Optical node device and control method for optical node device

Abstract

To provide a management device, an optical node device, an optical network system, a control method, and a non-transitory computer-readable medium that effectively suppress degradation of signal quality.SOLUTION: A management device 10 includes a path management unit 11 that manages wavelength resources available for paths in a photonics network having nodes that perform wavelength conversion by optical-analog-optical conversion and the usage status of the wavelength resources, a wavelength conversion management unit 12 that manages wavelength conversion information of paths including wavelength conversion at nodes that constitute the paths, and a control unit 13 that controls wavelength conversion at the nodes on the basis of the managed wavelength resources and usage status, and controls analog compensation at the nodes on the basis of the wavelength conversion information of the managed paths.SELECTED DRAWING: Figure 6

Description

Technical Field

[0001] The present invention relates to a management device, an optical node device, an optical network system, a control method, and a non-transitory computer-readable medium.

Background Art

[0002] In recent years, with the rapid spread of mobile terminals represented by smartphones and the high-capacity data communication such as high-definition images due to the sophistication of terminals, the traffic flowing through the network has been continuously growing rapidly. According to a certain survey, the total download traffic of broadband subscribers in Japan in 2020 was about 19 Tbps and has been increasing at an annual rate of about 57%, and further traffic growth is expected in the future. On the other hand, in the core network that supports high-capacity communication, technologies such as wavelength division multiplexing (WDM) that multiplexes optical signals of multiple different wavelengths and transmits them on a single optical fiber, advanced modulation methods such as DP-QPSK (Dual Polarization Differential Quadrature Phase Shift Keying), and 16-QAM (16-Quadrature Amplitude Modulation) have been developed to meet the needs for increased capacity. Furthermore, with the progress of 5G services in wireless communication, not only the need for increased capacity but also the need for lower network latency has been increasing. In response to these needs, in recent years, in the IOWN (Innovative Optical and Wireless Network) concept led by NTT, an all-optical network that realizes a high-capacity and low-latency network has been proposed. Unlike a network with electrical conversion in related switching nodes, an all-optical network transmits in the form of light in all paths. Therefore, not only can high-capacity communication be achieved without being restricted by the capacity of electrical switches, but also latency due to electrical conversion can be eliminated, and lower latency can be achieved.

[0003] However, in an optical fiber, since the same wavelength cannot be used, the paths of the same wavelength coming from different routes to the switching node cannot be accommodated in the same fiber, resulting in a problem that efficient path control cannot be achieved. To address this, at the switching node, a method is adopted where a wavelength converter is used to switch the wavelength and accommodate it in the same fiber.

[0004] Also, as technologies related to signal quality in an optical network, for example, Patent Documents 1 and 2 are known. Patent Document 1 discloses a PDL (Polarization Dependent Loss) compensation technique, and Patent Document 2 discloses a dispersion compensation technique.

Prior Art Documents

Patent Documents

[0005]

Patent Document 1

Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0006] However, in the related technologies so far, since wavelength conversion applied in an all - photonic network has not been considered, it is difficult to effectively suppress the deterioration of signal quality in the path.

[0007] In view of such problems, an object of the present disclosure is to provide a management device, an optical node device, an optical network system, a control method, and a non - transient computer - readable medium capable of effectively suppressing the deterioration of signal quality.

Means for Solving the Problems

[0008] The management device according to the present disclosure includes path management means for managing wavelength resources available for paths in an all-optical network including an optical node device that performs wavelength conversion by optical-analog-optical conversion and the usage status of the wavelength resources, wavelength conversion management means for managing wavelength conversion information of paths including wavelength conversion in the optical node devices constituting the paths, and control means for controlling wavelength conversion in the optical node devices based on the managed wavelength resources and usage status, and for controlling analog compensation in the optical node devices based on the managed wavelength conversion information of the paths.

[0009] The optical node device according to the present disclosure is an optical node device constituting an all-optical network, and includes optical reception means for receiving an optical signal, wavelength conversion means for performing wavelength conversion on the received optical signal by optical-analog-optical conversion, optical transmission means for transmitting the wavelength-converted optical signal, and node control means for controlling the wavelength conversion means to execute wavelength conversion and analog compensation in response to a notification from a management device that manages the all-optical network.

[0010] The optical network system according to the present disclosure includes an all-optical network including an optical node device that performs wavelength conversion by optical-analog-optical conversion, and a management device that manages the all-optical network. The management device includes path management means for managing wavelength resources available for paths in the all-optical network and the usage status of the wavelength resources, wavelength conversion management means for managing wavelength conversion information of paths including wavelength conversion in the optical node devices constituting the paths, and control means for controlling wavelength conversion in the optical node devices based on the managed wavelength resources and usage status, and for controlling analog compensation in the optical node devices based on the managed wavelength conversion information of the paths.

[0011] The control method according to the present disclosure manages wavelength resources available for a path in an all-optical network including an optical node device that performs wavelength conversion by optical-analog-optical conversion and the usage status of the wavelength resources, manages wavelength conversion information of a path including wavelength conversion in the optical node device constituting the path, controls wavelength conversion in the optical node device based on the managed wavelength resources and usage status, and controls analog compensation in the optical node device based on the managed wavelength conversion information of the path.

[0012] A non-transitory computer-readable medium storing a control program according to the present disclosure manages wavelength resources available for a path in an all-optical network including an optical node device that performs wavelength conversion by optical-analog-optical conversion and the usage status of the wavelength resources, manages wavelength conversion information of a path including wavelength conversion in the optical node device constituting the path, controls wavelength conversion in the optical node device based on the managed wavelength resources and usage status, and controls analog compensation in the optical node device based on the managed wavelength conversion information of the path, and is a non-transitory computer-readable medium storing a control program for causing a computer to execute processing.

Advantages of the Invention

[0013] According to the present disclosure, it is possible to provide a management device, an optical node device, an optical network system, a control method, and a non-transitory computer-readable medium capable of effectively suppressing deterioration of signal quality.

Brief Description of the Drawings

[0014]

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Embodiments for Carrying Out the Invention

[0015] Hereinafter, embodiments will be described with reference to the drawings. In each drawing, the same elements are denoted by the same reference numerals, and redundant explanations are omitted as necessary.

