Optical node device and method for controlling the 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

[0003]

[0001] The present invention relates to a management device, an optical node device, an optical network system, a control method, and a non-temporary 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 contract users in Japan in 2020 was about 19 Tbps and has continued to increase at an annual rate of about 57%, and further traffic growth is expected in the future. In contrast, 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 of increasing capacity. Furthermore, with the progress of 5G services in wireless communication, not only the need for increasing capacity but also the need for reducing 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 possible without being restricted by the capacity of electrical switches, but also latency associated with electrical conversion can be eliminated, and low latency can be achieved.

[0003] However, because the same wavelength cannot be used within an optical fiber, paths of the same wavelength arriving at the switching node from different directions cannot be accommodated in the same fiber, resulting in a problem of inefficient path control. To address this, a method is employed in which wavelength converters are used at the switching node to switch wavelengths and accommodate them in the same fiber.

[0004] Furthermore, as technologies related to signal quality in optical networks, for example, Patent Documents 1 and 2 are known. Patent Document 1 discloses PDL (Polarization Dependent Loss) compensation technology, and Patent Document 2 discloses dispersion compensation technology. [Prior art documents] [Patent Documents]

[0005] [Patent Document 1] Japanese Patent Publication No. 2015-186230 [Patent Document 2] Japanese Patent Publication No. 2010-206539 [Overview of the project] [Problems that the invention aims to solve]

[0006] However, existing related technologies do not take into account the wavelength conversion applied in all-photonic networks, making it difficult to effectively suppress signal quality degradation along the path.

[0007] In view of these challenges, this disclosure aims to provide a management device, an optical node device, an optical network system, a control method, and a non-temporary computer-readable medium that can effectively suppress the degradation of signal quality. [Means for solving the problem]

[0008] The management device according to this disclosure comprises: path management means for managing wavelength resources available in a path in an all-optical network equipped with optical node devices that perform wavelength conversion by optical-analog-optical conversion and the usage status of said wavelength resources; wavelength conversion management means for managing wavelength conversion information of the path, including wavelength conversion in the optical node devices that constitute the path; 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 wavelength conversion information of the managed path.

[0009] The optical node device according to this disclosure is an optical node device that constitutes an all-optical network, and comprises: an optical receiving means for receiving an optical signal; a wavelength conversion means for wavelength-converting the received optical signal by optical-analog-optical conversion; an optical transmitting means for transmitting the wavelength-converted optical signal; and a 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.

[0010] The optical network system according to this disclosure comprises an all-optical network equipped with optical node devices that perform wavelength conversion by optical-analog-optical conversion, and a management device for managing the all-optical network, wherein the management device comprises 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 at the optical node devices that constitute the paths, and control means for controlling wavelength conversion at the optical node devices based on the managed wavelength resources and usage status, and for controlling analog compensation at the optical node devices based on the wavelength conversion information of the managed paths.

[0011] The control method relating to this disclosure manages the wavelength resources available in a path and the usage status of said wavelength resources in an all-optical network equipped with optical node devices that perform wavelength conversion by optical-analog-optical conversion, manages the wavelength conversion information of the path including the wavelength conversion in the optical node devices that constitute the path, controls the wavelength conversion in the optical node devices based on the managed wavelength resources and usage status, and controls the analog compensation in the optical node devices based on the wavelength conversion information of the managed path.

[0012] The non-temporary computer-readable medium containing the control program described herein is a non-temporary computer-readable medium containing a control program that causes a computer to execute a process that manages the wavelength resources available for paths in an all-optical network equipped with optical node devices that perform wavelength conversion by optical-analog-optical conversion, the usage status of said wavelength resources, manages wavelength conversion information for paths including wavelength conversion in the optical node devices that constitute said paths, controls the wavelength conversion in the optical node devices based on the managed wavelength resources and usage status, and controls analog compensation in the optical node devices based on the managed wavelength conversion information for said paths. [Effects of the Invention]

[0013] This disclosure provides a management device, an optical node device, an optical network system, a control method, and a non-temporary computer-readable medium that can effectively suppress the degradation of signal quality. [Brief explanation of the drawing]

[0014] [Figure 1] This is a functional block diagram showing the configuration of the wavelength converter in the example under consideration. [Figure 2] This is a functional block diagram showing the configuration of another wavelength converter in the example. [Figure 3] This is a functional block diagram showing specific configuration examples of other wavelength converters considered in the study. [Figure 4]It is a configuration diagram showing the configuration of the all-optical network of the study example. [Figure 5] It is a diagram for explaining problems in the all-optical network of the study example. [Figure 6] It is a functional block diagram showing the schematic configuration of the management device according to the embodiment. [Figure 7] It is a functional block diagram showing the schematic configuration of the node according to the embodiment. [Figure 8] It is a configuration diagram showing a configuration example of the optical network system according to Embodiment 1. [Figure 9] It is a functional block diagram showing a configuration example of each device in the optical network system according to Embodiment 1. [Figure 10] It is a flowchart showing an operation example of the optical network system according to Embodiment 1. [Figure 11] It is a functional block diagram showing a configuration example of each device in the optical network system according to Embodiment 2. [Figure 12] It is a flowchart showing an operation example of the optical network system according to Embodiment 2. [Figure 13] It is a flowchart showing an operation example of the optical network system according to Embodiment 3. [Figure 14] It is a diagram showing the relationship between the NF characteristics and the wavelength according to Embodiment 3. [Figure 15] It is a configuration diagram showing the outline of the hardware of the computer according to the embodiment.

