Optical node device, optical communication system, and wavelength confirmation method

Abstract

An optical node device according to the present invention comprises an optical transfer unit that transfers an optical signal transmitted from at least one newly connected new subscriber device to a specific port and a wavelength confirmation unit that is connected to the specific port and determines whether the wavelength of the optical signal transmitted from the at least one new subscriber device is appropriate on the basis of the optical signal transferred from the optical transfer unit.　

Description

Optical node device, optical communication system, and wavelength confirmation method

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

[0002] Conventionally, an optical communication system has been proposed that can connect subscriber devices located at arbitrary points end-to-end on a wavelength-by-wavelength basis (see, for example, Patent Document 1). In the optical communication system, an optical path must be opened between the subscriber devices that communicate. Here, a method for opening an optical path for a subscriber device to connect to a subscriber device with which it is to communicate via an optical transmission line and one or more optical node devices will be described with reference to FIG. 9 .

[0003] FIG. 9 is a diagram for explaining an optical path opening method in an optical communication system. As shown in FIG. 9, the optical communication system S includes multiple optical node devices 1-1 to 1-3 and multiple control units 2-1 to 2-2. A subscriber device 3 is connected to the optical node device 1-1 via an optical transmission path L. A subscriber device 4 is connected to the optical node device 1-2 via an optical transmission path L. A subscriber device 5 is connected to the optical node device 1-3 via an optical transmission path L. The optical node devices 1-1 and 1-3, and the optical node devices 1-1 and 1-2 are connected via multiple optical transmission paths L. Hereinafter, when there is no need to distinguish between the subscriber devices 3, 4, and 5, they will simply be referred to as subscriber devices.

[0004] The control unit 2-1 controls the optical node device 1-1 and the subscriber device 3 connected to the optical node device 1-1. The control unit 2-2 controls the optical node device 1-2 and the subscriber device 4 connected to the optical node device 1-2. The control unit 2-3 (not shown) controls the optical node device 1-3 and the subscriber device 5 connected to the optical node device 1-3. The control unit 2-1 includes a subscriber device management control unit 6-1 and a node control unit 7-1. The control unit 2-2 includes a subscriber device management control unit 6-2 and a node control unit 7-2. Here, the operations performed by the control units 2-1 and 2-2 are the same, so they will not be distinguished (no branch numbers will be added to the reference numerals). The subscriber device management control unit 6 controls the subscriber devices connected to the optical node device 1 (for example, wavelength allocation, etc.). The node control unit 7 controls routes in the optical node device 1 so that the subscriber devices can communicate with other subscriber devices.

[0005] The optical node device 1 is a node device that constitutes a wavelength network, and accommodates one or more subscriber devices 3, 4, and 5. The optical node device 1 includes multiple wavelength distribution units 8 and a WXC unit 9. The wavelength distribution unit 8 distributes one or more input optical signals. Specifically, the wavelength distribution unit 8 performs an add operation and a drop operation. The add operation is an operation of multiplexing optical signals having the same output route from optical signals transmitted from multiple subscriber devices, and outputting the multiple multiplexed optical signals to the WXC unit 9 for each route. The drop operation is an operation of outputting optical signals input from multiple routes and addressed to each subscriber device so that they reach the subscriber device.

[0006] The WXC unit 9 wavelength-multiplexes or wavelength-demultiplexes optical signals for each path. The WXC unit 9 includes a plurality of wavelength multiplexing units 91 and a plurality of wavelength demultiplexing units 92. The WXC unit 9 includes a combination of one wavelength multiplexing unit 91 and one wavelength demultiplexing unit 92 for at least each path. Since FIG. 9 shows an example in which there are two paths, the WXC unit 9 includes at least two wavelength multiplexing units 91 and two wavelength demultiplexing units 92. Here, the combination of one wavelength multiplexing unit 91 and one wavelength demultiplexing unit 92 will be described as a wavelength multiplexing / demultiplexing unit.

[0007] The wavelength multiplexing / demultiplexing unit multiplexes the optical signals input from each wavelength distribution unit 8 and outputs the multiplexed optical signals to the optical transmission line L side, demultiplexes the wavelength-multiplexed optical signals from the optical transmission line L side according to wavelength, and demultiplexes and outputs the demultiplexed optical signals of each wavelength according to wavelength to the wavelength distribution unit 8 that accommodates the subscriber device that is the destination of each optical signal. Note that the wavelength multiplexing / demultiplexing unit outputs, among the wavelength-multiplexed optical signals input from the optical transmission line L side, optical signals addressed to subscriber devices accommodated in optical node devices at other bases to the wavelength multiplexing / demultiplexing unit of the path to that base.

[0008] When a subscriber device is newly connected to an optical node device via an optical transmission path L, information necessary for authentication and registration of the new subscriber device is exchanged between the newly connected subscriber device (hereinafter referred to as "new subscriber device") and the subscriber device management and control unit 6. The new subscriber devices are assumed to be subscriber devices 3-1 and 3-2. The subscriber device management and control unit 6 also instructs the new subscriber devices to allocate and set an emission wavelength so that the wavelength does not overlap with that of other optical paths along the transmission route. This allows the new subscriber device to set the wavelength to be used for communication. The new subscriber device then transmits an optical signal at the wavelength instructed by the subscriber device management and control unit 6.

[0009] Upon completion of the authentication and registration of the new subscriber device and the wavelength setting, the node control unit 7 performs internal forwarding settings in the wavelength distribution unit 8 and WXC unit 9 constituting the optical node device 1 so that the optical signal transmitted from the new subscriber device is forwarded to the subscriber device with which it will communicate. As a result, it is possible to open an optical path that directly connects subscriber device 3-1 to subscriber device 4-1 with which it will communicate, and an optical path that directly connects subscriber device 3-2 to subscriber device 4-2 with which it will communicate.

[0010] International Publication No. 2023 / 135737

[0011] H. Nishizawa et al., “Dynamic optical path provisioning for alien access links: Architecture, demonstration, and challenges,” IEEE Commun. Mag., vol. 61, no. 4, pp. 136-142, Apr. 2023, doi: https: / / doi.org / 10.1109 / MCOM.006.2200567.

[0012] When a new optical path is opened in the conventional optical communication system S, it is possible that the new subscriber device will transmit an optical signal (hereinafter referred to as an "illegal optical signal") having a wavelength different from the emission wavelength instructed by the subscriber device management control unit 6. For example, if a subscriber device fails or malfunctions, or if a subscriber intentionally sets an illegal wavelength, it is conceivable that the new subscriber device will transmit an illegal optical signal.