[0016] (Considerations Leading to the Embodiment) As described above, in the nodes of the all-optical network, wavelength conversion is performed as necessary by a wavelength converter. As methods of wavelength conversion, all-optical wavelength conversion using the non-linearity of light, wavelength conversion using a transponder function, etc. have been proposed or used. In all-optical wavelength conversion, since wavelength conversion is performed while keeping the light, there is an advantage of less delay, but there are problems such as large optical loss of the wavelength conversion device and limited transmission distance.

[0017] The functional block of the wavelength converter using the transponder function is shown in FIG. 1. As shown in FIG. 1, the wavelength converter 900 of the study example includes a receiver 901, a transmitter 902, and a digital signal processing unit 903. The receiver 901 receives an optical signal of a first wavelength (λ1), and after being folded back by the digital signal processing unit 903, transmits an optical signal of a second wavelength (λ2) from the transmitter 902. Thereby, the wavelength of the optical signal is converted from λ1 to λ2. In the wavelength converter 900, since complete waveform shaping is performed by so-called 3R (Re-amplification, Re-shaping, Re-timing) regeneration via the digital signal processing unit 903, the transmission distance limitation is eliminated, but there is a problem of delay occurring in the digital signal processing unit 903.

[0018] Therefore, a configuration is considered in which the analog electrical signal between the transmitter and the receiver is folded back without passing through the digital signal processing unit (hereinafter, the wavelength conversion by this configuration is referred to as O-A-O (optical-analog-optical) wavelength conversion). The functional block of this configuration is shown in FIG. 2. As shown in FIG. 2, another wavelength converter 910 of the study example includes a receiver 901 and a transmitter 902 in the same manner as the wavelength converter 900, but the digital signal processing unit 903 is not required. That is, in another wavelength converter 910, the analog electrical signal output from the receiver 901 is directly folded back to the transmitter 902 without passing through the digital signal processing unit 903.

[0019] In this configuration, since digital signal processing is not performed, it is necessary to add another function to compensate for signal degradation accumulated in the transmission paths of the conventional paths. For example, as shown in FIG. 3, an analog signal processing unit 913 is provided between the coherent reception front end 911 and the coherent transmission front end 912, and there are methods such as correcting the band.

[0020] In the example of FIG. 3, the other wavelength converter 910 includes a coherent reception front end 911, a coherent transmission front end 912, and an analog signal processing unit 913. The coherent reception front end 911 is an optical / electrical converter that coherently detects an input optical signal (λ1) based on a reference light source (local oscillator (LO) light), and outputs an analog electrical signal SA1 generated by the detection. The coherent transmission front end 912 is an electrical / optical converter that coherently modulates an analog electrical signal SA2 obtained by folding back the analog electrical signal SA1 based on a transmission light source, and outputs an output optical signal (λ2) generated by the modulation. For example, the wavelength of the output optical signal can be converted from λ1 to λ2 according to the wavelength of the transmission light source. The analog signal processing unit 913 is an analog circuit that performs analog signal processing on the analog electrical signal SA1 to compensate for the signal quality and generates the analog electrical signal SA2. The analog signal processing is an analog compensation process, for example, compensating for band degradation and the like.

[0021] Also, as shown in FIG. 3, in order to control the analog compensation process, other wavelength converters 910 may include a pre-signal monitor unit 914, a post-signal monitor unit 915, and an analog signal processing control unit 916. The pre-signal monitor unit 914 monitors the signal characteristics of the analog electrical signal SA1 before analog signal processing. The post-signal monitor unit 915 monitors the signal characteristics of the analog electrical signal SA2 after analog signal processing. The analog signal processing control unit 916 controls the operation of the analog signal processing of the analog signal processing unit 913 based on the monitoring results of the pre-signal monitor unit 914 or the post-signal monitor unit 915. For example, it monitors the bandwidth of the analog electrical signal SA1 or the analog electrical signal SA2, and controls the bandwidth adjustment amount in the analog signal processing unit 913 based on the monitoring results.

[0022] FIG. 4 shows an all-optical network using O-A-O conversion and the configuration of nodes in a study example. In FIG. 4, the network configuration is shown in a single and straight transmission line configuration for simplicity. That is, as shown in FIG. 4, the all-optical network 800 of the study example includes a plurality of nodes 810, and each node 810 is connected via an optical transmission line.

[0023] Each node 810 includes optical amplifiers 811 and 812 for compensating for transmission loss, a path switching switch 813, and an O-A-O wavelength converter pool 814 equipped with a plurality of O-A-O wavelength converters. A path switching switch 813 is connected between the optical amplifier 811 and the optical amplifier 812, and the path switching switch 813 switches the path to the O-A-O wavelength converter pool 814 as needed. After the path that requires wavelength conversion is connected to the O-A-O wavelength converter pool 814, for example, the wavelength is converted from λ1 to λ2 and sent out to the optical transmission line.

[0024] However, in existing networks, within the network range (e.g., within 10 hops), it is pre-designed such that reaching is guaranteed regardless of which wavelength is assigned to which path. However, when O-A-O wavelength conversion is installed in the network, since the signal quality changes depending on the location of wavelength conversion (where to install it from the transmitting node to the receiving node), there is a problem that it is difficult to guarantee reaching. For example, as shown in FIG. 5, when performing O-A-O wavelength conversion at node 810A, since it is close to the transmitting end 820 and the signal degradation has not progressed much, the effect of analog compensation is weak, and since the remaining transmission path is long, there is a possibility of falling below the minimum reception sensitivity in the middle. Also, when performing wavelength conversion at node 810E close to the receiving end 830, reaching up to node 810E is guaranteed, but when performing analog compensation on a signal with a deteriorated S / N ratio that has progressed, there is a possibility of further promoting S / N degradation and falling below the minimum reception sensitivity.

[0025] Also, there are devices with wavelength characteristics such as optical amplifiers in the network. For example, NF (Noise Figure) has a characteristic that the characteristics are poor on the short-wavelength side. For this reason, the characteristics may change depending on the wavelength before wavelength conversion and the wavelength after wavelength conversion during wavelength conversion. For example, when converting from a short wavelength to a short wavelength, there is a possibility that the characteristics become worse compared to when converting from a long wavelength to a long wavelength.

[0026] As described above, as related technologies, in Patent Document 1, an analog PDL compensation technology, in Patent Document 2, an analog dispersion compensation technology, etc. are disclosed. Thus, many analog compensation technologies have been disclosed so far. However, the analog compensation technologies so far have not been designed on the premise that O-A-O wavelength conversion is arranged, and it is necessary to separately consider network control considering the above-mentioned location of wavelength conversion. Therefore, the embodiments are made in view of the above problems.