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 an all-photonics network, wavelength conversion is performed as needed by wavelength converters at the nodes. Methods of wavelength conversion that have been proposed or used include all-optical wavelength conversion utilizing the nonlinearity of light and wavelength conversion using transponder functions. All-optical wavelength conversion has the advantage of low delay because the wavelength conversion is performed while the light remains as it is, but it has problems such as high optical loss in the wavelength conversion device and limitations on the transmission distance.

[0017] Figure 1 shows the functional block of a wavelength converter utilizing transponder functionality. As shown in Figure 1, the wavelength converter 900 in the example under consideration includes a receiver 901, a transmitter 902, and a digital signal processing unit 903. The receiver 901 receives an optical signal of the first wavelength (λ1), folds it back in the digital signal processing unit 903, and then transmits an optical signal of the second wavelength (λ2) from the transmitter 902. This converts the wavelength of the optical signal from λ1 to λ2. In the wavelength converter 900, complete wave shaping is achieved through so-called 3R (re-amplification, re-shaping, and re-timing) regeneration via the digital signal processing unit 903, eliminating the transmission distance limitation, but there is a problem of delay occurring in the digital signal processing unit 903.

[0018] Therefore, we consider a configuration that folds back the analog electrical signal between the transmitter and receiver without going through the digital signal processing unit (hereinafter, wavelength conversion using this configuration will be referred to as OAO (optical-analog-optical) wavelength conversion). The functional block of this configuration is shown in Figure 2. As shown in Figure 2, the other wavelength converter 910 in the example under consideration is equipped with a receiver 901 and a transmitter 902, similar to the wavelength converter 900, but the digital signal processing unit 903 is not required. In other words, in the other wavelength converter 910, the analog electrical signal output from the receiver 901 is folded back directly to the transmitter 902 without going through the digital signal processing unit 903.

[0019] In this configuration, since no digital signal processing is performed, it is necessary to add another function to compensate for the signal degradation accumulated in the transmission path up to that point. For example, as shown in Figure 3, one method is to provide an analog signal processing unit 913 between the coherent receiving front end 911 and the coherent transmitting front end 912 to correct the bandwidth.

[0020] In the example shown in Figure 3, the other wavelength converter 910 includes a coherent receiving front end 911, a coherent transmitting front end 912, and an analog signal processing unit 913. The coherent receiving front end 911 is an optical / electrical converter that coherently detects the input optical signal (λ1) based on a reference light source (local oscillator (LO) light) and outputs the analog electrical signal SA1 generated by the detection. The coherent transmitting front end 912 is an electrical / optical converter that coherently modulates the analog electrical signal SA2, obtained by folding the analog electrical signal SA1, based on the transmitting light source and outputs the output optical signal (λ2) generated by the modulation. For example, the wavelength of the output optical signal can be converted from λ1 to λ2 depending on the wavelength of the transmitting 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 signal quality and generates the analog electrical signal SA2. The analog signal processing is analog compensation processing, which compensates for things like bandwidth degradation.

[0021] Furthermore, as shown in Figure 3, in order to control the analog compensation processing, 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 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 amount of bandwidth adjustment in the analog signal processing unit 913 based on the monitoring results.

[0022] Figure 4 shows the all-photonic network using OAO conversion and the node configuration in the example study. In Figure 4, the network configuration is shown as a single, linear transmission path configuration for simplicity. That is, as shown in Figure 4, the all-photonic network 800 in the example study has multiple nodes 810, and each node 810 is connected via an optical transmission path.

[0023] Each node 810 is equipped with optical amplifiers 811 and 812 to compensate for transmission loss, a path switching switch 813, and an OAO wavelength converter pool 814 that has multiple OAO wavelength converters. The path switching switch 813 is connected between optical amplifiers 811 and 812, and the path switching switch 813 switches the path of the path to the OAO wavelength converter pool 814 as needed. After the path requiring wavelength conversion is connected to the OAO wavelength converter pool 814, the wavelength is converted, for example, from λ1 to λ2, and sent out to the optical transmission path.

[0024] However, while existing networks are designed to guarantee reach within the network range (e.g., within 10 hops) regardless of which path is assigned to which wavelength, installing OAO wavelength conversion within the network presents a challenge in that signal quality changes depending on the location of the wavelength conversion (where it is installed between the transmitting and receiving nodes), making it difficult to guarantee reach. For example, as shown in Figure 5, when OAO wavelength conversion is performed at node 810A, it is close to the transmitting end 820 and the signal degradation is not advanced, so the effect of analog compensation is weak, and because the remaining transmission path is long, there is a possibility that the signal will fall below the minimum receiving sensitivity along the way. Also, when wavelength conversion is performed at node 810E, which is close to the receiving end 830, reach to node 810E is guaranteed, but applying analog compensation to a degraded signal with a poor S / N ratio may actually exacerbate the S / N degradation and cause the signal to fall below the minimum receiving sensitivity.