[0013] In this case, if the wavelength of an already opened optical path that is assigned the same route as the optical path to be newly opened overlaps with the wavelength of the unauthorized optical signal, a communication interruption may occur even in the already opened optical path. Figure 10 is a diagram for explaining the conventional problem. Here, an example will be described in which the wavelength distribution unit 8 has a multicast switch type configuration that includes multiple optical switches 81 and multiple optical couplers 82 and multiplexes optical signals using the optical couplers, but the wavelength distribution unit 8 is not limited to this configuration.

[0014] As shown in FIG. 10, the subscriber device management control unit 6 assigns a wavelength λ 1 to the subscriber device 3-1. １ and assigns a wavelength λ ２ The subscriber device 3-1 is assigned the wavelength λ １ The subscriber device 3-2 transmits an optical signal of the assigned wavelength λ ２ Instead, wavelength λ １ When optical signals of the same wavelength are transmitted, the optical coupler 82 multiplexes the optical signals of the same wavelength, causing a collision of the optical signals and resulting in a communication interruption in the opened optical path.

[0015] In view of the above circumstances, an object of the present invention is to provide a technology that can suppress communication interruptions to optical paths that have already been opened.

[0016] One aspect of the present invention is an optical node device comprising an optical forwarding unit that forwards optical signals transmitted from at least one or more newly connected new subscriber devices to a specific port, and a wavelength confirmation unit that is connected to the specific port and determines whether the wavelengths of the optical signals transmitted from the one or more new subscriber devices are appropriate based on the optical signals forwarded from the optical forwarding unit.

[0017] One aspect of the present invention is an optical communication system comprising: a subscriber device management control unit that assigns wavelengths to be used for communication to at least one or more newly connected new subscriber devices; a node control unit that controls at least the connection of ports to which the new subscriber devices are connected; an optical forwarding unit that forwards optical signals transmitted from the new subscriber devices to specific ports in accordance with the control of the node control unit; and a wavelength confirmation unit that is connected to the specific port and that determines whether the wavelengths of the optical signals transmitted from the one or more new subscriber devices are appropriate based on the optical signals forwarded from the optical forwarding unit.

[0018] One aspect of the present invention is a wavelength confirmation method that transfers optical signals transmitted from at least one or more newly connected new subscriber devices to a specific port, and determines whether the wavelengths of the optical signals transmitted from the one or more new subscriber devices are appropriate based on the optical signals transferred via the specific port.

[0019] According to the present invention, it is possible to prevent communication interruptions to optical paths that have already been opened.

[0020] FIG. 1 is a diagram illustrating an example of the configuration of an optical communication system in a first embodiment. FIG. 2 is a diagram illustrating an example of the configuration of a wavelength monitor unit in the first embodiment. FIG. 3 is a sequence diagram illustrating the flow of an optical path opening process in the optical communication system in the first embodiment. FIG. 4 is a diagram illustrating a state after an optical path is opened in the optical communication system in the first embodiment. FIG. 5 is a diagram illustrating an example of the configuration of an optical communication system in a modified example of the first embodiment. FIG. 6 is a diagram illustrating an example of the configuration of an optical communication system in a second embodiment. FIG. 7 is a sequence diagram illustrating the flow of an optical path opening process in the optical communication system in the second embodiment. FIG. 8 is a diagram illustrating a state after an optical path is opened in the optical communication system in the second embodiment. FIG. 9 is a diagram for explaining an optical path opening method in an optical communication system. FIG. 10 is a diagram for explaining problems of the related art.

[0021] Hereinafter, an embodiment of the present invention will be described with reference to the drawings.

[0022] 1 is a diagram showing an example of the configuration of an optical communication system 100 according to the first embodiment. The optical communication system 100 includes an optical node device 10 and a control unit 20. One or more subscriber devices 30 are connected to the optical node device 10 via an optical transmission path L. The optical transmission path L is, for example, an optical fiber.

[0023] Although not shown in FIG. 1 for simplicity, the optical communication system 100 includes a plurality of optical node devices and a control unit as shown in FIG. 9. The optical communication system 100 may include a control unit for each optical node device, or may include one control unit for a plurality of optical node devices. The optical node device 10 is connected to another optical node device or one subscriber device via an optical transmission path L at a port different from the port to which one subscriber device 30 is connected. The same applies to the following embodiments. In the first embodiment, an example will be described in which a subscriber device 30 transmits an optical signal, and a subscriber device (not shown) receives the optical signal transmitted from the subscriber device 30.

[0024] In the following description, the direction from the subscriber device 30 toward the control unit 20 is referred to as the upstream direction, and the direction from the control unit 20 toward the subscriber device 30 is referred to as the downstream direction. The number of optical node devices 10 and subscriber devices 30 is not particularly limited.

[0025] The optical node device 10 is a node device that constitutes a wavelength network, and accommodates one or more subscriber devices 30. The optical node device 10 includes an optical transfer unit 11, a plurality of wavelength distribution units 12, a WXC unit 13, and a wavelength monitor unit 14.

[0026] The optical transfer unit 11 has a plurality of first ports and a plurality of second ports. The optical transfer unit 11 sets connections between the ports in response to instructions from the control unit 20, thereby outputting an input optical signal from another port regardless of wavelength. The optical transfer unit 11 is, for example, an optical switch based on a piezoelectric actuator or a MEMS (Micro Electro Mechanical Systems). One or more subscriber devices 30 are connected to the plurality of first ports via optical transmission paths L. The wavelength distribution unit 12 or wavelength monitor unit 14 is connected to the plurality of second ports.

[0027] In response to an instruction from the control unit 20, the optical forwarding unit 11 connects the port to which the new subscriber device is connected to the port to which the wavelength monitor unit 14 is connected. Here, the port to which the wavelength monitor unit 14 is connected is a specific port among a plurality of second ports provided in the optical forwarding unit 11 that is used to determine the wavelength of the optical signal transmitted by the new subscriber device. Here, determining the wavelength of the optical signal transmitted by the new subscriber device means confirming whether the optical signal transmitted by the new subscriber device is set correctly. In this way, by connecting the port to which the new subscriber device is connected to the port to which the wavelength monitor unit 14 is connected, the optical signal transmitted from the new subscriber device can be forwarded to the wavelength monitor unit 14.

[0028] The wavelength distribution unit 12 distributes one or more input optical signals. Specifically, the wavelength distribution unit 12 performs an add operation and a drop operation.

[0029] The WXC unit 13 wavelength-multiplexes or wavelength-demultiplexes optical signals for each path. The WXC unit 13 includes a plurality of wavelength multiplexing units 131 and a plurality of wavelength demultiplexing units 132. The WXC unit 13 includes a combination of one wavelength multiplexing unit 131 and one wavelength demultiplexing unit 132 for at least each path. Since FIG. 1 shows an example in which there are two paths, the WXC unit 13 includes at least two wavelength multiplexing units 131-1 to 131-2 and two wavelength demultiplexing units 132-1 to 132-2. It is sufficient that the WXC unit 13 includes two or more combinations of wavelength multiplexing units 131 and wavelength demultiplexing units 132.

