signal into an optical signal and sends it out as upstream control signal light (step S107).

[0098] The upstream control signal light sent from the control signal transmitter 41-1 of the communication device 40-1 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 S108).

[0099] 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 40-1 is a communication device that performs single-core bidirectional transmission (step S109). 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.

[0100] 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.

[0101] When the communication device 40-1 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. The control unit 20 outputs the downstream control signal, which includes type information, to the control transceiver 13-4 (step S110).

[0102] The timing control unit 134 of the control transceiver 13-4 determines, based on the type information included in the downstream control signal output from the control unit 20, that the connected communication device is a communication device 40 performing single-core bidirectional transmission. The timing control unit 134 adjusts the transmission time (transmission timing) of the control signal with the communication device 40-1 (step S110). The timing control unit 134 causes the transmitter 133 to transmit the downstream control signal output from the control unit 20 during the transmission time period determined by the adjustment. 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 40-1 via the optical node device 10 using time division multiplexing (step S111). Note that control signals other than information necessary for optical path opening are also exchanged between the optical node device 10 and the communication device 40-1 using time division multiplexing.

[0103] 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, 40. Each control transceiver 13 includes a timing control unit 134 that adjusts the transmission timing of a control signal with the communication device 40 when the communication device is the communication device 40 that performs single-core bidirectional transmission, a transmitter 133 that sends downstream control signal light addressed to the communication device 40 at the transmission timing adjusted by the timing control unit 134 when the communication device is the communication device 40 that performs single-core bidirectional transmission, and a wavelength multiplexing / demultiplexing unit 131 that outputs the downstream control signal light sent from the transmitter 133 to the connected wavelength multiplexing / demultiplexing unit 12.

[0104] 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, regardless of whether the upstream control signal light is transmitted from a communication device 30 performing two-fiber transmission or a communication device 30 performing single-fiber bidirectional transmission. Furthermore, when a communication device 40 performing single-fiber bidirectional transmission is connected, the optical node device 10 adjusts the transmission timing of the control signals to prevent the upstream control signal light and the downstream control signal light from being transmitted at the same time. This allows the optical node device 10 to avoid collisions between the upstream and downstream control signals. Therefore, control signals can 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 devices 30 and 40.

[0105] 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.

[0106] 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.

[0107] 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.

[0108] Fig. 4 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, 40 are connected to the optical node device 10a via an optical transmission path L. In the example shown in Fig. 4, three communication devices 30, 40 are connected to the optical node device 10a via the optical transmission path L, but the number of communication devices 30, 40 may be one or more. In the optical communication system 100a, the communication device 30 is a device that performs two-core transmission, and the communication devices 40-1, 40-2 are devices that perform single-core bidirectional transmission.

[0109] The optical node device 10a is a node device that constitutes a wavelength network and accommodates one or more communication devices 30, 40. 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. 4 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 devices 30, 40. However, the optical node device 10a also includes a forwarding function for forwarding optical signals to other optical node devices or communication devices.

[0110] 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.

[0111] 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.

[0112] 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.

[0113] 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.

[0114] The control transceiver 13a includes a wavelength multiplexing / demultiplexing unit 131, a receiver 132, a transmitter 133, a timing control unit 134, a wavelength multiplexing / demultiplexing unit 135, a receiver 136, a transmitter 137, and a timing control unit 138. The wavelength multiplexing / demultiplexing unit 131, the receiver 132, the transmitter 133, and the timing control unit 134 are used to transmit and receive optical signals at one port 11. The wavelength multiplexing / demultiplexing unit 135, the receiver 136, the transmitter 137, and the timing control unit 138 are used to transmit and receive optical signals at the other port 11 that is paired with the other port 11.

[0115] Therefore, when the connected communication device is the communication device 40 that performs single-core bidirectional transmission, the timing control unit 134 controls the transmission timing of the downstream control signal light in the transmitter 133. When the connected communication device is the communication device 40 that performs single-core bidirectional transmission, the timing control unit 138 controls the transmission timing of the downstream control signal light in the transmitter 137.

[0116] 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, receiver 132, transmitter 133, and timing control unit 134 are used to transmit and receive optical signals at port 11-1, while the wavelength multiplexing / demultiplexing unit 135, receiver 136, transmitter 137, and timing control unit 138 are used to transmit and receive optical signals at port 11-2.

[0117] In this way, the control transceiver 13a includes two pairs of combinations of a wavelength multiplexing / demultiplexing unit, a transmitter, a receiver, and a timing control unit. The control unit 20 may store information indicating which port 11 each combination of a wavelength multiplexing / demultiplexing unit, a transmitter, a receiver, and a timing control unit 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, a transmitter 133, and a timing control unit 134 corresponds to port 11-1, and the combination of a wavelength multiplexing / demultiplexing unit 135, a receiver 136, a transmitter 137, and a timing control unit 138 corresponds to port 11-2.