[0027] Specifically, two main problems can be considered. The first problem is that in an all-optical network using O-A-O wavelength conversion, it is difficult to guarantee the reach of a path. The reason is that the signal quality changes depending on the location of wavelength conversion (where to install it from the transmitting node to the receiving node). The second problem is that in an all-optical network using O-A-O wavelength conversion, it is not possible to equalize the guarantee of path reach. The reason is that there are devices with wavelength characteristics such as optical amplifiers, and the quality of the path depends on the wavelengths before and after wavelength conversion. Therefore, in the embodiment, a control method in an optical network using analog wavelength conversion is provided, and in particular, a method for ensuring the reach guarantee of a path is provided.

[0028] (Overview of the Embodiment) FIG. 6 shows the schematic configuration of the management device according to the embodiment, and FIG. 7 shows the schematic configuration of the node according to the embodiment.

[0029] Node 20 is an optical node device that performs wavelength conversion by O-A-O conversion (optical-analog-optical conversion), and constitutes an all-optical network. The management device 10 manages and controls the all-optical network including the node 20. For example, the management device 10 is an NMS (Network Management System) that manages the network.

[0030] As shown in FIG. 6, the management device 10 includes a path management unit 11, a wavelength conversion management unit 12, and a control unit 13. The path management unit 11 manages the wavelength resources available for paths in the all-optical network and the usage status of the wavelength resources. The path management unit 11 is, for example, a path database that manages and holds wavelength resources (information) and usage status (information).

[0031] The wavelength conversion management unit 12 manages the wavelength conversion information of paths including wavelength conversion in the node 20 that constitutes the path. The wavelength conversion management unit 12 is, for example, a wavelength conversion management database that manages and holds the wavelength conversion information of the path.

[0032] Based on the wavelength resources and usage status managed by the path management unit 11, the control unit 13 controls the wavelength conversion in the node 20, and based on the wavelength conversion information of the paths managed by the wavelength conversion management unit 12, controls the analog compensation in the node 20. For example, the control unit 13 may control the node 20 to perform analog compensation for all paths that have been wavelength-converted in the path before the node 20 by notifying the wavelength conversion information of the path to the node 20.

[0033] Furthermore, wavelength conversion characteristic information including the transmission distance before wavelength conversion, the transmission distance after wavelength conversion, the estimated signal degradation degree, and the analog compensation node identification information may be further managed. In this case, the control unit 13 may determine candidates for paths to perform analog compensation based on the wavelength conversion characteristic information, and control the node 20 to perform analog compensation for the determined paths. Furthermore, the control unit 13 may divide the entire wavelength band into a plurality of parts and control the wavelength conversion so that the NF (Noise Figure) characteristics are averaged.

[0034] As shown in FIG. 7, the node 20 includes an optical reception unit 21, a wavelength conversion unit 22, an optical transmission unit 23, and a node control unit 24. The optical reception unit 21 receives an optical signal from the optical transmission path. The wavelength conversion unit 22 wavelength-converts the optical signal received by the optical reception unit 21 by O-A-O wavelength conversion. The optical transmission unit 23 transmits the optical signal wavelength-converted by the wavelength conversion unit 22 to the optical transmission path.

[0035] The node control unit 24 controls the wavelength conversion unit 22 to perform wavelength conversion and analog compensation in response to a notification from the management device 10. For example, the node control unit 24 may monitor all paths that have been wavelength-converted in the path before its own node 20 according to the wavelength conversion information of the path notified from the management device 10, and control the analog compensation based on the monitoring result. Also, the node control unit 24 may control the analog compensation for the corresponding path based on the information of the path to be analog-compensated notified from the management device 10.

[0036] With such a configuration, in an all-optical network using O-A-O wavelength conversion, the degradation of the signal quality of a path can be effectively suppressed. That is, as the first effect, by appropriately performing analog compensation at the node in the path where wavelength conversion has been performed, it becomes possible to guarantee the reach of the path. Further, as the second effect, by performing wavelength conversion so that the NF characteristics are averaged, it becomes possible to equalize the reach guarantee of the path.

[0037] (Embodiment 1) Next, Embodiment 1 will be described. In this embodiment, an example will be described in which at a node, all paths wavelength-converted in the path before the node are monitored and analog compensation is performed.

[0038] (System Configuration) First, the configuration of this embodiment will be described with reference to FIGS. 8 and 9. FIG. 8 shows a configuration example of an optical network system according to this embodiment. As shown in FIG. 8, the optical network system 1 according to this embodiment includes an NMS 100 and a plurality of nodes 200. Between the plurality of nodes 200, they are optically communicably connected via an optical transmission line 300. Between the plurality of nodes 200 and the NMS 100, they are also connected via, for example, the optical transmission line 300, but they may be communicably connected by any other transmission line.

[0039] The plurality of nodes 200 are optical communication devices that perform O-A-O wavelength conversion. That is, the plurality of nodes 200 constitute an all-optical network 2 using O-A-O wavelength conversion. In the example of FIG. 8, the plurality of nodes 200 constitute a mesh-shaped network, but they may constitute a network in another form such as a ring shape. Further, the plurality of nodes 200 constitute a path from a transmission node (transmission end) to a reception node (reception end) according to the control from the NMS 100, and transmit data (optical signal) on the path of the path.

[0040] The NMS100 is a management device that manages and controls an all-optical network 2 including a plurality of nodes 200. The NMS100 manages and controls the paths configured by the nodes 200 in the all-optical network 2. The NMS100 manages the path and wavelength from the transmitting node to the receiving node, and sets the path and wavelength for the nodes 200 on the path.

[0041] FIG. 9 shows a configuration example of each device in the optical network system according to the present embodiment. As shown in FIG. 9, the NMS100 includes a path database (DB) 101, a wavelength conversion management database (DB) 102, and a network control unit 103.

[0042] The path database 101 manages the paths formed by the plurality of nodes 200 in the all-optical network 2, and manages and holds the wavelength resources (wavelength resource information) available for the paths and the usage status (usage status information) of the wavelength resources. The path database 101 holds the wavelength resources and usage status at each node 200 constituting the path. The wavelength resources (wavelength resource information) indicate all the wavelengths available for the path, and the usage status (usage status information) indicates the wavelengths used for the path.