[0030] The wavelength multiplexing unit 131 multiplexes the optical signals input from each wavelength distribution unit 12 and outputs the multiplexed optical signals to the optical transmission line L. The wavelength demultiplexing unit 132 demultiplexes the wavelength-multiplexed optical signal input from the optical transmission line L according to wavelength, and outputs the demultiplexed optical signals of each wavelength to the wavelength distribution unit 12 accommodating the subscriber device that is the destination of each optical signal. Note that the wavelength demultiplexing unit 132 outputs, among the wavelength-multiplexed optical signals input from the optical transmission line L, an optical signal addressed to a subscriber device accommodated in an optical node device at another base, to the wavelength multiplexing / demultiplexing unit of the path to that base.

[0031] The wavelength monitor 14 determines whether the wavelength of the optical signal transferred from the optical transfer unit 11 matches the wavelength assigned to the new subscriber device notified by the node control unit 22 of the control unit 20. That is, the wavelength monitor 14 checks whether the wavelength of the optical signal transferred from the optical transfer unit 11 is an appropriate wavelength. The wavelength monitor 14 transmits a control signal indicating the determination result to the control unit 20. Here, the determination result by the wavelength monitor 14 includes information indicating whether the wavelength of the optical signal transferred from the optical transfer unit 11 matches the wavelength assigned to the new subscriber device.

[0032] If the wavelength of the optical signal transferred from the optical transfer unit 11 matches the wavelength assigned to the new subscriber device, the wavelength monitor unit 14 transmits a control signal to the control unit 20 indicating the determination result that the wavelength is appropriate. If the wavelength of the optical signal transferred from the optical transfer unit 11 does not match the wavelength assigned to the new subscriber device, the wavelength monitor unit 14 transmits a control signal to the control unit 20 indicating the determination result that the wavelength is incorrect. The specific configuration of the wavelength monitor unit 14 will be described later. The wavelength monitor unit 14 is one aspect of a wavelength confirmation unit.

[0033] The control unit 20 controls the optical node device 10 and the subscriber device 30. Here, the control of the optical node device 10 includes, for example, setting up connections between ports of the optical forwarding unit 11, wavelength distribution unit 12, and WXC unit 13 (for example, setting up a transfer path), and notifying the wavelength monitor unit 14 of a wavelength assigned to a new subscriber device. The control of the subscriber device 30 includes, for example, processing such as authentication and registration with the new subscriber device, assigning an emission wavelength to the subscriber device 30, issuing an optical stop command, issuing an instruction to change the wavelength, and the like.

[0034] The control unit 20 includes a subscriber device management control unit 21 and a node control unit 22. The subscriber device management control unit 21 performs the above-mentioned control on the subscriber devices 30 (including, for example, subscriber devices 30 already connected to the optical node device 10 and new subscriber devices) connected to the optical node device 10. Furthermore, the subscriber device management control unit 21 may issue a warning to the new subscriber device when the determination result output from the wavelength monitor unit 14 indicates an invalidity.

[0035] The node control unit 22 controls the path in the optical node device 10 and notifies the new subscriber device of the wavelength assigned by the subscriber device management control unit 21 so that the subscriber device 30 can communicate with the subscriber device that is the communication partner. For the new subscriber device, the node control unit 22 sets up a connection between ports inside the optical forwarding unit 11 so that the optical signal output from the new subscriber device is forwarded to the wavelength monitoring unit 14.

[0036] If the determination result output from the wavelength monitor unit 14 indicates that the optical path is correct, the node control unit 22 sets the internal port connections of the optical forwarding unit 11 so that the optical signal transmitted from the new subscriber device is output to the wavelength distribution unit 12 that outputs the optical signal to the route assigned to the newly opened optical path. Furthermore, the node control unit 22 performs internal forwarding settings of the wavelength distribution unit 12 and the WXC unit 13. For example, the node control unit 22 performs route control in the optical node device 10 so that the new subscriber device can communicate with a subscriber device with which it will communicate. This makes it possible to open an optical path so that the optical signal transmitted from the new subscriber device is forwarded to the subscriber device with which it will communicate.

[0037] On the other hand, if the determination result output from the wavelength monitor 14 indicates an invalidity, the node control unit 22 sets the inter-port connection of the optical forwarding unit 11 so that the optical signal transmitted from the new subscriber device is not output to any wavelength distribution unit 12. For example, the node control unit 22 maintains the inter-port connection of the optical forwarding unit 11 so that the optical signal transmitted from the new subscriber device is continuously forwarded to the wavelength monitor 14, or sets the port to which the new subscriber device is connected not to be internally connected to any other port. In this way, the node control unit 22b controls so that the optical signal transmitted from the new subscriber device does not affect the communications of other subscriber devices to which optical paths have already been opened until the set wavelength of the new subscriber device is set to the correct wavelength. This makes it possible to prevent an optical signal with a wavelength different from the originally assigned wavelength from being forwarded to the wavelength distribution unit 12.

[0038] The subscriber device 30 includes an optical transceiver. The optical transceiver is, for example, a coherent transceiver. The subscriber device 30 transmits and receives optical signals such as main signals and control signals using the optical transceiver. When a subscriber device 30 is newly connected to the optical communication system 100 before an optical path is opened, the subscriber device 30 exchanges information necessary for registration, authentication, and optical path opening with the control unit 20. The information necessary for optical path opening includes, for example, information on the wavelengths used for transmission and reception, and information on the subscriber device with which communication is to be performed.

[0039] The subscriber device 30 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 subscriber device 30 is, for example, an ONU (Optical Network Unit) installed in a subscriber's home.

[0040] Next, the configuration of the wavelength monitor 14 will be described with reference to FIG. 2. FIG. 2 is a diagram showing an example of the configuration of the wavelength monitor 14 in the first embodiment. FIG. 2 shows three configuration examples of the wavelength monitor 14. The wavelength monitor 14 shown in FIG. 2A is composed of a wavelength-tunable filter 141, a photoreceiver 142, a light intensity measurement unit 143, and a control unit 144. The wavelength-tunable filter 141 is a filter that has the function of transmitting an optical signal of a specific wavelength. The transmission wavelength of the wavelength-tunable filter 141 is set by the control unit 144. For example, the transmission wavelength of the wavelength-tunable filter 141 is the wavelength assigned to the new subscriber device, which is notified by the control unit 20. This allows the wavelength-tunable filter 141 to transmit an optical signal of the wavelength assigned to the new subscriber device to the photoreceiver 142, and to block optical signals of other wavelengths.

