JP2016025623A - Node optical switch device and optical switch method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To solve the problem that a loss of an optical node device increases in an optical node device compatible with CDC (Colorless, Directionless, Contentionless) functions.SOLUTION: A node optical switch device used for an optical node device for terminating an optical path includes: a node optical switch for receiving a wavelength multiplex optical signal; and a control unit for controlling the node optical switch. The node optical switch branches the wavelength multiplex optical signal with a predetermined branch ratio, selects a desired wavelength signal from each branched wavelength multiplex optical signal, and outputs it. The control unit sets a branch ratio in accordance with an attribute of the optical path.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a node optical switch device and an optical switch method, and more particularly to a node optical switch device and an optical switch method used in an optical node device.

  In recent years, traffic flowing through a network continues to grow rapidly due to the rapid spread of mobile terminals represented by smartphones and large-capacity data communication such as high-definition images due to advancement of mobile terminals. Specifically, for example, the total download traffic of broadband subscribers in Japan in FY 2012 is about 1.7 terabits per second (Tbps), and it continues to increase at an annual rate of about 20%. There is a report. Furthermore, there is a prediction that it will be about petabit per second (Pbps) in 2020.

  In such a situation, a core network that supports large-capacity communication has a large capacity such as wavelength division multiplexing (WDM) technology that multiplexes and transmits optical signals of different wavelengths on one optical fiber. Technology development has been underway. In early WDM communication, nodes are connected point-to-point, converted into electrical signals within the nodes, then converted back to optical signals and transmitted to the next node. It was adopted. However, since the traffic passing through the node is also once converted into an electric signal, the number of electric switch ports and the increase in power have become remarkable in a network whose capacity is increasing. For this reason, in recent years, technologies such as an optical add-drop (OADM) system and an optical cross-connect (OXC) system, in which traffic passing through a node is cut through as an optical signal, have been developed. Has been developed.

  Along with the above-mentioned expansion of the transmission capacity in units of fibers, expansion of the transmission area is also underway. That is, the complexity of networks is increasing, such as a conventional ring network in which each node is arranged in a ring shape, a multi-ring network in which a plurality of rings are connected, and a mesh network in which nodes are arranged in a mesh shape. At the same time, the complexity of the optical layer to cut through is also increasing.

  On the other hand, the popularization of mobile terminals and the stream distribution of image data cause sudden traffic fluctuations. Therefore, the network is required to flexibly cope with traffic fluctuations with the increase in capacity described above. In order to respond to such new demands, research and development of an elastic network and the like corresponding to dynamic traffic fluctuations have been promoted in recent years. The elastic network has flexible wavelength allocation that has been fixed in a grid standardized by the International Telecommunication Union (ITU) Telecommunications Standardization Sector (ITU-T), and has an efficient wavelength. Allocation is going to be done. In such a complicated network in the optical layer, the importance of network control technology for dynamically and flexibly controlling the network is increasing.

  An example of a node configuration that accommodates optical paths dynamically and flexibly in such a complicated network is described in Patent Document 1.

  FIG. 16 shows a related node configuration described in Patent Document 1. The related node configuration includes K input-side optical fiber transmission lines 2-1 to 2-K, an optical cross-connect unit 3, and K output-side optical fiber transmission lines 4-1 to 4-K. . J wavelength division multiplexed optical signals 1-1 to 1-J are input to the input side optical fiber transmission lines 2-1 to 2-K, respectively, and are output from the output side optical fiber transmission lines 4-1 to 4-K. J wavelength division multiplexed optical signals 5-1 to 5-J are output, respectively. Further, in order to realize the add / drop function, a drop-side optical signal terminator 30 and an add-side optical signal terminator 31 are provided.