[0025] Furthermore, the network contains devices with wavelength characteristics, such as optical amplifiers. For example, the Noise Figure (NF) has poor characteristics at shorter wavelengths. Therefore, the characteristics may change depending on the wavelength before and after wavelength conversion. For example, when converting from one short wavelength to another, the characteristics may be worse compared to converting from one long wavelength to another.

[0026] As described above, numerous analog compensation technologies have been disclosed, including analog PDL compensation technology in Patent Document 1 and analog dispersion compensation technology in Patent Document 2. However, these conventional analog compensation technologies were not designed on the premise that OAO wavelength conversion would be implemented, and it is necessary to separately consider network control that takes into account the location of the above-mentioned wavelength conversion. Therefore, the embodiment described herein is made in view of the above-mentioned problems.

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

[0028] (Summary of the embodiment) Figure 6 shows the schematic configuration of the management device according to the embodiment, and Figure 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 OAO conversion (optical-analog-optical conversion) and constitutes an all-photonic network. Management device 10 manages and controls the all-photonic network, including Node 20. For example, management device 10 is a Network Management System (NMS) that manages the network.

[0030] As shown in Figure 6, the management device 10 comprises 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 use in paths within the all-photonics network and the usage status of those wavelength resources. The path management unit 11 is, for example, a path database that manages and maintains wavelength resource (information) and usage status (information).

[0031] The wavelength conversion management unit 12 manages wavelength conversion information for the path, including wavelength conversion at the nodes 20 that constitute the path. The wavelength conversion management unit 12 is, for example, a wavelength conversion management database that manages and stores the wavelength conversion information for the path.

[0032] The control unit 13 controls wavelength conversion at node 20 based on the wavelength resources and usage status managed by the path management unit 11, and controls analog compensation at node 20 based on the wavelength conversion information of the path managed by the wavelength conversion management unit 12. For example, the control unit 13 may notify node 20 of the wavelength conversion information of the path, thereby controlling node 20 to perform analog compensation for all paths that have undergone wavelength conversion in the path prior to 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, and analog compensation node identification information, may be further managed. In this case, the control unit 13 may determine candidate paths for analog compensation based on the wavelength conversion characteristic information and control the node 20 to perform analog compensation on the determined paths. In addition, the control unit 13 may divide the entire wavelength band into multiple parts and control the wavelength conversion to perform it so that the NF (Noise Figure) characteristics are averaged.

[0034] As shown in Figure 7, node 20 comprises an optical receiving unit 21, a wavelength conversion unit 22, an optical transmitting unit 23, and a node control unit 24. The optical receiving unit 21 receives an optical signal from the optical transmission path. The wavelength conversion unit 22 converts the wavelength of the optical signal received by the optical receiving unit 21 using OAO wavelength conversion. The optical transmitting unit 23 transmits the wavelength-converted optical signal from 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 notifications from the management device 10. For example, the node control unit 24 may monitor all paths that have undergone wavelength conversion in the path prior to its own node 20 in response to wavelength conversion information of the path notified by the management device 10, and control the node control unit 24 to perform analog compensation based on the monitoring results. Alternatively, the node control unit 24 may control the node control unit 24 to perform analog compensation on the relevant path based on information of the path to be analog-compensated notified by the management device 10.

[0036] This configuration effectively suppresses signal quality degradation along the path in an all-photonics network using OAO wavelength conversion. Specifically, as a first effect, the nodes in the wavelength-converted path perform appropriate analog compensation, thereby guaranteeing path arrival. As a second effect, by performing wavelength conversion in a way that averages the NF characteristics, it becomes possible to ensure uniform path arrival.

[0037] (Embodiment 1) Next, Embodiment 1 will be described. In this embodiment, an example will be described in which a node monitors all paths that have undergone wavelength conversion in the path prior to the node and performs analog compensation.

[0038] <System Configuration> First, the configuration of this embodiment will be described using Figures 8 and 9. Figure 8 shows an example of the configuration of an optical network system according to this embodiment. As shown in Figure 8, the optical network system 1 according to this embodiment includes an NMS 100 and a plurality of nodes 200. The plurality of nodes 200 are connected to each other via an optical transmission path 300 so as to be able to communicate optically. The plurality of nodes 200 and the NMS 100 are also connected, for example, via the optical transmission path 300, but they may be connected to each other so as to be able to communicate via any other transmission path.

[0039] The multiple nodes 200 are optical communication devices that perform OAO wavelength conversion. In other words, the multiple nodes 200 constitute an all-photonics network 2 using OAO wavelength conversion. In the example in Figure 8, the multiple nodes 200 constitute a mesh-shaped network, but other network configurations such as a ring shape may also be configured. Furthermore, the multiple nodes 200 constitute a path from a transmitting node (transmitting end) to a receiving node (receiving end) in response to control from the NMS 100, and transmit data (optical signals) along the path.

[0040] The NMS100 is a management device that manages and controls an all-photonics network 2, which includes multiple nodes 200. The NMS100 manages and controls the paths formed by the nodes 200 in the all-photonics network 2. The NMS100 manages the paths and wavelengths from the transmitting node to the receiving node, and sets the paths and wavelengths for the nodes 200 along the paths.