[0043] The wavelength conversion management database 102 manages and holds the wavelength conversion by the nodes 200 constituting the path. The wavelength conversion management database 102 holds the wavelength conversion information at each node 200 constituting the path. The wavelength conversion information is information that can identify the wavelength conversion at each node 200 on the path of the path. For example, it may indicate the presence or absence of wavelength conversion at each node 200, or may indicate the wavelengths before and after conversion at each node.

[0044] The network control unit 103 refers to the path database 101 and the wavelength conversion management database 102, and controls the path and the nodes 200 that constitute the path. The network control unit 103 performs wavelength conversion for paths that require wavelength conversion based on the wavelength resources and usage status in the path database 101. That is, the network control unit 103 instructs each node 200 on the path to perform wavelength conversion of the path as necessary, and holds the wavelength conversion information indicating the result of the wavelength conversion in the wavelength conversion management database 102. In addition, the network control unit 103 notifies all nodes 200 of the wavelength conversion information of all paths in the wavelength conversion management database 102.

[0045] In addition, the node 200 includes a transmission loss compensation optical amplifier 201 (201a and 201b), an optical switch (SW) 202, a node loss compensation optical amplifier 203 (203a and 203b), a wavelength selective switch (WSS) 204 (204a and 204b), a tap coupler 205, an optical path monitor 206, an analog wavelength converter pool 210, and a node controller 207.

[0046] The transmission loss compensation optical amplifier 201 is an optical amplifier that compensates for the transmission loss occurring in the optical fiber by amplifying the optical signal. The transmission loss compensation optical amplifier 201a is a receiving amplifier that receives the optical signal. The transmission loss compensation optical amplifier 201a receives the optical signal in fiber units from the adjacent node on the transmitting node side via the input optical fiber 300a, and compensates for the transmission loss of the input optical fiber 300a in fiber units. The transmission loss compensation optical amplifier 201a outputs the optical signal after the transmission loss compensation to the optical switch 202.

[0047] The transmission loss compensation optical amplifier 201b is a transmitting amplifier that transmits the optical signal. The transmission loss compensation optical amplifier 201b compensates for the transmission loss of the optical signal from the optical switch 202 in fiber units. The transmission loss compensation optical amplifier 201b outputs the optical signal in fiber units after the transmission loss compensation to the adjacent node on the receiving node side via the output optical fiber 300b.

[0048] The optical switch 202 is an optical switch capable of switching the path of an optical signal in wavelength units. The optical switch 202 is connected between the reception - side transmission - loss - compensating optical amplifier 201a and the transmission - side transmission - loss - compensating optical amplifier 201b. The optical switch 202 switches the add / drop of a predetermined optical signal (path) in response to control from the node controller 207. The optical switch 202 performs switching in wavelength units on the fiber - unit optical signal from the transmission - loss - compensating optical amplifier 201a, and outputs the optical signal of the wavelength to be dropped to the node - loss - compensating optical amplifier 203a via the wavelength - conversion port. Also, the optical switch 202 receives an optical signal via the analog wavelength - converter pool 210 from the node - loss - compensating optical amplifier 203b through the wavelength - conversion port, performs switching in wavelength units on the received fiber - unit optical signal, and outputs the optical signal of the wavelength to be added to the transmission - loss - compensating optical amplifier 201b.

[0049] The node - loss - compensating optical amplifier 203 is an optical amplifier that compensates for the loss occurring in the node by amplifying the optical signal. The reception - side (drop - side) node - loss - compensating optical amplifier 203a compensates for the loss of the fiber - unit optical signal from the wavelength - conversion port of the optical switch 202, and outputs the loss - compensated optical signal to the wavelength switch 204a. The transmission - side (add - side) node - loss - compensating optical amplifier 203b compensates for the loss of the fiber - unit optical signal from the wavelength switch 204b via the analog wavelength - converter pool 210, and outputs the loss - compensated optical signal to the wavelength - conversion port of the optical switch 202.

[0050] The wavelength switch 204 is an optical switch capable of switching the path of an optical signal in wavelength units. The reception - side wavelength switch 204a separates the fiber - unit optical signal from the node - loss - compensating optical amplifier 203a in wavelength units, and outputs the separated optical signal to the O - A - O wavelength converter 211 of the analog wavelength - converter pool 210. The transmission - side wavelength switch 204b bundles the wavelength - unit optical signals from the O - A - O wavelength converter 211 of the analog wavelength - converter pool 210 in fiber units, and outputs the fiber - unit optical signal to the node - loss - compensating optical amplifier 203b.

[0051] The tap coupler 205 taps part or all of the optical signals in wavelength units output from the receiving-side wavelength switch 204a. The optical path monitor 206 monitors the quality of the optical signals tapped by the tap coupler 205. In response to the control from the node controller 207, the tap coupler 205 taps a predetermined optical signal, and the optical path monitor 206 monitors the tapped optical signal.

[0052] The analog wavelength converter pool 210 includes a plurality of O-A-O wavelength converters 211. A plurality of O-A-O wavelength converters 211 are provided corresponding to the wavelength of the input optical signal and the wavelength of the output optical signal. The O-A-O wavelength converter 211 is a wavelength converter capable of performing O-A-O wavelength conversion and analog compensation. The O-A-O wavelength converter 211 includes, for example, a coherent reception front end, a coherent transmission front end, and an analog signal processing unit (analog compensator) as shown in FIG. 3, but other configurations may be used as long as O-A-O wavelength conversion is possible. The O-A-O wavelength converter 211 performs analog compensation, or wavelength conversion and analog compensation, on the optical signals in wavelength units from the wavelength switch 204a in response to the control from the node controller 207, and outputs the optical signals subjected to wavelength conversion or analog compensation to the wavelength switch 204b.

[0053] For example, as an analog compensator in the O-A-O wavelength converter 211, a compensator that performs band compensation, PDL compensation, dispersion compensation, etc. is installed. Also, the optical path monitor 206 varies depending on the configuration of the analog compensator. For example, a spectrum analyzer is used when performing band compensation, a PDL monitor is used when performing PDL compensation, and a dispersion monitor is used when performing dispersion compensation.