  Between the input side optical fiber transmission lines 2-1 to 2-K and the optical cross-connect unit 3, the wavelength division multiplexed optical signals from the K input side optical fiber transmission lines 2-1 to 2-K are transmitted. Branching optical couplers 21-1 to 21 -K are provided. The optical output levels of the wavelength division multiplexed optical signals from the input optical fiber transmission lines branched by the K optical couplers 21-1 to 21-K are adjusted by the optical amplifiers 31-1 to 31-K, respectively. The Thereafter, the 1 × L optical couplers (star couplers) 32-1 to 32-K are branched into L wavelength division multiplexed optical signals corresponding to the number of receivers 35-1 to 35-L.

  Thereby, the wavelength multiplexed signal from each input side optical fiber transmission line is connected to each of the fiber selection switches 33-1 to 33-L. The fiber selection switch selects the wavelength division multiplexed optical signal of any one of the K input-side optical fiber transmission lines. The fiber selection switch can be constituted by a switch of K input and 1 output. Wavelength division optical signals from all K input side optical fiber transmission lines are given to the fiber selection switch 33-1, for example, wavelength division multiplexed optical signals 1-1, 36, of the input side optical fiber transmission line 2-1. Only 37 is selected by the fiber selection switch 33-1. The selected wavelength division multiplexed optical signal 38-1 is given to an optical variable filter (tunable filter) 34-1 and only an optical signal 39-1 having a desired wavelength is selected. The optical variable filter selects only a desired wavelength from a wavelength division multiplexed optical signal including a plurality of wavelengths.

  FIG. 17 shows a configuration of an A input 1 output (A × 1) switch constituting the fiber selection switches 33-1 to 33-L. An A × 1 switch having one A input and one output has the ability to extract one signal from A input signals, and can be configured by combining the basic element 1 × 2 switch 40.

  By adopting such a configuration, according to the related node configuration, wavelength-independent (colorless), route-independent (directionless: Directionless), and collision avoidance (contentionless: Contentionless) 3 It is said that the characteristic (CDC) can be realized.

JP 2014-010437 A (paragraphs [0007] to [0020], FIGS. 3 and 4)

  The optical signal termination device 30 used in the related node configuration described above includes an optical coupler, a fiber selection switch, and an optical variable filter. Then, the optical coupler branches into the number of wavelength division multiplexed optical signals corresponding to the number of receivers, and the fiber selection switch selects the wavelength division multiplexed optical signal of any one fiber. For this reason, a wavelength division multiplexed optical signal from another fiber other than the wavelength division multiplexed optical signal including the desired optical signal to be taken out (dropped) in the related node configuration is not used, and loss due to branching occurs.

  As described above, the optical node device corresponding to the CDC (Colorless, Directionless, Contentionless) function has a problem that the loss of the optical node device increases.

  An object of the present invention is to provide a node optical switch device and an optical switch method that solve the problem that the loss of the optical node device increases in the optical node device corresponding to the CDC function, which is the above-described problem. is there.

  The node optical switch device of the present invention is a node optical switch device used for an optical node device that terminates an optical path, and includes a node optical switch that receives a wavelength-multiplexed optical signal and a control unit that controls the node optical switch. Then, the node optical switch branches the wavelength multiplexed optical signal at a predetermined branching ratio, selects and outputs a desired wavelength signal from each of the branched wavelength multiplexed optical signals, and the control unit responds to the attribute of the optical path. Set the branching ratio.

  The optical switch method of the present invention is an optical switch method for switching an optical path, accepts a wavelength multiplexed optical signal, sets a branching ratio when branching the wavelength multiplexed optical signal according to the attribute of the optical path, and branches A desired wavelength signal is selected from each wavelength multiplexed optical signal branched by the ratio.

  According to the node optical switching device and the optical switching method of the present invention, it is possible to suppress an increase in loss of the optical node device corresponding to the CDC (Colorless, Directionless, Contentionless) function.