[0041] The photoreceiver 142 receives the optical signal that has passed through the wavelength-tunable filter 141. The light intensity measurement unit 143 measures the intensity of the light received by the photoreceiver 142. The control unit 144 controls the function of the wavelength monitor unit 14. The control unit 144 sets the wavelength notified by, for example, the control unit 20 to the wavelength-tunable filter 141. The control unit 144 determines whether the wavelength of the optical signal input to the wavelength monitor unit 14 is appropriate based on the light intensity measured by the light intensity measurement unit 143. If the wavelength of the optical signal input to the wavelength monitor unit 14 is appropriate, the control unit 144 transmits a control signal to the control unit 20 indicating the determination result that the wavelength is appropriate. If the wavelength of the optical signal input to the wavelength monitor unit 14 is inappropriate, the control unit 144 transmits a control signal to the control unit 20 indicating the determination result that the wavelength is incorrect.

[0042] One method for determining whether the wavelength of the optical signal input to the wavelength monitor unit 14 is appropriate is, for example, to compare a predetermined threshold value with the intensity of light measured by the optical intensity measurement unit 143. The predetermined threshold value is a minimum optical intensity that is specified to be input to the photodetector 142 when the wavelength of the optical signal input to the wavelength monitor unit 14 matches the transmission wavelength of the tunable filter 141. If the intensity of light measured by the optical intensity measurement unit 143 is equal to or greater than the threshold value, the control unit 144 determines that the optical signal is appropriate (i.e., the wavelength of the optical signal input to the wavelength monitor unit 14 matches the transmission wavelength of the tunable filter 141). On the other hand, if the intensity of light measured by the optical intensity measurement unit 143 is less than the threshold value, the control unit 144 determines that the optical signal is incorrect (i.e., the wavelength of the optical signal input to the wavelength monitor unit 14 does not match the transmission wavelength of the tunable filter 141).

[0043] Another example of a method for determining whether the wavelength of the optical signal input to the wavelength monitor unit 14 is appropriate is to measure the optical intensity upstream of the wavelength-tunable filter 141 and use the transmission loss value of the wavelength-tunable filter 141, which can be calculated based on the difference between the optical intensity measured by the optical intensity measurement unit 143 and the measured optical intensity. The control unit 144 determines that the transmission loss value is appropriate (the wavelength of the optical signal input to the wavelength monitor unit 14 matches the transmission wavelength of the wavelength-tunable filter 141) when the transmission loss value is equal to or less than the maximum allowable transmission loss value of the wavelength-tunable filter 141. On the other hand, the control unit 144 determines that the wavelength of the optical signal input to the wavelength monitor unit 14 is incorrect (the wavelength of the optical signal input to the wavelength monitor unit 14 does not match the transmission wavelength of the wavelength-tunable filter 141) when the transmission loss value is greater than the maximum allowable transmission loss value of the wavelength-tunable filter 141.

[0044] The device placed in the preceding stage of the photodetector 142 may be any device that has the function of selectively transmitting wavelengths, and a wavelength selective switch (WSS) as shown in Fig. 2B or an arrayed waveguide grating (AWG) as shown in Fig. 2C may be used instead of the wavelength tunable filter 141. In the configurations shown in Fig. 2B or 2C, the wavelength tunable filter 141 in the above determination method may be replaced with a wavelength selective switch or an arrayed waveguide grating.

[0045] The wavelength monitor 14 shown in FIG. 2B is composed of a photoreceiver 142, an optical intensity measurement unit 143, a control unit 144, and a WSS 145. The wavelength monitor 14 shown in FIG. 2B is provided with the WSS 145 upstream of the photoreceiver 142. The WSS 145 has the function of selectively transmitting wavelengths. The WSS 145 transmits optical signals of specific wavelengths. The wavelengths transmitted by the WSS 145 are set by the control unit 144. For example, the wavelengths transmitted by the WSS 145 are wavelengths assigned to the new subscriber device, as notified by the control unit 20. This allows the WSS 145 to transmit optical signals of the wavelengths assigned to the new subscriber device to the photoreceiver 142.

[0046] The wavelength monitor 14 shown in Fig. 2C is composed of a plurality of photodetectors 142, a light intensity measuring unit 143, a control unit 144, and an AWG 146. The number of photodetectors 142 is equal to the number of output ports of the AWG 146. The wavelength monitor 14 shown in Fig. 2C is provided with the AWG 146 in front of the plurality of photodetectors 142. The AWG 146 outputs the input optical signal from an output port corresponding to the wavelength.

[0047] (Flow of optical path opening process in optical communication system 100) Figure 3 is a sequence diagram showing the flow of optical path opening process in the optical communication system 100 in the first embodiment. Note that in Figure 3, the explanation will be given assuming that the new subscriber device is subscriber device 30-2. Also, in the explanation of Figure 3, the configuration of the wavelength monitor unit 14 will be explained using the configuration shown in Figure 2(A) as an example.

[0048] Assume that a user connects subscriber device 30-2 to the optical node device 10 via the optical transmission path L. As a result, subscriber device 30-2 is connected to the optical node device 10 via the optical transmission path L (step S101). Subscriber device 30-2 generates an upstream control signal including instructions requesting authentication, registration, etc. Subscriber device 30-2 converts the generated upstream control signal into an optical signal and transmits it as upstream control signal light. The upstream control signal light may be output from subscriber device 30-2 to the same optical transmission path as the signal light transmitted from subscriber device 30-2 to its communication partner subscriber device, or may be output to a different optical transmission path. The upstream control signal light transmitted from subscriber device 30-2 is forwarded to the control unit 20 by the optical node device 10. When connecting a new subscriber device, an existing method may be used to forward the optical signal transmitted from the new subscriber device to the control unit 20.

[0049] The subscriber device management control unit 21 of the control unit 20 exchanges control signal light with the subscriber device 30-2, including information necessary for authentication, registration, and optical path opening (step S102). As a result, the subscriber device management control unit 21 recognizes the new subscriber device, and instructs the subscriber device 30-2, which is the recognized new subscriber device, to allocate and set an emission wavelength so that the wavelength does not overlap with other optical paths on the transmission route. Here, the wavelength λ １ , λ ３ , λ ４ is already assigned to another subscriber unit. Therefore, the subscriber unit management control unit 21 assigns the wavelength λ 1 to the subscriber unit 30-2. ２ In this example, the subscriber unit 30-2 is assigned a wavelength λ ２ However, other wavelengths may be used as long as they do not overlap with other optical paths along the transmission route. The subscriber device management control unit 21 transmits an optical signal including an emission wavelength allocation and setting instruction to the subscriber device 30-2 via the optical node device 10.