[0054] The node controller 207 controls each device within the node 200. The node controller 207 controls the operation of each device in response to the control from the NMS 100. When the node controller 207 receives an instruction for wavelength conversion from the NMS 100, it controls the optical switch 202 to switch the corresponding wavelength and controls the O-A-O wavelength converter 211 to convert the wavelength. Further, when the node controller 207 receives wavelength conversion information for all paths from the NMS 100, it determines the paths (wavelengths) to be monitored, and based on the results monitored by the tap coupler 205 and the optical path monitor 206, controls the analog compensation of the corresponding O-A-O wavelength converter 211.

[0055] <System operation> Next, with reference to FIGS. 8 and 9 and using FIG. 10, the operation of the present embodiment will be described. FIG. 10 is a flowchart showing an operation example of the optical network system according to the present embodiment.

[0056] As shown in FIG. 10, first, the NMS 100 performs wavelength conversion of paths (S101). When a path request is issued, the NMS 100 refers to the path database 101, determines the paths that require wavelength conversion based on the wavelength resources and usage status, and notifies the nodes 200 that perform wavelength conversion of the information on the determined paths. For example, it notifies information for identifying the paths, the wavelength before conversion, the wavelength after conversion, and the like. The node controller 207 of each node 200 controls the optical switch 202 and the O-A-O wavelength converter 211 to convert the wavelength of the corresponding path based on the information received from the NMS 100. Further, when each node 200 performs wavelength conversion, the NMS 100 holds the wavelength conversion information of the paths indicating that each node 200 has performed wavelength conversion in the wavelength conversion management database 102.

[0057] Next, NMS100 notifies the wavelength conversion information of all paths (S102). When the wavelength conversion and the update of the wavelength conversion management database 102 are completed, NMS100 refers to the wavelength conversion management database 102 and notifies the wavelength conversion information of all the paths that have been wavelength-converted to the node controllers 207 of all the nodes 200.

[0058] Next, each node 200 performs a drop setting for the path (S103). At each node 200, when receiving the wavelength conversion information of all paths from NMS100, the node controller 207 determines the path (wavelength) to be dropped based on the wavelength conversion information of all paths. The path to be dropped is the path (analog compensation candidate) to be monitored. Specifically, from the wavelength conversion information of the path, the paths that have been wavelength-converted by other nodes 200 in the path before the own node (before the own node) are extracted, and the optical switch 202 is set to drop all the extracted paths (wavelengths).

[0059] Next, each node 200 connects the wavelength switch 204a to the O-A-O wavelength converter 211 (S104). At each node 200, the node controller 207 sets the wavelength switch 204a so that the dropped path (wavelength), that is, all the paths that have been wavelength-converted in the path before the own node, are connected to the O-A-O wavelength converter 211 after demultiplexing.

[0060] Next, each node 200 monitors the path (S105). At each node 200, the optical path monitor 206 connected to the tap coupler 205 monitors the quality of the dropped path (wavelength), that is, all the paths that have been wavelength-converted in the path before the own node.

[0061] Next, each node 200 performs analog compensation based on the monitoring result of the path (S106). At each node 200, the node controller 207 determines whether the quality of the monitored path exceeds a predetermined degradation threshold. If there is a path that exceeds the degradation threshold, analog compensation (or wavelength conversion and analog compensation) is performed in the O-A-O wavelength converter 211 to which the corresponding path is connected. That is, for a path whose quality has deteriorated below a predetermined threshold, analog compensation is performed in the O-A-O wavelength converter 211, and for a path whose quality has not deteriorated below the predetermined threshold, analog compensation is not performed in the O-A-O wavelength converter 211. Note that the amount of analog compensation may be adjusted according to the amount of degradation of the path quality.

[0062] Next, each node 200 performs an add setting for the path (S107) and completes the operation (setting) (S108). At each node 200, when analog compensation is performed according to the monitoring result, the node controller 207 sets the optical switch 202 and the wavelength switch 204b so that the dropped path (wavelength), that is, the path for which analog compensation has been performed according to the monitoring result, is added to the original fiber. Note that the same operation is performed at the next-stage node 200 as well.

[0063] As described above, in this embodiment, in the all-optical network using O-A-O wavelength conversion, the NMS refers to the path database that manages the wavelength resources and usage status in the NMS, notifies the node of the information of the path that requires wavelength conversion to perform wavelength conversion, and retains data in the wavelength conversion management database. The NMS refers to the wavelength conversion management database and notifies the node controllers of all nodes of the wavelength conversion information of all the paths that have been wavelength-converted. At each node, all the paths that have been wavelength-converted in the path before its own node are dropped, and the signal quality is monitored. Based on the monitoring information, for the paths that exceed a predetermined degradation threshold, each node performs analog compensation (or wavelength conversion and analog compensation) in the O-A-O wavelength converter. In this way, by monitoring the signal quality of the wavelength-converted paths and performing analog compensation according to the degradation status, it is possible to guarantee the reach of the paths.

[0064] (Embodiment 2) Next, Embodiment 2 will be described. In this embodiment, an example of determining the paths for which the NMS performs analog compensation will be described.

[0065] <System Configuration> First, the configuration of this embodiment will be described with reference to FIG. 11. FIG. 11 shows a configuration example of each device in the optical network system according to this embodiment. Here, only the differences from the configuration in Embodiment 1 will be described, and the description of the same configuration will be omitted.

[0066] In this embodiment, the signal quality of the paths is not monitored at each node 200. Therefore, in the node 200, the tap coupler 205 and the optical path monitor 206 in Embodiment 1 are omitted.

[0067] In addition to the configuration of Embodiment 1, the NMS 100 includes a wavelength conversion characteristic database 104 (DB). The wavelength conversion characteristic database 104 stores wavelength conversion characteristic information indicating the wavelength conversion characteristics of the paths. The wavelength conversion characteristic information includes the transmission distance (A) before wavelength conversion, the transmission distance (B) after wavelength conversion, the estimated signal degradation degree (C), and the analog compensation (band recompensation) node number (D). The wavelength conversion characteristic information preferably includes all of the transmission distance (A) before wavelength conversion, the transmission distance (B) after wavelength conversion, the estimated signal degradation degree (C), and the analog compensation node number (D), but may include at least any one of the information. For example, it may include the estimated signal degradation degree (C) and the analog compensation node number (D).