It is a block diagram which shows the structure of the node optical switch apparatus which concerns on the 1st Embodiment of this invention. It is the schematic which shows typically the structure of the optical network where the optical node apparatus which concerns on the 1st Embodiment of this invention is used. It is a block diagram which shows the structure of the optical node apparatus which concerns on the 1st Embodiment of this invention. It is a block diagram which shows the structure of the node optical switch with which the node optical switch apparatus which concerns on the 2nd Embodiment of this invention is provided. It is a block diagram which shows the structure of the splitter with which the node optical switch which concerns on the 2nd Embodiment of this invention is provided. It is a flowchart for demonstrating operation | movement of the node optical switch apparatus which concerns on the 2nd Embodiment of this invention, and an optical node apparatus using the same. It is a block diagram which shows the structure of the optical node apparatus for demonstrating operation | movement of the optical node apparatus which concerns on the 2nd Embodiment of this invention. It is a block diagram which shows the structure of the node optical switch for demonstrating operation | movement of the optical node apparatus which concerns on the 2nd Embodiment of this invention. It is a block diagram which shows the structure of the splitter for demonstrating operation | movement of the optical node apparatus which concerns on the 2nd Embodiment of this invention. It is the schematic which shows typically the structure of the optical network for demonstrating another operation | movement of a related optical node apparatus. It is the schematic which shows typically the structure of the optical network for demonstrating another operation | movement of the optical node apparatus which concerns on the 2nd Embodiment of this invention. It is the schematic which shows typically the structure of the optical network for demonstrating another operation | movement of a related optical node apparatus. It is the schematic which shows typically the structure of the optical network for demonstrating another operation | movement of the optical node apparatus which concerns on the 2nd Embodiment of this invention. It is a block diagram which shows the structure of the node optical switch apparatus which concerns on the 3rd Embodiment of this invention, and an optical node apparatus using the same. It is a block diagram which shows the structure of the node optical switch for demonstrating operation | movement of the node optical switch apparatus which concerns on the 3rd Embodiment of this invention. It is a block diagram which shows the structure of a related node. It is a block diagram which shows the structure of the A input 1 output switch used with a related node.

  Embodiments of the present invention will be described below with reference to the drawings.

[First Embodiment]
FIG. 1 is a block diagram showing a configuration of a node optical switch device 1100 according to the first embodiment of the present invention. The node optical switch device 1100 is used for an optical node device that terminates an optical path, and includes a node optical switch 1110 that receives a wavelength-multiplexed optical signal, and a control unit 1120 that controls the node optical switch 1110.

  The node optical switch 1110 branches the wavelength multiplexed optical signal S110 at a predetermined branching ratio, selects a desired wavelength signal S120 from the branched wavelength multiplexed optical signals, and outputs it. The control unit 1120 sets the branching ratio according to the attribute of the optical path.

  Thus, in the node optical switch device 1100 according to the present embodiment, the control unit 1120 is configured to set the branching ratio of the node optical switch 1110 according to the attribute of the optical path.

  In the optical switch method for switching an optical path according to the present embodiment, first, a wavelength-multiplexed optical signal is received, and a branching ratio for branching the wavelength-multiplexed optical signal is set according to the attribute of the optical path. Then, a desired wavelength signal is selected from each wavelength multiplexed optical signal branched at this branching ratio.

  By adopting such a configuration, it becomes possible to branch the wavelength multiplexed optical signal into only the number required for the optical node device to terminate a desired optical path. Therefore, loss due to branching can be minimized. As a result, according to the node optical switch device 1100 and the optical switch method according to the present embodiment, an increase in the loss of the optical node device can be suppressed.

  Next, an optical node device using the node optical switch device 1100 according to the present embodiment will be described.

  FIG. 2 schematically shows a configuration of an optical network 5000 in which the optical node device according to the present embodiment is used. The optical network 5000 includes, for example, a 4 × 4 mesh network 5100 in which 16 nodes N1 to N16 are connected in a mesh shape, and an optical network management device 5200. The optical node device 1000 according to the present embodiment is arranged in each of the nodes N1 to N16, and the nodes are connected by an optical transmission line 5120.