[0050] The subscriber device management and control unit 21 notifies the node control unit 22 of information indicating the wavelength assigned to the subscriber device 30-2. Upon receiving the notification from the subscriber device management and control unit 21, the node control unit 22 sets up a port connection within the optical forwarding unit 11 so that the optical signal output from the subscriber device 30-2 is forwarded to the wavelength monitor unit 14 (step S103). Specifically, the node control unit 22 generates a switching instruction to connect the port of the optical forwarding unit 11 to which the subscriber device 30-2 is connected and the port to which the wavelength monitor unit 14 is connected, and generates a control signal including the generated switching instruction and information indicating the wavelength notified by the subscriber device management and control unit 21. The node control unit 22 transmits the generated control signal to the optical node device 10 via a control line (not shown) (step S104). Note that the node control unit 22 may transmit the switching instruction and the information indicating the wavelength at different times.

[0051] The optical node device 10 receives the control signal transmitted from the control unit 20. The optical node device 10 outputs a switching instruction included in the received control signal to the optical transfer unit 11, and outputs information indicating the wavelength to the wavelength monitor unit 14. In response to the switching instruction, the optical transfer unit 11 switches the connection between the ports so that the port to which the subscriber device 30-2 is connected and the port to which the wavelength monitor unit 14 is connected are connected (step S105). In response to the information indicating the wavelength, the control unit 144 of the wavelength monitor unit 14 sets the wavelength to be transmitted by the wavelength tunable filter 141 to the wavelength λ ２ Set to.

[0052] The subscriber device 30-2 receives the optical signal including the emission wavelength allocation and setting instruction transmitted from the control unit 20. The subscriber device 30-2 receives the wavelength λ 1 specified by the emission wavelength allocation included in the received optical signal. ２ The subscriber unit 30-2 sets the set wavelength λ ２ If there is no failure or malfunction in the subscriber unit 30-2, or if the subscriber has intentionally set an incorrect wavelength, the set wavelength λ ２On the other hand, if the subscriber unit 30-2 has a failure or malfunction, or if a subscriber intentionally sets an incorrect wavelength, the set wavelength λ ２ (e.g., wavelength λ １ Optical signals such as (e.g., optical fiber) may be transmitted.

[0053] The optical signal transmitted from the subscriber device 30-2 is input to the optical transfer unit 11 via the optical transmission line L. The optical transfer unit 11 outputs the input optical signal from the port to which the wavelength monitor unit 14 is connected. As a result, the optical signal transmitted from the subscriber device 30-2 is transferred to the wavelength monitor unit 14 (step S107). The wavelength monitor unit 14 monitors the optical signal transferred by the optical transfer unit 11 (step S108).

[0054] Specifically, the tunable filter 141 of the optical transfer unit 11 transmits the input optical signal if the wavelength of the input optical signal is a set transmission wavelength, and blocks the input optical signal if the wavelength is not the set transmission wavelength. The optical receiver 142 receives the optical signal that has passed through the tunable filter 141. The optical intensity measurement unit 143 measures the intensity of the optical signal received by the optical receiver 142. The optical intensity measurement unit 143 outputs the measurement result to the control unit 144. The control unit 144 determines whether the wavelength of the optical signal input to the wavelength monitor unit 14 is appropriate based on the above-mentioned determination method.

[0055] The control unit 144 generates a control signal including a determination result that the wavelength of the optical signal input to the wavelength monitor unit 14 is appropriate if the wavelength of the optical signal input to the wavelength monitor unit 14 is appropriate, and generates a control signal including a determination result that the wavelength of the optical signal input to the wavelength monitor unit 14 is incorrect if the wavelength of the optical signal input to the wavelength monitor unit 14 is incorrect. The control unit 144 transmits the generated control signal to the control unit 20 via a control line (not shown) (step S109).

[0056] The node control unit 22 of the control unit 20 receives the control signal transmitted from the optical node device 10. The node control unit 22 performs control according to the determination result contained in the received control signal (step S110). Specifically, when the determination result contained in the control signal indicates that the determination result is correct, the node control unit 22 sets up the internal port connections of the optical forwarding unit 11 as shown in FIG. 4 so that the optical signal transmitted from the subscriber device 30-2 is output to the wavelength distribution unit 12 that outputs the optical signal to the route assigned to the newly opened optical path. Furthermore, the node control unit 22 performs internal forwarding settings of the wavelength distribution unit 12 and the WXC unit 13. As a result, as shown in FIG. 4, the optical path can be opened so that the optical signal transmitted from the subscriber device 30-2 is forwarded to the subscriber device with which it is communicating.

[0057] On the other hand, if the determination result included in the control signal indicates an invalidity, the node control unit 22 sets the inter-port connection of the optical forwarding unit 11 so that the optical signal output from the subscriber device 30-2 is not output to any of the wavelength distribution units 12. For example, the node control unit 22 maintains the inter-port connection so that the optical signal output from the subscriber device 30-2 is continuously forwarded to the wavelength monitoring unit 14, or performs control such as not internally connecting the port to which the subscriber device 30-2 is connected to any other port.

[0058] The optical communication system 100 configured as described above includes an optical transfer unit 11 that transfers an optical signal transmitted from a new subscriber device to a port assigned for determination, and a wavelength monitor unit 14 that determines whether the wavelength of the optical signal transmitted from the new subscriber device is appropriate based on the optical signal transferred from the optical transfer unit 11.

[0059] As a result, when an optical path is opened, it is possible to confirm whether a new subscriber device has set the wavelength and is transmitting an optical signal as instructed by the subscriber device management control unit 21. Then, only after it is confirmed that the wavelength has been set appropriately, the optical path is multiplexed with optical signals from other subscriber devices that have already been opened, thereby preventing interference with communications of other subscriber devices regardless of the configuration of the wavelength distribution unit 12. This makes it possible to prevent communication interruptions to optical paths that have already been opened.

[0060] When the wavelength monitor unit 14 monitors the optical intensity to determine whether the wavelength of the input light is appropriate, it is possible to check the input optical intensity of the optical signal transmitted by the new subscriber device to the optical node device 10. If the input optical intensity is equal to or greater than a specified value, the node control unit 22 sets the inter-port connection of the optical forwarding unit 11 so that the optical signal output from the new subscriber device is not output to any of the wavelength distribution units 12, thereby preventing damage to the wavelength distribution units 12 and WXC units 13 that constitute the optical node device due to excessive optical intensity input. In addition, it is possible to prevent degradation of the transmission characteristics of other optical signals due to crosstalk with other optical signals when excessive optical intensity is input.