[0068] The transmission distance (A) before wavelength conversion is the transmission distance (e.g., number of hops) from the transmission end to the node where wavelength conversion is performed in the path. The transmission distance (B) after wavelength conversion is the transmission distance from the node where wavelength conversion is performed to the reception end in the path. The estimated signal degradation degree (C) is the degradation degree of the optical signal estimated in the path. The degradation degree is the degradation degree of the optical signal received at the reception end with respect to the optical signal transmitted from the transmission end. For example, the degradation degree can be estimated from the transmission distance (A) before wavelength conversion and the transmission distance (B) after wavelength conversion. The analog compensation node number (D) is the number (identification information) of the node that performs analog compensation in the path. The wavelength conversion characteristic information stored in the wavelength conversion characteristic database 104 may be set based on the wavelength conversion information of the path stored in the wavelength conversion management database 102. Also, the wavelength conversion characteristic information is map information obtained by mapping each piece of information. Specifically, the path of the path is shown on a network map indicating the connection relationship of each node in the network, and for each path, the transmission distance (A) before wavelength conversion, the transmission distance (B) after wavelength conversion, the estimated signal degradation degree (C), and the analog compensation node number (D) are shown.

[0069] <System Operation> Next, with reference to FIGS. 6 and 11 and using FIG. 12, the operation of this embodiment will be described. FIG. 12 is a flowchart showing an operation example of the optical network system according to this embodiment.

[0070] As shown in FIG. 12, first, the NMS 100 performs wavelength conversion of a path (S201). Similar to the first embodiment, when a path request is issued, the NMS 100 refers to the path database 101 that manages wavelength resources and usage status, notifies the node 200 of information on paths that require wavelength conversion to perform wavelength conversion, and holds the wavelength conversion information of the path in the wavelength conversion management database 102.

[0071] Next, the NMS 100 creates a wavelength conversion characteristic database 104 (S202). By creating the wavelength conversion characteristic database 104, the NMS 100 selects in advance paths that are assumed to be deteriorating. Specifically, map information (wavelength conversion characteristic information) obtained by mapping the transmission distance (A) before wavelength conversion, the transmission distance (B) after wavelength conversion, the estimated signal degradation degree (C), and the analog compensation node number (D) is generated, and the map information is held in the wavelength conversion characteristic database 104. For example, for each path, the transmission distance (A) before wavelength conversion and the transmission distance (B) after wavelength conversion are obtained from the wavelength conversion information (route and wavelength conversion node) of the path, and the estimated signal degradation degree (C) is obtained from the transmission distance (A) before wavelength conversion and the transmission distance (B) after wavelength conversion. A node that performs analog compensation is selected from nodes that can perform analog compensation on the path, and the analog compensation node number (D) is specified. The NMS 100 refers to the wavelength conversion characteristic database 104 and determines candidates for paths to perform analog compensation according to the map information. For example, based on the estimated signal degradation degree (C) of the path, the path to be subjected to analog compensation is determined. Taking a specific example, assuming that the number of hops to guarantee reachability is 10, and for path 1 (A = 1, B = 9, C = 5, D = 8) and path 2 (A = 7, B = 3, C = 6, D = 9), if C = 5 or more is set as the analog compensation target, then path 1 and path 2 are determined to be the analog compensation targets.

[0072] Next, NMS100 notifies the information of the path to be analog-compensated (S203). NMS100 notifies the wavelength conversion information (wavelength conversion management database 102) of the determined path to be analog-compensated and the wavelength conversion characteristic information (wavelength conversion characteristic database 104) of the path to the node 200 that performs analog compensation. In the above specific example, since the analog compensation node number (D) of path 1 is 8, the information of path 1 is notified to node 200 with node number 8, and since the analog compensation node number (D) of path 2 is 9, the information of path 2 is notified to node 200 with node number 9.

[0073] Next, the notified node 200 performs a drop setting for the path (S204). When the node 200 receives the information of the path to be analog-compensated from NMS100, the node controller 207 sets the optical switch 202 so as to drop the notified path (wavelength) to be analog-compensated.

[0074] Next, the node 200 connects the wavelength switch 204a to the O-A-O wavelength converter 211 (S205). In the node 200, the node controller 207 sets the wavelength switch 204a so that the path to be analog-compensated with the drop setting is connected to the O-A-O wavelength converter 211 after demultiplexing.

[0075] Next, the node 200 performs analog compensation for the corresponding path (S206). In the node 200, for the corresponding path connected to the O-A-O wavelength converter 211, the O-A-O wavelength converter 211 performs analog compensation (or wavelength conversion and analog compensation).

[0076] Next, the node 200 performs an add setting for the path (S207) and completes the operation (setting) (S208). In the node 200, when analog compensation is performed for the path to be analog-compensated, the node controller 207 sets the optical switch 202 and the wavelength switch 204b so that the dropped path (wavelength) is added to the original fiber. Note that this operation is performed only by the node 200 that has received the notification from NMS100.

[0077] As described above, in this embodiment, in an all-optical network using O-A-O wavelength conversion, as another method of performing analog compensation, a wavelength conversion characteristic database in which the transmission distance before wavelength conversion, the transmission distance after wavelength conversion, the estimated signal degradation degree, and the analog compensation node number are mapped is created and held, and candidates for paths for performing analog compensation are determined according to the map, and analog compensation is performed only for the paths. In this way, by calculating in advance the signal quality of the wavelength-converted path and performing analog compensation according to the degradation situation, it is possible to guarantee the reach of the path.

[0078] (Embodiment 3) Next, Embodiment 3 will be described. Since the configuration in this embodiment may be either Embodiment 1 or Embodiment 2, the description of the configuration will be omitted.

[0079] <System Operation> Next, with reference to FIGS. 8 and 9 and using FIGS. 13 and 14, the operation of this embodiment will be described. FIG. 13 is a flowchart showing the operation of the optical network system according to this embodiment.

[0080] As shown in FIG. 13, first, the NMS 100 performs wavelength conversion of a path in consideration of wavelength characteristics (S301). When a path request is issued, the NMS 100 refers to the path database 101 that manages wavelength resources and usage status, notifies the node 200 of information on paths that require wavelength conversion to perform wavelength conversion, and holds the wavelength conversion information of the paths in the wavelength conversion management database 102.