  The optical network management device 5200 receives a path setting request from a client and performs a route search. Then, based on the result of the route search, instructions such as switching of switches in the optical node device are given to each node. In FIG. 2, a 4 × 4 mesh network is shown as an example. However, the present invention is not limited to this, and the optical node device according to the present embodiment is used even in an optical network having other configurations such as a ring network and a multi-ring network. be able to.

  FIG. 3 shows a configuration of the optical node device 1000 according to the present embodiment. The optical node device 1000 includes the node optical switch device 1100, the network optical switch 1200, the wavelength tunable transponder 1300, and the node control unit 1400 described above.

  The network optical switch 1200 is connected to the optical transmission line 5120 and the node optical switch device 1100 that constitute the optical network. The network optical switch 1200 switches the wavelength-multiplexed optical signal received from the optical transmission line 5120 in units of wavelengths as light and sends it again to the optical transmission line. At the same time, the wavelength multiplexed optical signal branched from the optical transmission line 5120 at this node is switched in wavelength units and output to the branch / insert port. Further, a wavelength-multiplexed optical signal to be inserted into the optical transmission line 5120 at this node is received by the branch / insertion port, switched in units of wavelengths, and sent to the optical transmission line 5120.

  As the network optical switch 1200, a wavelength selective switch can be used. For example, the wavelength selective switch is configured to demultiplex a wavelength-multiplexed optical signal from an optical fiber with a grating and re-input to an arbitrary grating using a micromirror configured with MEMS (Micro Electro Mechanical Systems). be able to. By adopting such a configuration, it is possible to realize path switching in units of wavelengths.

  The node optical switch device 1100 connects an arbitrary port of the optical transmission line side port 1101 and an arbitrary port of the transponder side port 1102 in units of wavelengths. The wavelength variable transponder 1300 is connected to the transponder side port 1102 of the node optical switch apparatus 1100, and receives or transmits an optical signal having an arbitrary wavelength.

  With this configuration, according to the optical node device 1000 of the present embodiment, wavelength-independent (colorless), route-independent (directionless), and collision avoidance (contentionless: Three characteristics (CDC) called “Contentionless” can be realized.

  Here, the node control unit 1400 included in the optical node device 1000 of the present embodiment receives an instruction from the optical network management device that manages the optical network, and receives the node optical switch device 1100, the network optical switch 1200, and the wavelength tunable transponder 1300. To control. At this time, the node control unit 1400 acquires an optical path setting request including an optical path attribute from the optical network management apparatus, and notifies the control unit 1120 included in the node optical switch apparatus 1100 of the acquired optical path attribute.

  As described above, according to the node optical switch device 1100 of the present embodiment, the optical node device 1000 can branch as many as necessary to terminate a desired optical path, thereby minimizing loss due to branching. It can be. As a result, according to the node optical switch device 1100 and the optical node device 1000 using the same according to the present embodiment, an increase in loss of the optical node device corresponding to the CDC (Colorless, Directionless, Contentionless) function can be suppressed. .

[Second Embodiment]
Next, a second embodiment of the present invention will be described. The node optical switch device according to the present embodiment includes a node optical switch 1110 and a control unit 1120, similarly to the node optical switch device 1100 according to the first embodiment.

  FIG. 4 shows a configuration of a node optical switch 1110 according to the second embodiment of the present invention. The node optical switch 1110 includes a plurality of splitters 100 with variable branching ratios for branching wavelength-multiplexed optical signals, and a selector 200 with variable branching ratios for selecting one of the wavelength-multiplexed optical signals branched by the plurality of splitters 100. Is provided. Furthermore, an optical waveguide 300 that connects the splitter 100 and the selector 200, and a wavelength tunable filter 400 that passes an optical signal having a desired wavelength among the wavelength multiplexed optical signals selected by the selector 200 are provided.