[0041] Figure 9 shows an example of the configuration of each device in the optical network system according to this embodiment. As shown in Figure 9, the NMS 100 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 paths made up of multiple nodes 200 of the all-photonics network 2, and manages and maintains the wavelength resources available for the path (wavelength resource information) and the usage status of those wavelength resources (usage status information). The path database 101 maintains the wavelength resources and usage status at each node 200 that constitutes the path. Wavelength resources (wavelength resource information) indicate all wavelengths available for the path, and usage status (usage status information) indicates the wavelengths being used in the path.

[0043] The wavelength conversion management database 102 manages and maintains the wavelength conversions performed by the nodes 200 that constitute the path. The wavelength conversion management database 102 maintains wavelength conversion information for each node 200 that constitutes the path. The wavelength conversion information is information that can identify the wavelength conversion at each node 200 along the path, and may, for example, indicate whether or not a wavelength conversion occurred at each node 200, or indicate the wavelengths before and after conversion at each node.

[0044] The network control unit 103 controls paths and the nodes 200 that constitute them by referring to the path database 101 and the wavelength conversion management database 102. Based on the wavelength resources and usage status in the path database 101, the network control unit 103 performs wavelength conversion on paths that require it. That is, the network control unit 103 instructs each node 200 on a path to perform wavelength conversion as needed and stores wavelength conversion information showing the results of the wavelength conversion in the wavelength conversion management database 102. The network control unit 103 also notifies all nodes 200 of the wavelength conversion information for all paths in the wavelength conversion management database 102.

[0045] Furthermore, node 200 includes a transmission loss-compensating optical amplifier 201 (201a and 201b), an optical switch (SW) 202, a node loss-compensating 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-compensating optical amplifier 201 is an optical amplifier that compensates for transmission loss occurring in the optical fiber by amplifying the optical signal. The transmission loss-compensating optical amplifier 201a is a receiving amplifier that receives the optical signal. The transmission loss-compensating optical amplifier 201a receives optical signals on a fiber-by-fiber basis from adjacent nodes on the transmitting node side via the input optical fiber 300a and compensates for the transmission loss of the input optical fiber 300a on a fiber-by-fiber basis. The transmission loss-compensating optical amplifier 201a outputs the optical signal after transmission loss compensation to the optical switch 202.

[0047] The transmission loss-compensated optical amplifier 201b is a transmitting amplifier that transmits optical signals. The transmission loss-compensated optical amplifier 201b compensates for the transmission loss of the optical signal from the optical switch 202 on a fiber-by-fiber basis. The transmission loss-compensated optical amplifier 201b outputs the optical signal on a fiber-by-fiber basis, after 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 on a wavelength basis. The optical switch 202 is connected between the receiving-side transmission loss compensation optical amplifier 201a and the transmitting-side transmission loss compensation optical amplifier 201b. The optical switch 202 switches the add / drop of a predetermined optical signal (path) according to control from the node controller 207. The optical switch 202 switches on a wavelength basis for the optical signal on a fiber-by-fiber basis from the transmission loss compensation optical amplifier 201a and outputs the optical signal of the wavelength to be dropped to the node loss compensation optical amplifier 203a via the wavelength conversion port. The optical switch 202 also receives an optical signal from the node loss compensation optical amplifier 203b via the analog wavelength converter pool 210 and the wavelength to be added to the received fiber-by-fiber optical signal and outputs the optical signal of the wavelength to be added to the transmission loss compensation optical amplifier 201b.

[0049] The node loss compensation optical amplifier 203 is an optical amplifier that compensates for losses occurring at the node by amplifying the optical signal. The receiving side (drop side) node loss compensation optical amplifier 203a compensates for the loss of optical signals on a per-fiber basis from the wavelength conversion port of the optical switch 202 and outputs the loss-compensated optical signal to the wavelength switch 204a. The transmitting side (add side) node loss compensation optical amplifier 203b compensates for the loss of optical signals on a per-fiber basis 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 on a wavelength basis. The receiving wavelength switch 204a separates the optical signal from the node loss-compensated optical amplifier 203a on a fiber-by-fiber basis and outputs the separated optical signal to the OAO wavelength converter 211 of the analog wavelength converter pool 210. The transmitting wavelength switch 204b bundles the optical signals from the OAO wavelength converter 211 of the analog wavelength converter pool 210 on a fiber-by-fiber basis and outputs the optical signal on a fiber-by-fiber basis to the node loss-compensated optical amplifier 203b.

[0051] The tap coupler 205 taps part or all of the wavelength-based optical signal output from the receiving wavelength switch 204a. The optical path monitor 206 monitors the quality of the optical signal tapped by the tap coupler 205. In response to 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 multiple OAO wavelength converters 211. Multiple OAO wavelength converters 211 are provided, corresponding to the wavelength of the input optical signal and the wavelength of the output optical signal. The OAO wavelength converter 211 is a wavelength converter capable of performing OAO wavelength conversion and analog compensation. The OAO wavelength converter 211 includes, for example, a coherent receiving front end, a coherent transmitting front end, and an analog signal processing unit (analog compensator) as shown in Figure 3, but other configurations are also acceptable as long as OAO wavelength conversion is possible. In response to control from the node controller 207, the OAO wavelength converter 211 performs analog compensation, or wavelength conversion and analog compensation, on the wavelength-unit optical signal from the wavelength switch 204a, and outputs the wavelength-converted or analog-compensated optical signal to the wavelength switch 204b.