[0061] (Modification) The optical communication system 100 shown in FIG. 1 may be modified as shown in FIG. 5. FIG. 5 is a diagram showing an example of the configuration of an optical communication system 100a in a modification of the first embodiment. The optical communication system 100a includes an optical node device 10a and a control unit 20. One or more subscriber devices 30 are connected to the optical node device 10a via an optical transmission path L. The optical communication system 100a differs in configuration from the optical communication system 100 in that it includes an optical node device 10a instead of the optical node device 10. Other configurations of the optical communication system 100a are similar to those of the optical communication system 100. The following description will focus on the differences from the optical communication system 100.

[0062] The optical node device 10a is a node device that constitutes a wavelength network and accommodates one or more subscriber devices 30. The optical node device 10a includes an optical forwarding unit 11, a WXC unit 13, a wavelength monitor unit 14, and multiple wavelength multiplexing / demultiplexing units 15. As shown in FIG. 5, the optical node device 10a includes multiple wavelength multiplexing / demultiplexing units 15 instead of multiple wavelength distribution units 12. Each wavelength multiplexing / demultiplexing unit 15 is connected to a different wavelength multiplexing unit 131 or wavelength demultiplexing unit 132. For example, each wavelength multiplexing / demultiplexing unit 15 used for upstream communication is connected to a different wavelength multiplexing unit 131-1, 131-2, and each wavelength multiplexing / demultiplexing unit 15 used for downstream communication is connected to a different wavelength demultiplexing unit 132-1, 132-2.

[0063] The wavelength multiplexing / demultiplexing unit 15 used for upstream communication multiplexes one or more optical signals transferred from the optical transfer unit 11 and outputs the multiplexed signal to the connected wavelength multiplexing unit 131. The wavelength multiplexing / demultiplexing unit 15 used for downstream communication demultiplexes an optical signal (e.g., a multiplexed signal) output from the WXC unit 13 and outputs the demultiplexed signal to the optical transfer unit 11.

[0064] By combining the optical transfer unit 11 and the wavelength multiplexing / demultiplexing unit 15, it is possible to realize the adding / dropping of optical signals. In the adding operation, the optical transfer unit 11 transfers the optical signal transmitted from the subscriber device 30 to a port of the wavelength multiplexing / demultiplexing unit 15 according to the wavelength, and then the wavelength multiplexing / demultiplexing unit 15 wavelength-multiplexes the optical signal to be output to the same path. In the dropping operation, the wavelength multiplexing / demultiplexing unit 15 demultiplexes the wavelength-multiplexed optical signal output from the WXC unit 13 according to wavelength, and the optical transfer unit 11 transfers the optical signal to a port on the subscriber device side according to the destination.

[0065] Even in such a configuration, when an optical path is opened, the node control unit 22 sets the inter-port connection within the optical transfer unit 11 so that the optical signal output from the new subscriber device is transferred to the wavelength monitor unit 14. When it is confirmed in the optical transfer unit 11 that the wavelength of the new subscriber device is properly set, the node control unit 22 sets the inter-port connection within the optical transfer unit 11 so that the optical signal output from the new subscriber device is output to the wavelength multiplexing / demultiplexing unit 15 that outputs the optical signal to the route assigned to the newly opened optical path.

[0066] Second Embodiment In the second embodiment, a configuration will be described in which the state of an optical transmission line connecting a subscriber device and an optical node device is estimated, and unauthorized signals are detected and blocked based on the estimated state of the optical transmission line.

[0067] FIG. 6 is a diagram showing an example configuration of an optical communication system 100b in the second embodiment. The optical communication system 100b includes an optical node device 10b and a control unit 20b. One or more subscriber devices 30 are connected to the optical node device 10b via an optical transmission path L. The optical communication system 100b differs in configuration from the optical communication system 100 in that the optical node device 10b and control unit 20b are included instead of the optical node device 10 and control unit 20. The other configuration of the optical communication system 100b is similar to that of the optical communication system 100. The following description will focus on the differences from the optical communication system 100. The second embodiment will be described taking as an example a case where a subscriber device 30 transmits an optical signal, and a subscriber device (not shown) receives the optical signal transmitted from the subscriber device 30.

[0068] The optical node device 10b is a node device that constitutes a wavelength network and accommodates one or more subscriber devices 30. The optical node device 10b includes an optical forwarding unit 11, multiple wavelength distribution units 12, a WXC unit 13, and a transmission path state estimation unit 16b. As shown in Fig. 6, the optical node device 10b includes the transmission path state estimation unit 16b instead of the wavelength monitoring unit 14.

[0069] The transmission path status estimator 16b estimates the status of the optical transmission path L connecting the subscriber device 30 and the optical node device 10. When designing an optical path connecting multiple subscriber devices that communicate with each other, transmission parameters such as the bit rate, modulation format, and FEC (Forward Error Correction) type are determined using the end-to-end transmission path status as input parameters. Here, the status of the optical transmission path L connecting the subscriber device 30 and the optical node device 10 differs for each optical transmission path and is unknown. Therefore, in the configuration shown in FIG. 6, the optical node device 10b is provided with a transmission path status estimator 16b, and at the beginning of the optical path opening procedure, the status of the optical transmission path L connecting the new subscriber device and the optical node device 10b is estimated by transmitting and receiving optical signals between the new subscriber device and the transmission path status estimator 16b. Note that the method shown in Non-Patent Document 1 may be used as a method for estimating the status of the optical transmission path L.

[0070] The transmission path state estimator 16b further includes a local oscillator. The wavelength of the light output from the local oscillator included in the transmission path state estimator 16b is close to the wavelength assigned to the new subscriber device. Therefore, the transmission path state estimator 16b controls the local oscillator so that it outputs light with a wavelength close to the wavelength assigned to the new subscriber device, as notified by the control unit 20b. The transmission path state estimator 16b multiplexes and detects the local oscillator, which has a wavelength close to the wavelength of the optical signal transmitted from the new subscriber device, with the optical signal transmitted from the new subscriber device. At this time, if the wavelength difference (optical frequency difference) between the optical signal transmitted from the new subscriber device and the local oscillator is outside the electrical band of the optical receiver performing the detection, the beat component between the optical signal transmitted from the new subscriber device and the local oscillator cannot be obtained.

[0071] As a result, the transmission path state estimator 16b cannot estimate the state of the optical transmission path L connecting the subscriber device 30 and the optical node device 10. Therefore, if the transmission path state estimator 16b is unable to acquire the beat component of the optical signal transmitted from the new subscriber device and the local light, it determines that the wavelength of the new subscriber device is not set properly (illegible). On the other hand, if the transmission path state estimator 16b is able to acquire the beat component of the optical signal transmitted from the new subscriber device and the local light, it determines that the wavelength of the new subscriber device is set properly (appropriate). The transmission path state estimator 16b transmits a control signal indicating the determination result to the control unit 20b. The transmission path state estimator 16b is one aspect of a wavelength confirmation unit.