[0081] At this time, NMS100 performs wavelength conversion in consideration of the wavelength characteristics of devices in the network. For example, the wavelength characteristics are the NF characteristics of the optical amplifier mounted on node 200. The NF characteristics of the optical amplifier are characterized in that the characteristics on the short wavelength side are inferior to those on the long wavelength side. FIG. 14 is a conceptual diagram showing the NF characteristics and the wavelength allocation algorithm. For example, the entire wavelength band is divided into 10 equal parts, and wavelength conversion is performed so that the NF characteristics are averaged based on the wavelength band. In one example, at node 200, by controlling the conversion of wavelength band 1 to wavelength band 10, wavelength band 4 to wavelength band 5, etc., the NF characteristics can be averaged. That is, the wavelength is converted between wavelength bands where the amount of decrease (deterioration amount) with respect to the average value and the amount of increase (improvement amount) with respect to the average value are equal (the absolute values are equal). Since the operations after S102 are the same as those in Embodiment 1, the description thereof is omitted.

[0082] As described above, in this embodiment, wavelength conversion may be performed in consideration of the wavelength characteristics of devices in the network. For example, the entire wavelength band may be divided into a plurality of parts, and wavelength conversion may be performed so that the NF characteristics are averaged. In this way, by performing wavelength conversion in consideration of characteristics such as NF, the quality of the path is made uniform, and it is possible to reduce the paths that require analog compensation.

[0083] Note that the present disclosure is not limited to the above-described embodiment, and can be appropriately changed without departing from the gist thereof.

[0084] Each configuration in the above-described embodiment is configured by hardware or software, or both, and may be configured by one piece of hardware or software, or may be configured by a plurality of pieces of hardware or software. Each device and each function (processing) may be realized by a computer 30 having a processor 31 such as a CPU (Central Processing Unit) and a memory 32 which is a storage device, as shown in FIG. 15. For example, a program for performing the method (management method and control method) in the embodiment may be stored in the memory 32, and each function may be realized by the processor 31 executing the program stored in the memory 32.

[0085] These programs, when loaded into a computer, include a set of instructions (or software code) for causing the computer to perform one or more functions described in the embodiments. The programs may be stored in a non-transitory computer-readable medium or a tangible storage medium. By way of example and not limitation, the computer-readable medium or tangible storage medium includes random-access memory (RAM), read-only memory (ROM), flash memory, solid-state drive (SSD), or other memory technologies, CD-ROM, digital versatile disc (DVD), Blu-ray (registered trademark) disc, or other optical disc storage, magnetic cassette, magnetic tape, magnetic disk storage, or other magnetic storage devices. The programs may also be transmitted on a transitory computer-readable medium or a communication medium. By way of example and not limitation, the transitory computer-readable medium or communication medium includes electrical, optical, acoustic, or other forms of propagated signals.

[0086] As described above, the present disclosure has been described with reference to the embodiments, but the present disclosure is not limited to the above embodiments. Various changes that can be understood by those skilled in the art can be made to the configuration and details of the present disclosure within the scope of the present disclosure.

[0087] Some or all of the above embodiments may be described as follows, but are not limited thereto. (Appendix 1) Path management means for managing wavelength resources usable for a path in an all-optical network provided with an optical node device that performs wavelength conversion by optical-analog-optical conversion and the usage status of the wavelength resources; Wavelength conversion management means for managing wavelength conversion information of a path including wavelength conversion in the optical node device constituting the path; Control means for controlling wavelength conversion in the optical node device based on the managed wavelength resources and usage status, and for controlling analog compensation in the optical node device based on the wavelength conversion information of the managed path; A management device comprising the same. (Appendix 2) The control means controls the optical node device in the path to perform analog compensation for all paths wavelength-converted in the path before the optical node device by notifying the wavelength conversion information of the path to the optical node device. The management device according to Appendix 1. (Appendix 3) It comprises wavelength conversion characteristic management means for managing wavelength conversion characteristic information indicating the wavelength conversion characteristics of the path. The control means determines candidates for paths to perform analog compensation based on the wavelength conversion characteristic information, and controls the optical node device to perform analog compensation for the determined paths. The management device according to Appendix 1. (Appendix 4) The wavelength conversion characteristic information includes the transmission distance before wavelength conversion in the path, the transmission distance after wavelength conversion in the path, the estimated signal degradation degree of the path, and the identification information of the node for performing analog compensation in the path. The management device according to Appendix 3. (Appendix 5) The control means divides the entire wavelength band into a plurality of parts, and controls the wavelength conversion so that the NF (Noise Figure) characteristics are averaged. The management device according to any one of Appendices 1 to 4. (Appendix 6) An optical node device constituting an all-optical network, Optical receiving means for receiving an optical signal; Wavelength conversion means for wavelength-converting the received optical signal by optical-analog-optical conversion; Optical transmitting means for transmitting the wavelength-converted optical signal; Node control means for controlling the wavelength conversion means to perform wavelength conversion and analog compensation in response to a notification from a management device that manages the all-optical network; An optical node device comprising the same. (Appendix 7) Comprising a monitoring means for monitoring an optical signal input to the wavelength conversion means; The node control means monitors, by the monitoring means, all paths that have been wavelength-converted in a path including the own device and in a path before the own device based on the wavelength conversion information of the path notified from the management device, and controls to perform analog compensation based on the monitoring result. The optical node device according to Appendix 6. (Appendix 8) The node control means controls to perform analog compensation on a path among the monitored paths whose quality has deteriorated below a predetermined threshold value. The optical node device according to Appendix 7. (Appendix 9) The node control means controls to perform analog compensation on a corresponding path based on information on the path to be analog-compensated notified from the management device. The optical node device according to Appendix 6. (Appendix 10) An all-optical network comprising an optical node device that performs wavelength conversion by optical-analog-optical conversion, and a management device that manages the all-optical network; The management device: Path management means for managing wavelength resources available for paths in the all-optical network and the usage status of the wavelength resources; Wavelength conversion management means for managing wavelength conversion information of paths including wavelength conversion in the optical node devices constituting the paths; Control means for controlling wavelength conversion in the optical node device based on the managed wavelength resources and usage status, and controlling analog compensation in the optical node device based on the managed wavelength conversion information of the paths; An optical network system comprising the same. (Appendix 11) Managing wavelength resources available for a path in an all-optical network provided with an optical node device that performs wavelength conversion by optical-analog-optical conversion and the usage status of the wavelength resources, managing wavelength conversion information of a path including wavelength conversion in the optical node device constituting the path, controlling wavelength conversion in the optical node device based on the managed wavelength resources and usage status, and controlling analog compensation in the optical node device based on the wavelength conversion information of the managed path, Control method. (Appendix 12) Managing wavelength resources available for a path in an all-optical network provided with an optical node device that performs wavelength conversion by optical-analog-optical conversion and the usage status of the wavelength resources, managing wavelength conversion information of a path including wavelength conversion in the optical node device constituting the path, controlling wavelength conversion in the optical node device based on the managed wavelength resources and usage status, and controlling analog compensation in the optical node device based on the wavelength conversion information of the managed path, A non-transitory computer-readable medium storing a control program for causing a computer to execute processing. (Appendix 13) A control method in an all-photonic network using analog wavelength conversion that directly connects the analog signal output of an optical receiver to the analog signal input of an optical transmitter to perform wavelength conversion, The NMS includes a path database that manages wavelength resources and usage status, and a wavelength management database that manages wavelength conversion information, A path control method characterized by performing wavelength conversion based on the path database and performing analog compensation with reference to the wavelength conversion management database. (Appendix 14) In a node on a communication path, referring to the information in the wavelength conversion management base, monitoring all paths that have been wavelength-converted in the path before the own node, and performing analog compensation based on the monitoring information. The path control method according to Appendix 13. (Appendix 15) The NMS includes a wavelength conversion characteristic database that holds the transmission distance before wavelength conversion, the transmission distance after wavelength conversion, the estimated signal degradation degree, and the analog compensation node number, determines candidates for paths for which analog compensation is to be performed by referring to the wavelength conversion characteristic database, and performs analog compensation only for said paths. The path control method according to Appendix 13, characterized in that. (Appendix 16) The path control method according to any one of Appendices 13 to 14, characterized in that the entire wavelength band is divided into a plurality of parts and the wavelength conversion is performed so that the NF characteristics are averaged. (Appendix 17) A network management system characterized by comprising the path control method according to Appendix 13. (Appendix 18) An optical network device characterized by comprising the path control method according to Appendix 13. (Appendix 19) An optical network control program characterized by comprising the path control method according to Appendix 13.