  As shown in FIG. 4, the node optical switch 1110 has a switch configuration based on a split-and-select method. Therefore, it is possible to switch a wavelength multiplexed optical signal from an arbitrary port without route restriction, wavelength restriction, and wavelength competition. That is, according to the node optical switch 1110, three characteristics (CDC) of wavelength independence (colorless), route independence (directionless), and collision avoidance (contentionless) are realized. be able to.

  FIG. 4 shows a switch configuration with 8 inputs and 8 outputs (8 × 8) in order to explain the operation of the node optical switch 1110. However, the number of input / output ports is not limited to this.

  In the configuration illustrated in FIG. 4, the node optical switch 1110 includes a 1: 8 splitter 100 that branches the wavelength multiplexed optical signal from the optical transmission line side port 1101, and one of the branched wavelength multiplexed optical signals from each splitter 100. An 8: 1 selector 200 for selecting one. Furthermore, an optical waveguide 300 that connects the splitter 100 and the selector 200, and a wavelength tunable filter 400 that extracts an arbitrary wavelength from the wavelength multiplexed optical signal from the selector 200 and outputs the extracted wavelength to the transponder side port 1102 are provided. Here, the wavelength tunable filter 400 is used to extract an arbitrary wavelength to the transponder side port 1102, but the present invention is not limited to this, and a digital coherent reception technique may be used.

  As a switch element used for the node optical switch 1110, a MEMS optical switch, a LCOS (Liquid Crystal On Silicon) optical switch, a PLC (Planar Lightwave Circuit) optical switch, a silicon photonics optical switch, or the like can be used. Here, the MEMS optical switch switches the optical path by changing the angle of the micromirror formed on the silicon substrate. The LCOS optical switch switches an optical path by changing a reflection angle of incident light by changing a refractive index of a liquid crystal layer formed on a silicon substrate. The PLC optical switch configures a Mach-Zehnder interferometer with a quartz optical waveguide on a silicon substrate to control light passage / non-passage. In the silicon photonics optical switch, a Mach-Zehnder (MZ) interferometer is configured with a silicon optical waveguide on a silicon substrate to control light passage / non-passage.

  FIG. 5 shows the configuration of the splitter 100. FIG. 5 shows a configuration of a splitter 100 having one input and eight outputs (1: 8) using an MZ interferometer optical switch 110 used in a PLC optical switch or a silicon photonics optical switch.

  The MZ interferometer type optical switch 110 includes two optical couplers 111 and 112, an equal-length splitter optical waveguide 113 connecting the optical couplers, and a phase shifter 114 that changes the refractive index of the splitter optical waveguide 113. The input optical signal is branched into two (50:50) by the front-stage optical coupler 111 and joined again by the rear-stage optical coupler 112. At this time, when the phase shifter 114 is not driven, a 100% optical signal is output from the cross port of the MZ interferometer type optical switch 110. On the other hand, when the phase shifter 114 is driven, the speed of the optical signal guided through the splitter optical waveguide 113 changes, and a phase difference is generated when the optical coupler 112 is joined at the subsequent stage. By adjusting this phase difference, a 100% optical signal can be output from the bar port. Further, by changing the phase difference, it is possible to output an optical signal by 50% to the bar port and the cross port.

  That is, when all the MZ interferometer type optical switches 110 are set to 100% output, the input port and the output port are connected in a one-to-one (1: 1) manner. On the other hand, if all the MZ interferometer type optical switches 110 are set to 50% output, the output is 8 ports with respect to one input port, so that the connection is 1: 8 (1: 8). Similarly, a configuration in which one-to-two (1: 2) and one-to-four (1: 4) connections are possible, and connection can be made at an arbitrary branching ratio. Note that by switching the input port and output port of the splitter 100, an 8-to-1 (8: 1) selector 200 can be realized.