[0053] For example, an analog compensator that performs bandwidth compensation, PDL compensation, dispersion compensation, etc., is installed in the OAO wavelength converter 211. The optical path monitor 206 varies depending on the configuration of the analog compensator; for example, a spectrum analyzer is used when performing bandwidth 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 node 200. The node controller 207 controls the operation of each device in response to control from NMS 100. When the node controller 207 receives a wavelength conversion instruction from NMS 100, it controls the optical switch 202 to switch to the corresponding wavelength and controls the OAO wavelength converter 211 to convert the wavelength. Furthermore, when the node controller 207 receives wavelength conversion information for all paths from NMS 100, it determines the path (wavelength) to monitor and controls the analog compensation of the corresponding OAO wavelength converter 211 based on the results monitored by the tap coupler 205 and the optical path monitor 206.

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

[0056] As shown in Figure 10, first, the NMS 100 performs wavelength conversion of the path (S101). When a path request is issued, the NMS 100 refers to the path database 101, determines the path that requires wavelength conversion based on wavelength resources and usage, and notifies the node 200 that will perform the wavelength conversion of the determined path. For example, it notifies information that identifies the path, the wavelength before conversion, the wavelength after conversion, etc. The node controller 207 of each node 200 controls the optical switch 202 and the OAO wavelength converter 211 to convert the wavelength of the corresponding path based on the information received from the NMS 100. Furthermore, once each node 200 has performed wavelength conversion, the NMS 100 stores the wavelength conversion information of the path, indicating that each node 200 has performed wavelength conversion in the path, in the wavelength conversion management database 102.

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

[0058] Next, each node 200 sets the path drop settings (S103). When each node 200 receives wavelength conversion information for all paths from the NMS 100, the node controller 207 determines which paths (wavelengths) to drop based on the wavelength conversion information for all paths. The paths to drop are the paths to be monitored (analog compensation candidates). Specifically, from the wavelength conversion information of the paths, the node controller 207 extracts the paths in the path before its own node that have undergone wavelength conversion by other nodes 200, and sets the optical switch 202 to drop all the extracted paths (wavelengths).

[0059] Next, each node 200 connects the wavelength switch 204a to the OAO wavelength converter 211 (S104). At each node 200, the node controller 207 configures the wavelength switch 204a so that the drop-configured path (wavelength), i.e., all paths that have undergone wavelength conversion in the path prior to the node, are connected to the demultiplexed OAO wavelength converter 211.

[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 drop-configured path (wavelength), that is, all paths that have undergone wavelength conversion in the path prior to the node.

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

[0062] Next, each node 200 performs the path add setting (S107) and completes the operation (setting) (S108). At each node 200, once analog compensation is performed according to the monitoring results, the node controller 207 sets the optical switch 202 and the wavelength switch 204b so that the dropped path (wavelength), i.e., the path for which analog compensation has been performed according to the monitoring results, is added to the original fiber. The same operation is performed at the next node 200.

[0063] As described above, in this embodiment, in an all-photonics network using OAO wavelength conversion, the NMS refers to a path database that manages wavelength resources and usage status in the NMS, notifies the node of information on paths requiring wavelength conversion and performs wavelength conversion, and also stores the 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 for all wavelength-converted paths. Each node drops all wavelength-converted paths in the path prior to its own node and monitors the signal quality. Based on the monitoring information, each node performs analog compensation (or wavelength conversion and analog compensation) in the OAO wavelength converter for paths that exceed a predetermined degradation threshold. In this way, by monitoring the signal quality of wavelength-converted paths and performing analog compensation according to the degradation status, it is possible to guarantee the arrival of the path.

[0064] (Embodiment 2) Next, Embodiment 2 will be described. In this embodiment, an example will be described in which the NMS determines the path for analog compensation.

[0065] <System Configuration> First, the configuration of this embodiment will be explained using Figure 11. Figure 11 shows an example of the configuration of each device in the optical network system according to this embodiment. Here, only the differences from the configuration in Embodiment 1 will be explained, and the explanation of identical configurations will be omitted.

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

[0067] Furthermore, in addition to the configuration of Embodiment 1, the NMS100 includes a wavelength conversion characteristics database 104 (DB). The wavelength conversion characteristics database 104 holds wavelength conversion characteristics information that indicates the wavelength conversion characteristics of a path. The wavelength conversion characteristics information includes the transmission distance before wavelength conversion (A), the transmission distance after wavelength conversion (B), the estimated signal degradation (C), and the analog compensation (bandwidth recompensation) node number (D). Preferably, the wavelength conversion characteristics information includes all of the transmission distance before wavelength conversion (A), the transmission distance after wavelength conversion (B), the estimated signal degradation (C), and the analog compensation node number (D), but it may include at least one of the pieces of information. For example, it may include the estimated signal degradation (C) and the analog compensation node number (D).