Explanation of Signs

[0088] 1 Optical network system 2 All-Photonic Network 10 Management device 11 Path management section 12 Wavelength conversion management section 13 Control section 20 Node 21 Optical reception section 22 Wavelength conversion section 23 Optical transmission section 24 Node control section 30 Computer 31 Processor 32 Memory 100 NMS 101 Path database 102 Wavelength conversion management database 103 Network control section 104 Wavelength conversion characteristic database 200 Node 201 Transmission Loss Compensation Optical Amplifier 202 Optical Switch 203 Node Loss Compensation Optical Amplifier 204 Wavelength Switch 205 Tap Coupler 206 Optical Path Monitor 207 Node Controller 210 Analog Wavelength Converter Pool 211 O-A-O Wavelength Converter 300 Optical Transmission Line 300a, 300b Optical Fiber

Claims

1. Path management means for managing wavelength resources available for use in a path in an all-optical network provided with an optical node device that performs wavelength conversion by optical-analog-optical conversion, and the usage status of the wavelength resources; Wavelength conversion management means for managing wavelength conversion information of a path including wavelength conversion in the optical node device constituting the path; Control means for controlling wavelength conversion in the optical node device based on the managed wavelength resources and usage status, and controlling analog compensation in the optical node device based on the managed wavelength conversion information of the path; A management device comprising the above.

2. The control means controls the optical node device in the path to perform analog compensation for all paths wavelength-converted in a path previous to the optical node device by notifying the optical node device of the wavelength conversion information of the path. The management device according to Claim 1.

3. Comprising wavelength conversion characteristic management means for managing wavelength conversion characteristic information indicating the wavelength conversion characteristics of the path; The control means determines candidates for paths to perform analog compensation based on the wavelength conversion characteristic information, and controls the optical node device to perform analog compensation for the determined paths. The management device according to Claim 1.

4. The wavelength conversion characteristic information includes the transmission distance before wavelength conversion in the path, the transmission distance after wavelength conversion in the path, the estimated signal degradation degree of the path, and identification information of a node that performs analog compensation in the path. The management device according to Claim 3.

5. The control means divides the entire wavelength band into a plurality of parts, and controls the wavelength conversion so that the NF (Noise Figure) characteristics are averaged. The management device according to any one of Claims 1 to 4.

6. An optical node device constituting an all-optical network, Optical reception means for receiving an optical signal; Wavelength conversion means for wavelength-converting the received optical signal by optical-analog-optical conversion; Optical transmission means for transmitting the wavelength-converted optical signal; Node control means for controlling the wavelength conversion means to perform wavelength conversion and analog compensation in response to a notification from a management device that manages the all-optical network. An optical node device comprising the above.

7. Comprising monitoring means for monitoring an optical signal input to the wavelength conversion means. The node control means monitors, by the monitoring means, all paths that are paths including the own device and are wavelength-converted in a path before the own device based on the wavelength conversion information of the path notified from the management device, and controls to perform analog compensation based on the monitoring result. The optical node device according to claim 6.

8. An all-optical network including an optical node device that performs wavelength conversion by optical-analog-optical conversion, and a management device that manages the all-optical network. The management device is Path management means for managing wavelength resources available for paths in the all-optical network and the usage status of the wavelength resources, Wavelength conversion management means for managing wavelength conversion information of paths including wavelength conversion in the optical node devices constituting the paths, Control means for controlling wavelength conversion in the optical node device based on the managed wavelength resources and usage status, and controlling analog compensation in the optical node device based on the managed wavelength conversion information of the paths. An optical network system comprising.

9. Managing wavelength resources available for paths in an all-optical network including an optical node device that performs wavelength conversion by optical-analog-optical conversion and the usage status of the wavelength resources, Managing wavelength conversion information of paths including wavelength conversion in the optical node devices constituting the paths, Based on the managed wavelength resources and usage status, controlling wavelength conversion in the optical node device, and based on the managed wavelength conversion information of the paths, controlling analog compensation in the optical node device. A control method.

10. Managing wavelength resources available for paths in an all-optical network including an optical node device that performs wavelength conversion by optical-analog-optical conversion and the usage status of the wavelength resources, Managing wavelength conversion information of paths including wavelength conversion in the optical node devices constituting the paths, Based on the managed wavelength resources and usage status, controlling wavelength conversion in the optical node device, and based on the managed wavelength conversion information of the paths, controlling analog compensation in the optical node device. A control program for causing a computer to execute a process.

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