[0072] The control unit 20b controls the optical node device 10b and the subscriber device 30. The control unit 20b includes a subscriber device management control unit 21 and a node control unit 22b. The node control unit 22b controls routes in the optical node device 10b and notifies the subscriber device of the wavelength assigned to the new subscriber device by the subscriber device management control unit 21 so that the subscriber device 30 can communicate with the subscriber device with which it is to communicate. For the new subscriber device, the node control unit 22b sets up an inter-port connection within the optical forwarding unit 11 so that the optical signal output from the new subscriber device is forwarded to the transmission path state estimating unit 16b.

[0073] When the node control unit 22b confirms that the determination result output from the transmission path state estimator 16b indicates that the transmission parameters are appropriate and determines the transmission parameters, the node control unit 22b sets the internal port connections of the optical forwarder 11 so that the optical signal transmitted from the new subscriber device is output to the wavelength distributor 12 that outputs the optical signal to the route assigned to the newly opened optical path. Furthermore, the node control unit 22b performs internal forwarding settings of the wavelength distributor 12 and the WXC unit 13. For example, the node control unit 22b performs route control in the optical node device 10b so that the new subscriber device can communicate with the subscriber device that is to communicate with the new subscriber device. This makes it possible to open an optical path so that the optical signal transmitted from the new subscriber device is forwarded to the subscriber device that is to communicate with the new subscriber device.

[0074] On the other hand, if the determination result output from the transmission path status estimator 16b indicates invalidity, the node control unit 22b sets the port connections of the optical forwarding unit 11 so that the optical signal transmitted from the new subscriber device is not output to any wavelength distribution unit 12. For example, the node control unit 22b maintains the port connections of the optical forwarding unit 11 so that the optical signal transmitted from the new subscriber device continues to be forwarded to the transmission path status estimator 16b, or sets the port to which the new subscriber device is connected not to be internally connected to any other port. In this way, the node control unit 22b controls the optical signal transmitted from the new subscriber device so that it does not affect the communications of other subscriber devices to which optical paths have already been opened until the set wavelength of the new subscriber device is set to an appropriate wavelength. This makes it possible to prevent an optical signal with a wavelength different from the originally assigned wavelength from being forwarded to the wavelength distribution unit 12.

[0075] (Flow of Optical Path Establishment Processing in Optical Communication System 100b) Fig. 7 is a sequence diagram showing the flow of optical path establishment processing in the optical communication system 100b in the second embodiment. Note that Fig. 7 will be described assuming that the new subscriber device is the subscriber device 30-2.

[0076] Assume that a user connects subscriber device 30-2 to the optical node device 10 via the optical transmission path L. As a result, subscriber device 30-2 is connected to the optical node device 10b via the optical transmission path L (step S201). Subscriber device 30-2 generates an upstream control signal including instructions requesting authentication, registration, etc. Subscriber device 30-2 converts the generated upstream control signal into an optical signal and transmits it as upstream control signal light. The upstream control signal light may be output from subscriber device 30-2 to the same optical transmission path as the signal light transmitted from subscriber device 30-2 to its communication partner subscriber device, or may be output to a different optical transmission path. The upstream control signal light transmitted from subscriber device 30-2 is forwarded to the control unit 20b by the optical node device 10b. When connecting a new subscriber device, an existing method may be used to forward the optical signal transmitted from the new subscriber device to the control unit 20b.

[0077] The subscriber device management control unit 21 of the control unit 20b exchanges control signal light with the subscriber device 30-2, including information necessary for authentication, registration, and optical path opening (step S202). As a result, the subscriber device management control unit 21 recognizes the new subscriber device, and instructs the subscriber device 30-2, which is the recognized new subscriber device, to allocate and set an emission wavelength so that the wavelength does not overlap with other optical paths on the transmission route. Here, the wavelength λ １ , λ ３ , λ ４ is already assigned to another subscriber unit. Therefore, the subscriber unit management control unit 21 assigns the wavelength λ 1 to the subscriber unit 30-2. ２ In this example, the subscriber unit 30-2 is assigned a wavelength λ ２ However, other wavelengths may be used as long as they do not overlap with other optical paths along the transmission route. The subscriber device management control unit 21 transmits an optical signal including an emission wavelength allocation and setting instruction to the subscriber device 30-2 via the optical node device 10b.

[0078] The subscriber device management and control unit 21 notifies the node control unit 22b of information indicating the wavelength assigned to the subscriber device 30-2. Upon receiving the notification from the subscriber device management and control unit 21, the node control unit 22b sets up a port connection within the optical forwarding unit 11 so that the optical signal output from the subscriber device 30-2 is forwarded to the transmission path state estimator 16b (step S203). Specifically, the node control unit 22b generates a switching instruction to connect the port of the optical forwarding unit 11 to which the subscriber device 30-2 is connected and the port to which the transmission path state estimator 16b is connected, and generates a control signal including the generated switching instruction and information indicating the wavelength notified by the subscriber device management and control unit 21. The node control unit 22b transmits the generated control signal to the optical node device 10b via a control line (not shown) (step S204). Note that the node control unit 22b may transmit the switching instruction and the information indicating the wavelength at different times.

[0079] The optical node device 10b receives the control signal transmitted from the control unit 20b. The optical node device 10b outputs a switching instruction included in the received control signal to the optical forwarding unit 11, and outputs information indicating the wavelength to the transmission path state estimating unit 16b. In response to the switching instruction, the optical forwarding unit 11 performs port connection switching so as to connect the port to which the subscriber device 30-2 is connected and the port to which the transmission path state estimating unit 16b is connected (step S205). In response to the information indicating the wavelength, the transmission path state estimating unit 16b changes the output wavelength of the local light source to a wavelength λ ２ Set the wavelength to a value near .

[0080] The subscriber device 30-2 receives the optical signal including the emission wavelength assignment and setting instruction transmitted from the control unit 20b. The subscriber device 30-2 receives the wavelength λ 1 specified by the emission wavelength assignment included in the received optical signal. ２ The subscriber unit 30-2 sets the set wavelength λ ２ If there is no failure or malfunction in the subscriber unit 30-2, or if the subscriber has intentionally set an incorrect wavelength, the set wavelength λ ２ On the other hand, if the subscriber unit 30-2 has a failure or malfunction, or if a subscriber intentionally sets an incorrect wavelength, the set wavelength λ ２ (e.g., wavelength λ １ Optical signals such as (e.g., optical fiber) may be transmitted.