[0068] The transmission distance before wavelength conversion (A) is the transmission distance (e.g., number of hops) from the transmitting end to the node where wavelength conversion is performed in the path. The transmission distance after wavelength conversion (B) is the transmission distance from the node where wavelength conversion is performed to the receiving end in the path. The estimated signal degradation (C) is the estimated degradation of the optical signal in the path. The degradation is the degree of degradation of the optical signal received at the receiving end relative to the optical signal transmitted from the transmitting end. For example, the degradation can be estimated from the transmission distance before wavelength conversion (A) and the transmission distance after wavelength conversion (B). 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. Furthermore, the wavelength conversion characteristic information is map information that maps each piece of information. Specifically, the network map shows the connection relationships of each node in the network, illustrating the path of each node. For each path, the transmission distance before wavelength conversion (A), the transmission distance after wavelength conversion (B), the estimated signal degradation (C), and the analog compensation node number (D) are shown.

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

[0070] As shown in Figure 12, first, the NMS 100 performs wavelength conversion of the path (S201). Similar to Embodiment 1, when a path request is issued, the NMS 100 refers to the path database 101 which manages wavelength resources and usage status, notifies the node 200 of the information of the path that requires wavelength conversion and performs the wavelength conversion, and also stores the wavelength conversion information of the path in the wavelength conversion management database 102.

[0071] Next, the NMS100 creates a wavelength conversion characteristics database 104 (S202). By creating the wavelength conversion characteristics database 104, the NMS100 selects paths that are presumed to have already undergone degradation. Specifically, it generates map information (wavelength conversion characteristics information) that maps the transmission distance before wavelength conversion (A), the transmission distance after wavelength conversion (B), the estimated signal degradation level (C), and the analog compensation node number (D), and stores this map information in the wavelength conversion characteristics database 104. For example, for each path, the transmission distance before wavelength conversion (A) and the transmission distance after wavelength conversion (B) are determined from the path's wavelength conversion information (path and wavelength conversion node), and the estimated signal degradation level (C) is determined from the transmission distance before wavelength conversion (A) and the transmission distance after wavelength conversion (B). From the nodes on the path where analog compensation is possible, a node for analog compensation is selected, and the analog compensation node number (D) is identified. The NMS100 refers to the wavelength conversion characteristics database 104 and determines candidate paths for analog compensation according to the map information. For example, the path to be analog-compensated is determined based on the estimated signal degradation level (C) of the path. To give a specific example, if the number of hops to guarantee reachability is 10, and there are two paths, Path 1 (A=1, B=9, C=5, D=8) and Path 2 (A=7, B=3, C=6, D=9), then if C=5 or higher is selected for analog compensation, then Path 1 and Path 2 will be selected for analog compensation.

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

[0073] Next, the notified node 200 performs a path drop setting (S204). When node 200 receives information about the path to be analog compensated from NMS 100, the node controller 207 sets the optical switch 202 to drop the notified path (wavelength) to be analog compensated.

[0074] Next, node 200 connects the wavelength switch 204a to the OAO wavelength converter 211 (S205). At node 200, node controller 207 configures the wavelength switch 204a so that the path to be analog compensated, which has been set to drop, is connected to the demultiplexed OAO wavelength converter 211.

[0075] Next, node 200 performs analog compensation on the relevant path (S206). At node 200, analog compensation (or wavelength conversion and analog compensation) is performed on the relevant path connected to the OAO wavelength converter 211 by the OAO wavelength converter 211.

[0076] Next, node 200 performs the path add setting (S207) and completes the operation (setting) (S208). When analog compensation is performed on the path to be compensated at node 200, node controller 207 sets the optical switch 202 and wavelength switch 204b so that the dropped path (wavelength) is added to the original fiber. This operation is performed only by node 200 that has received notification from NMS 100.

[0077] As described above, in this embodiment, as an alternative method for performing analog compensation in an all-photonics network using OAO wavelength conversion, a wavelength conversion characteristics database is created and maintained, which maps the transmission distance before wavelength conversion, the transmission distance after wavelength conversion, the estimated signal degradation level, and the analog compensation node number. Candidate paths for analog compensation are determined according to the map, and analog compensation is performed only on those paths. In this way, by pre-calculating the signal quality of the wavelength-converted paths and performing analog compensation according to the degradation level, it becomes possible to guarantee the arrival of the path.

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

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

[0080] As shown in Figure 13, NMS100 first performs wavelength conversion of the path considering the wavelength characteristics (S301). When a path request is issued, NMS100 refers to the path database 101 which manages wavelength resources and usage status, notifies the node 200 of the information of the path that requires wavelength conversion and performs the wavelength conversion, and also stores the wavelength conversion information of the path in the wavelength conversion management database 102.

[0081] At this time, the NMS100 performs wavelength conversion considering the wavelength characteristics of the devices in the network. For example, wavelength characteristics include the NF characteristics of the optical amplifier installed in node 200. The NF characteristics of the optical amplifier are characterized in that the characteristics are inferior on the shorter wavelength side compared to the longer wavelength side. Figure 14 is a conceptual diagram showing the NF characteristics and the wavelength assignment algorithm. For example, the entire wavelength band is divided into 10 parts, and wavelength conversion is performed based on the wavelength band so that the NF characteristics are averaged. In one example, at node 200, the NF characteristics can be averaged by controlling the conversion of wavelength band 1 to wavelength band 10, wavelength band 4 to wavelength band 5, etc. That is, wavelengths are converted between wavelength bands where the amount of decrease (degradation) relative to the average value and the amount of increase (improvement) relative to the average value are equal (the absolute values ​​are equal). Note that the operation from S102 onwards is the same as in Embodiment 1, so the explanation is omitted.