  The phase shifter 114 includes a thermo-optical effect type that changes the refractive index of the optical waveguide using a heater or the like, and an electro-optical effect type that changes the refractive index by applying a voltage to the optical waveguide. However, the quartz optical waveguide used for the PLC optical switch and the silicon optical waveguide used for the silicon photonics optical switch have a small refractive index change due to the electro-optic effect, so it is desirable to use a thermo-optic effect type phase shifter.

  Next, the operation of the node optical switch device 1100 according to the present embodiment and the optical node device 1000 using the same will be described. FIG. 6 is a flowchart for explaining the operation of the node optical switch device 1100 according to the present embodiment and the optical node device 1000 using the same.

  Here, the optical network 5000 shown in FIG. 2 will be described as an example. The optical network management device 5200 receives a path setting request from the client (step S210). At this time, the optical network management device 5200 performs a route search in consideration of the branching ratio of the node optical switch 1110 included in the node optical switch device 1100 (step S220). Then, based on the result of the route search at this time, the node optical switch device 1100 is instructed to switch the switch (step S230).

  Next, the node control unit 1400 (see FIG. 3) included in the optical node device 1000 controls each device of the optical node device 1000 so that a desired port is connected in accordance with an instruction from the optical network management device 5200. That is, it instructs the node optical switch device 1100, the network optical switch 1200, and the wavelength tunable transponder 1300 to switch ports (step S240).

  Here, as an example, as shown in FIG. 7, the optical node device 1000 branches an optical signal of wavelength λ1 from the optical transmission line 1 to the wavelength tunable transponder 1, and sends an optical signal of wavelength λ2 from the optical transmission line 1 to the variable wavelength. The operation branching to the transponder 2 will be described. First, the network optical switch 1200 accepts wavelength multiplexed optical signals (λ1, λ2,..., Λn) from the optical transmission line 1, extracts only the optical signals of wavelengths λ1, λ2, and outputs them to the branch / insert port 1. (Step S250 in FIG. 6).

  Next, the node optical switch 1110 included in the node optical switch apparatus 1100 receives the wavelength multiplexed optical signal (λ1, λ2) from the branch / insert port 1 of the network optical switch 1200 at the port 1 of the optical transmission line side port 1101. At this time, as shown in FIG. 8, the node optical switch 1110 connects the optical signal having the wavelength λ1 to the port 1 of the transponder side port 1102 to which the wavelength tunable transponder 1 is connected, and the optical signal having the wavelength λ2 to the wavelength tunable transponder. 2 is connected to the connected port 2 (step S260 in FIG. 6).

  The operation of the splitter 100 included in the node optical switch 1110 at this time will be described with reference to FIG. In the example in this case, since there are two port outputs for one port input, the splitter 100 performs a two-branch operation. Wavelength multiplexed optical signals (λ1, λ2) input from port 1 are output only to the cross port by setting the first-stage switch element 101 to output 100% to the cross port. Similarly, the second stage switch element 102 is set to output 100% to the cross port, and the branch ratio is set so that the third stage switch element 103 outputs 50% to the cross port and 50% to the bar port. (Step S270 in FIG. 6). As a result, the wavelength multiplexed optical signals (λ1, λ2) are output to the output port 1 and the output port 2, respectively.

  Next, by setting the wavelength tunable filter 400 (step S280 in FIG. 6), an optical signal having the wavelength λ1 is output to the output port 1 of the variable wavelength filter 400, and an optical signal having the wavelength λ2 is output to the output port 2.

  With the above operation, the optical signal having the wavelength λ1 can be output from the node optical switch device 1100 to the wavelength tunable transponder 1, and the optical signal having the wavelength λ2 can be output to the wavelength tunable transponder 2.

  In the above description, a case where the node optical switch 1110 performs a two-branch operation is shown as an example, but a four-branch and eight-branch operation can be performed in the same manner. Further, the insertion operation from the arbitrary wavelength variable transponder 1300 to the arbitrary optical transmission line 5120 can be performed in the same manner.