[0081] The optical signal transmitted from the subscriber device 30-2 is input to the optical forwarding unit 11 via the optical transmission path L. The optical forwarding unit 11 outputs the input optical signal from the port to which the transmission path state estimating unit 16b is connected. As a result, the optical signal transmitted from the subscriber device 30-2 is forwarded to the transmission path state estimating unit 16b (step S207). The transmission path state estimating unit 16b estimates the state of the optical transmission path based on the optical signal forwarded by the optical forwarding unit 11 (step S208).

[0082] Specifically, the transmission path state estimation unit 16b estimates the wavelength λ set by the local light source. ２The transmission path state estimation unit 16b outputs a local light having a wavelength close to the wavelength of the input optical signal, which is then multiplexed with the input optical signal and detected. The transmission path state estimation unit 16b determines whether the wavelength of the optical signal input to the transmission path state estimation unit 16b is appropriate based on whether a beat component has been acquired as a result of the detection. In other words, it determines whether the wavelength set by the subscriber unit 30-2 is appropriate.

[0083] If the beat component is acquired, the transmission path state estimator 16b determines that the wavelength of the optical signal input to the transmission path state estimator 16b is appropriate, and if the beat component is not acquired, determines that the wavelength of the optical signal input to the transmission path state estimator 16b is incorrect. If the wavelength of the optical signal input to the transmission path state estimator 16b is appropriate, the transmission path state estimator 16b generates a control signal including a determination result that the wavelength is appropriate. If the wavelength of the optical signal input to the transmission path state estimator 16b is incorrect, the transmission path state estimator 16b generates a control signal including a determination result that the wavelength is incorrect. The transmission path state estimator 16b transmits the generated control signal to the controller 20b via a control line (not shown) (step S209).

[0084] The node control unit 22b of the control unit 20b receives the control signal transmitted from the optical node device 10b. The node control unit 22b performs control according to the determination result contained in the received control signal (step S210). Specifically, when the determination result contained in the control signal indicates that the determination result is correct, the node control unit 22b sets up an internal port connection within the optical forwarding unit 11 as shown in FIG. 8 so that the optical signal transmitted from the subscriber device 30-2 is output to the wavelength distribution unit 12 that outputs the optical signal to the route assigned to the newly opened optical path. Furthermore, the node control unit 22b performs internal forwarding settings within the wavelength distribution unit 12 and the WXC unit 13. As a result, as shown in FIG. 8, an optical path can be opened so that the optical signal transmitted from the subscriber device 30-2 is forwarded to the subscriber device with which it is communicating.

[0085] On the other hand, if the determination result included in the control signal indicates invalidity, the node control unit 22b sets the inter-port connection of the optical forwarding unit 11 so that the optical signal output from the subscriber device 30-2 is not output to any of the wavelength distribution units 12. For example, the node control unit 22b maintains the inter-port connection so that the optical signal output from the subscriber device 30-2 is continuously forwarded to the transmission path state estimation unit 16b, or performs control such as not internally connecting the port to which the subscriber device 30-2 is connected to any other port.

[0086] According to the optical communication system 100a configured as above, it is possible to obtain the same effects as those of the first embodiment.

[0087] Some of the functional units of the control units 20 and 20b in the above-described embodiments 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 may be read and executed by a computer system. Note that the term "computer system" here includes hardware such as an operating system (OS) and peripheral devices.

[0088] 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).

[0089] 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.

[0090] The present invention can be applied to a technique for opening an optical path.

[0091] DESCRIPTION OF SYMBOLS 10, 10a, 10b...Optical node device, 11...Optical transfer unit, 12...Wavelength distribution unit, 13...WXC unit, 14...Wavelength monitor unit, 15...Wavelength multiplexing / demultiplexing unit, 16b...Transmission path state estimation unit, 20, 20b...Control unit, 21...Subscriber device management and control unit, 22, 22b...Node control unit, 100, 100a...Optical communication system, 141...Wavelength tunable filter, 142...Photodetector, 143...Optical intensity measurement unit, 144...Control unit, 145...WSS, 146...AWG

Claims

1. An optical node device comprising: an optical forwarding unit that forwards optical signals transmitted from at least one newly connected new subscriber device to a specific port; and a wavelength confirmation unit that is connected to the specific port and determines whether the wavelengths of the optical signals transmitted from the one or more new subscriber devices are appropriate based on the optical signals forwarded from the optical forwarding unit.

2. The optical node device according to claim 1, wherein the wavelength confirmation unit determines whether the wavelength of the optical signal transmitted from the one or more new subscriber devices is appropriate based on the intensity of the optical signal transmitted from the optical transfer unit.

3. The optical node device according to claim 2, wherein the wavelength confirmation unit determines that the intensity of the optical signal transferred from the optical transfer unit is appropriate if it is equal to or greater than a preset threshold, and determines that the intensity of the optical signal is inappropriate if it is less than the threshold.

4. An optical node device as described in claim 2 or 3, wherein the wavelength confirmation unit is composed of: a device having the function of selectively transmitting wavelengths; one or more optical receivers that receive optical signals that have passed through the device; and a measurement unit that measures the intensity of the optical signals received by the one or more optical receivers.

5. The optical node device according to claim 1, wherein the wavelength confirmation unit determines whether the wavelength of the optical signal transmitted from the one or more new subscriber devices is appropriate by estimating the state of the optical transmission path between the one or more new subscriber devices based on the optical signal transmitted from the optical forwarding unit.

6. The optical node device according to claim 5, wherein the wavelength confirmation unit comprises a local light source that outputs local light of a wavelength close to the wavelength assigned to the new subscriber device, and when a beat component can be acquired by multiplexing and detecting the local light output from the local light source with the optical signal transferred from the optical transfer unit, the wavelength confirmation unit determines that the wavelength of the optical signal transmitted from the one or more new subscriber devices is appropriate, and when a beat component cannot be acquired, the wavelength confirmation unit determines that the wavelength of the optical signal transmitted from the one or more new subscriber devices is inappropriate.

7. An optical communication system comprising: a subscriber device management control unit that allocates wavelengths to be used for communication to at least one or more newly connected new subscriber devices; a node control unit that controls at least the connection of ports to which the new subscriber devices are connected; an optical forwarding unit that forwards optical signals transmitted from the new subscriber devices to specific ports in accordance with the control of the node control unit; and a wavelength confirmation unit that is connected to the specific port and determines whether the wavelengths of the optical signals transmitted from the one or more new subscriber devices are appropriate based on the optical signals forwarded from the optical forwarding unit.

8. A wavelength confirmation method comprising: forwarding an optical signal transmitted from at least one newly connected new subscriber device to a specific port; and determining whether the wavelength of the optical signal transmitted from the one or more new subscriber devices is appropriate based on the optical signal transmitted via the specific port.

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