[0118] The above example is merely an example, and the combination of two pairs of wavelength multiplexing / demultiplexing units, receivers, transmitters, and timing control units 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.

[0119] 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 will be shown below.

[0120] (Initial Connection Method in Second Embodiment) It is assumed that a user connects to the optical node device 10a by connecting two optical transmission paths L to the communication device 30. As a result, as shown in Fig. 4, it is assumed that the wavelength multiplexing / demultiplexing unit 35 of the communication device 30 is connected to port 11-1 of the optical node device 10a via the optical transmission path L, and the wavelength multiplexing / demultiplexing unit 36 ​​of the communication device 30 is connected to port 11-2 of the optical node device 10a via the optical transmission path L.

[0121] However, the control unit 20 cannot determine which of the multiple ports 11 of the optical node device 10a the communication device 30 is connected to. After connecting to the optical node device 10a, the communication device 30 generates an upstream control signal including type information. The control signal transmitter 31 of the communication device 30 converts the generated upstream control signal into an optical signal and sends it out as upstream control signal light.

[0122] The upstream control signal light sent from the control signal transmitter 31 of the communication device 30 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).

[0123] 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. Furthermore, the control unit 20 recognizes that the communication device 30 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.

[0124] When the communication device 30 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 port 11-1 to which the upstream control signal light is input is connected to the transmission port of the communication device 30. Therefore, the control unit 20 can recognize that the identified port 11-1 is connected to the transmission port of the newly connected device.

[0125] 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.

[0126] 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 via the optical transmission path L. Therefore, the receiving port of the communication device 30 is connected to the port 11-2 registered as a pair with the port 11-1. Therefore, the control unit 20 causes the transmitter 137 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, including information necessary for authentication, registration, and optical path opening.

[0127] Next, suppose that a user connects to the optical node device 10a by connecting one optical transmission line L to the communication device 40-1. As a result, suppose that the wavelength multiplexing / demultiplexing unit 45-1 of the communication device 40-1 is connected to the port 11-4 of the optical node device 10a via the optical transmission line L, as shown in FIG.

[0128] However, the control unit 20 cannot determine which of the multiple ports 11 of the optical node device 10a the communication device 40-1 is connected to. After connecting to the optical node device 10a, the communication device 40-1 generates an upstream control signal including type information. The control signal transmitter 41-1 of the communication device 40-1 converts the generated upstream control signal into an optical signal and sends it out as upstream control signal light.

[0129] The upstream control signal light sent from the control signal transmitter 41-1 of the communication device 40-1 is input to the port 11-4 of the optical node device 10a. The upstream control signal light input to the port 11-4 is output by the wavelength multiplexing / demultiplexing unit 12-4 toward the control transceiver 13a-2. The wavelength multiplexing / demultiplexing unit 135 of the control transceiver 13a-2 outputs the upstream control signal light output from the wavelength multiplexing / demultiplexing unit 12-4 to the receiver 136. The receiver 136 detects and demodulates the upstream control signal light. The receiver 136 outputs the demodulated upstream control signal to the control unit 20 via a control line (not shown).

[0130] In response to receiving the upstream control signal, the control unit 20 recognizes that a new connecting device has been connected to the optical node device 10a. Furthermore, the control unit 20 recognizes that the communication device 40-1 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 connecting device has been connected to the port 11-4 associated with the control transceiver 13a-2 that includes the receiver 136 that output the upstream control signal.

[0131] 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.

[0132] When the communication device 40-1 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 13a-2, which is connected to the identified port 11-4 via the wavelength multiplexing / demultiplexing unit 12-4, to transmit a downstream control signal. The control unit 20 outputs the downstream control signal, which includes type information, to the control transceiver 13a-2.

[0133] The timing control unit 138 of the control transceiver 13a-2 determines that the connected communication device is a communication device 40 that performs single-core bidirectional transmission, based on the type information included in the downstream control signal output from the control unit 20. The timing control unit 138 adjusts the transmission time (transmission timing) of the control signal with the communication device 40-1. The timing control unit 138 causes the transmitter 137 to transmit the downstream control signal output from the control unit 20 during the transmission time period determined by the adjustment. As a result, the control unit 20 exchanges control signal light, including information necessary for authentication, registration, and optical path opening, with the communication device 40-1 via the optical node device 10a, by time division multiplexing. Note that control signals other than information necessary for optical path opening are also exchanged between the optical node device 10a and the communication device 40-1 by time division multiplexing.