[0082] As described above, in this embodiment, wavelength conversion may be performed considering the wavelength characteristics of devices in the network. For example, the entire wavelength band may be divided into multiple bands, and wavelength conversion may be performed so that the NF characteristics are averaged. By performing wavelength conversion while considering characteristics such as NF in this way, the quality of the path can be made uniform, and the number of paths requiring analog compensation can be reduced.

[0083] This disclosure is not limited to the embodiments described above, and may be modified as appropriate without departing from its spirit.

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

[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 of the functions described in the embodiments. The programs may be stored on non-temporary computer-readable media or tangible storage media. Examples, but not limited to, include random-access memory (RAM), read-only memory (ROM), flash memory, solid-state drives (SSDs), or other memory technologies, CD-ROMs, digital versatile discs (DVDs), Blu-ray® discs, or other optical disc storage, magnetic cassettes, magnetic tapes, magnetic disk storage, or other magnetic storage devices. The programs may be transmitted over temporary computer-readable media or communication media. Examples, but not limited to, include electrical, optical, acoustic, or other forms of propagating signals.

[0086] Although the present disclosure has been described above with reference to embodiments, the present disclosure is not limited to the embodiments described above. Various modifications to the structure and details of the present disclosure can be understood by those skilled in the art within the scope of the present disclosure.

[0087] Some or all of the above embodiments may also be described as follows, but are not limited to the following: (Note 1) A path management means for managing wavelength resources available for paths in an all-optical network equipped with an optical node device that performs wavelength conversion by optical-analog-optical conversion, and the usage status of said wavelength resources. Wavelength conversion management means for managing wavelength conversion information of a path, including wavelength conversion in the optical node device that constitutes the path, A control means 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 wavelength conversion information of the managed path. A control device equipped with the following features. (Note 2) The control means notifies the optical node device of the wavelength conversion information of the path, thereby controlling the optical node device in the path to perform analog compensation for all paths that have undergone wavelength conversion in the path prior to the optical node device. The control device described in Appendix 1. (Note 3) The system includes a wavelength conversion characteristic management means for managing wavelength conversion characteristic information that indicates the wavelength conversion characteristics of the aforementioned path, The control means determines candidate paths for analog compensation based on the wavelength conversion characteristic information, and controls the optical node device to perform analog compensation on the determined paths. The control device described in Appendix 1. (Note 4) The wavelength conversion characteristic information includes the transmission distance in the path before wavelength conversion, the transmission distance in the path after wavelength conversion, the estimated signal degradation degree of the path, and identification information of the node performing analog compensation in the path. The control device described in Appendix 3. (Note 5) The control means divides the entire wavelength band into multiple bands and controls the wavelength conversion so that the NF (Noise Figure) characteristics are averaged. A control device as described in any one of the items 1 to 4 of the appendix. (Note 6) An optical node device that constitutes an all-optical network, An optical receiving means for receiving an optical signal, Wavelength conversion means for converting the wavelength of the received optical signal by optical-analog-optical conversion, A light transmitting means for transmitting the wavelength-converted optical signal, A node control means that controls 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 equipped with the following features. (Note 7) The system includes a monitoring means for monitoring the optical signal input to the wavelength conversion means, The node control means monitors all paths that include its own device and have undergone wavelength conversion in the path prior to its own device, based on the wavelength conversion information of the path notified by the management device, using the monitoring means, and controls the monitoring means to perform analog compensation based on the monitoring results. The optical node device described in Appendix 6. (Note 8) The node control means controls the monitored paths to perform analog compensation on paths whose quality has deteriorated below a predetermined threshold. The optical node device described in Appendix 7. (Note 9) The node control means controls the operation to perform analog compensation on the corresponding path based on the information of the path to be compensated for analogally, which is notified by the management device. The optical node device described in Appendix 6. (Note 10) The system comprises an all-optical network equipped with optical node devices that perform wavelength conversion by optical-analog-optical conversion, and a management device that manages the all-optical network. The aforementioned control device is A path management means for managing wavelength resources available for paths in the aforementioned all-optical network and the usage status of said wavelength resources, Wavelength conversion management means for managing wavelength conversion information of a path, including wavelength conversion in the optical node device that constitutes the path, A control means 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 wavelength conversion information of the managed path. An optical network system equipped with [the following features]. (Note 11) In an all-optical network equipped with optical node devices that perform wavelength conversion by optical-analog-optical conversion, the system manages the wavelength resources available for the paths and the usage status of said wavelength resources. The wavelength conversion information of the path, including the wavelength conversion in the optical node device that constitutes the path, is managed. Based on the managed wavelength resources and usage status, the wavelength conversion in the optical node device is controlled, and based on the wavelength conversion information of the managed path, analog compensation in the optical node device is controlled. Control method. (Note 12) In an all-optical network equipped with optical node devices that perform wavelength conversion by optical-analog-optical conversion, the system manages the wavelength resources available for the paths and the usage status of said wavelength resources. The wavelength conversion information of the path, including the wavelength conversion in the optical node device that constitutes the path, is managed. Based on the managed wavelength resources and usage status, the wavelength conversion in the optical node device is controlled, and based on the wavelength conversion information of the managed path, analog compensation in the optical node device is controlled. A non-temporary, computer-readable medium containing control programs for executing processes on a computer. (Note 13) A control method in an all-photonics network using analog wavelength conversion, which involves directly connecting the analog signal output of an optical receiver to the analog signal input of an optical transmitter to perform wavelength conversion, NMS is a path database that manages wavelength resources and usage, It is equipped with a wavelength management database for managing wavelength conversion information, A path control method characterized by performing wavelength conversion based on the aforementioned path database and performing analog compensation by referring to the aforementioned wavelength conversion management database. (Note 14) The path control method according to Appendix 13, characterized in that at a node on the communication path, it refers to the wavelength conversion management-based information, monitors all paths that have undergone wavelength conversion in the path prior to the node, and performs analog compensation based on the monitored information. (Note 15) The NMS comprises a wavelength conversion characteristics database that stores the transmission distance before wavelength conversion, the transmission distance after wavelength conversion, the estimated signal degradation degree, and the analog compensation node number, and determines candidate paths for analog compensation by referring to the wavelength conversion characteristics database, and performs analog compensation only on the paths described in Appendix 13, characterized in that the path control method described in Appendix 13 is characterized in that the NMS has a wavelength conversion characteristics database that stores the transmission distance before wavelength conversion, the transmission distance after wavelength conversion, the estimated signal degradation degree, and the analog compensation node number, and determines candidate paths for analog compensation by referring to the wavelength conversion characteristics database, and performs analog compensation only on the paths described. (Note 16) The path control method according to any one of appendices 13 to 14, characterized in that the entire wavelength band is divided into multiple parts and the wavelength conversion is performed so that the NF characteristics are averaged. (Note 17) A network management system characterized by comprising the path control method described in Appendix 13. (Note 18) An optical network device characterized by comprising the path control method described in Appendix 13. (Note 19) An optical network control program characterized by comprising the path control method described in Appendix 13. [Explanation of Symbols]