[0134] According to the optical communication system 100a configured as above, it is possible to obtain the same effects as those of the first embodiment.

[0135] 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.

[0136] 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.

[0137] 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).

[0138] Although an embodiment of the present invention has been described in detail above with reference to the drawings, the specific configuration is not limited to this embodiment, and includes designs within the scope of the gist of the present invention.

[0139] The present invention can be applied to a technique for opening an optical path.

[0140] 10, 10a... Optical node device, 11, 11-1 to 11-6... Port, 12, 12-1 to 12-6, 35, 36, 45-1 to 45-2, 131... Wavelength multiplexing / demultiplexing unit, 13, 13-1 to 13-6, 13a... Control transceiver, 20... Control unit, 30, 40, 40-1 to 40-2... Communication device, 31, 41-1 to 41-2... Control signal transmitter, 32, 42-1 to 42-2... Control signal receiver, 33, 43-1 to 43-2... Main signal transmitter, 34, 44-1 to 44-2... Main signal receiver, 46-1 to 46-2, 134... Timing control unit, 100, 100a... Optical communication system, 132... Receiver, 133... Transmitter

Claims

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, a plurality of ports to which the one or more communication devices are connected; one or more transceivers 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; Equipped with The one or more transceivers: When the one or more communication devices are communication devices that perform single-core bidirectional transmission, one or more timing control units that adjust transmission timings of control signals between the one or more communication devices; one or more transmitters that transmit downstream control signal light addressed to the one or more communication devices at the transmission timing adjusted by the one or more timing control units, when the one or more communication devices are communication devices that perform single-core bidirectional transmission; one or more second wavelength multiplexing / demultiplexing units that output the downstream control signal light transmitted from the one or more transmitters to at least one of the first wavelength multiplexing / demultiplexing units connected thereto; An optical node device comprising: 　 The one or more timing control units adjusting the transmission timing of the control signal so that the transmission timing of the upstream control signal light transmitted by the one or more communication devices differs from the transmission timing of the downstream control signal light transmitted by the one or more transmitters; The optical node device according to claim 1 . 　 When the one or more communication devices are communication devices that perform two-core transmission, the one or more transmitters transmit downstream control signal light addressed to the one or more communication devices as continuous light.

3. The optical node device according to claim 1. 　 The one or more transceivers: When the one or more newly connected communication devices are communication devices that perform two-core transmission, the downstream control signal light is sent from 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, toward the one or more newly connected communication devices.

3. The optical node device according to claim 1. 　 The one or more transceivers: When the one or more newly connected communication devices are communication devices that perform single-core bidirectional transmission, the downstream control signal light is sent 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.

3. The optical node device according to claim 1. 　 The one or more transceivers: a plurality of the one or more receivers, the one or more transmitters, the one or more second wavelength multiplexing / demultiplexing units, and the one or more timing control units; When the one or more newly connected communication devices are communication devices that perform two-core transmission, a downstream control signal light is sent 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, toward the one or more newly connected communication devices; When the one or more newly connected communication devices are communication devices that perform single-core bidirectional transmission, the downstream control signal light is sent from a transmitter corresponding to a port to which the upstream control signal light transmitted from the one or more newly connected communication devices is input, to the one or more newly connected communication devices.

3. The optical node device according to claim 1. 　 one or more timing control units that adjust the transmission timing of control signals between the one or more connected communication devices when the one or more connected communication devices are communication devices that perform single-core bidirectional transmission; one or more transmitters that transmit downstream control signal light addressed to the one or more communication devices at the transmission timing adjusted by the one or more timing control units, when the one or more communication devices are communication devices that perform single-core bidirectional transmission; one or more second wavelength multiplexers / demultiplexers that output the downstream control signal light transmitted from the one or more transmitters to a first wavelength multiplexer / demultiplexer connected to the one or more communication devices; A transceiver comprising: A connection method performed by an optical node device provided between one or more communication devices that perform single-core bidirectional transmission or two-core transmission and a control device that controls the one or more communication devices, comprising: One or more transceivers are connected to at least one port among the 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 transmit and receive control signal light to and from the one or more communication devices, When the one or more communication devices are communication devices that perform single-core bidirectional transmission, adjusting transmission timing of a control signal between the one or more communication devices; When the one or more communication devices are communication devices that perform single-core bidirectional transmission, transmitting downstream control signal light addressed to the one or more communication devices at the adjusted transmission timing; outputting the downstream control signal light transmitted from the one or more transmitters to at least one of the first wavelength multiplexing / demultiplexing units connected thereto; How to connect.

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