[0088] 1. Optical Network System 2. All-Photonics Network 10 Management device 11. Path Management Department 12 Wavelength Conversion Management Unit 13 Control Unit 20 nodes 21 Optical receiving section 22 Wavelength conversion section 23 Optical Transmitter 24 Node Control Unit 30 Computers 31 processors 32 memory 100 NMS 101 Path Database 102 Wavelength Conversion Management Database 103 Network Control Unit 104 Wavelength Conversion Characteristics Database 200 nodes 201 Transmission Loss Compensation Optical Amplifier 202 Optical switch 203 Node Loss Compensated Optical Amplifier 204 wavelength switch 205 Tap Coupler 206 Optical Path Monitor 207 Node Controller 210 Analog Wavelength Converter Pool 211 OAO Wavelength Converter 300 Optical Transmission Paths 300a, 300b optical fiber

Claims

1. An optical receiving unit that receives optical signals in an APN (All Photonics Network), A wavelength conversion unit that converts the wavelength of the received optical signal using the OAO (Optical Analog Optical) method, A control unit that receives a notification from the Network Management System (NMS) that manages the APN and instructs the wavelength conversion unit to perform the wavelength conversion, An optical transmission unit that transmits the wavelength-converted optical signal, Includes, The control unit instructs the wavelength conversion unit to perform analog compensation in response to the notification. Optical node device.

2. The wavelength conversion unit includes a coherent receiving front end, a coherent transmitting front end, and an analog signal processing unit that performs analog compensation. The optical node device according to claim 1.

3. The analog compensation includes at least one of bandwidth compensation, PDL (Polarization Dependent Loss) compensation, and dispersion compensation. The optical node device according to claim 1 or claim 2.

4. The notification includes at least one of the following: information identifying the path in the APN, the wavelength before conversion, and the wavelength after conversion. The optical node device according to any one of claims 1 to 3.

5. The control unit instructs the adjustment of the analog compensation amount according to the amount of degradation of the path quality in the APN. The optical node device according to any one of claims 1 to 4.

6. The unit comprises a monitor unit that monitors the optical signal input to the wavelength conversion unit, The control unit instructs wavelength-based analog compensation based on the monitored results. The optical node device according to any one of claims 1 to 5.

7. The monitored result includes the signal quality of the wavelength-converted path in the path prior to the device itself. The optical node device according to claim 6.

8. Includes an optical wavelength selector switch which is an optical switch capable of switching the path of an optical signal on a wavelength basis, The control unit instructs the optical wavelength selector switch to perform a predetermined optical signal branching and insertion (add / drop). The optical node device according to any one of claims 1 to 7.

9. The notification includes information relating to the Noise Figure (NF) characteristics in the APN, The wavelength conversion unit performs wavelength conversion according to the NF characteristics. The optical node device according to any one of claims 1 to 8.

10. Receiving an optical signal in an APN (All Photonics Network), The system receives a notification from the Network Management System (NMS) that manages the aforementioned APN, and converts the wavelength of the received optical signal using the Optical Analog Optical (OAO) method. In response to the aforementioned notification, analog compensation will be performed. The wavelength-converted optical signal is transmitted. A method for controlling an optical node device.

Images