  As described above, according to the node optical switch 1110 of the present embodiment, it is possible to branch the wavelength multiplexed optical signal by the number necessary for the optical node device to terminate a desired optical path. Therefore, loss due to branching can be minimized. As a result, an increase in the loss of the optical node device corresponding to the CDC (Colorless, Directionless, Contentionless) function can be suppressed.

  Next, the operation of the optical node device 1000 using the node optical switch device 1100 according to the present embodiment will be described in more detail. Since the node optical switch device 1100 according to the present embodiment can arbitrarily set a branching ratio, it is possible to efficiently accommodate an optical path as described below.

  First, the case where an optical path is accommodated without considering the branching ratio will be described with reference to FIG. In FIG. 10, a case where the configuration of the optical network is a 4 × 4 mesh network will be described as an example. Here, the reach of the optical path from the node 1 (N1) is limited by the deterioration of the S / N (signal / noise) ratio of the optical signal due to the branch loss. In FIG. 10, the range in which the optical path can be reached by 8 branches is a 3 × 3 range (solid line portion), and the range in which the optical path can be reached by 4 branches is a 4 × 4 range (dotted line portion).

  In the configuration of the optical network shown in FIG. 10, a description will be given of a case where there is a request for 8 paths from the node 1 (N1) to the node 10 (N10) and a request for 2 paths from the node 1 (N1) to the node 14 (N14). To do. In this case, if one path of the optical path for the node 14 (N14) is accommodated in the fiber 1 of the node 1 (N1), the fiber 1 is limited to four branches, and thus cannot be eight branches. Therefore, the remaining optical paths for the node 10 (N10) can be accommodated in the fiber 1 only.

  The same applies to the fiber 2. Therefore, the total of the fibers 1 and 2 can accommodate only 6 paths for the node 10 (N10) and 2 paths for the node 14 (N14). Therefore, the fiber 3 is required to accommodate the remaining two optical paths for the remaining node 10 (N10) in the path setting request. That is, it is necessary to use a total of three fibers.

  Next, a case where an optical path is set by the optical node device 1000 including the node optical switch device 1100 according to the present embodiment will be described with reference to FIG. The configuration of the optical network and the path request are the same as described above.

  Here, in the node optical switch device 1100 according to the present embodiment, the control unit sets the branching ratio of the node optical switch according to the attribute of the optical path. In the following, a case will be described in which the optical path attribute is the optical path reachable distance, and the optical path reachable distance is determined based on the number of hops of the optical path.

  In this case, as shown in FIG. 11, the optical node device 1000 according to the present embodiment accommodates a path for the node 14 (N14) having a large number of hops of the optical path, that is, a long distance between the optical paths, in the fiber 1. . The fibers 2 can collectively accommodate paths for the node 10 (N10) having a small number of hops of the optical path, that is, a short distance between the optical paths. This makes it possible to accommodate all path setting requests with two fibers.

  As described above, the node optical switch device 1100 of the present embodiment is configured to set the branching ratio of the node optical switch according to the optical path reachability determined based on the number of hops of the optical path. With this configuration, according to the optical node device 1000 including the node optical switch device 1100 of the present embodiment, it becomes possible to efficiently accommodate optical paths.

  In the above embodiment, the configuration in which the node optical switch apparatus 1100 sets the branching ratio of the node optical switch according to the reach of the optical path determined based on the number of hops of the optical path has been described. However, the configuration of the node optical switch device 1100 is not limited to this. Hereinafter, a configuration in which the node optical switch apparatus 1100 sets the branching ratio of the node optical switch in accordance with the reach of the optical path determined based on the signal format of the optical path will be described.

  Here, the case where the configuration of the optical network is a 3 × 3 mesh network in which the nodes 1 (N1) to 9 (N9) are connected in a mesh shape will be described as an example. The wavelength variable transponder 1300 (see FIG. 3) included in the optical node device 1000 has a configuration in which different signal formats can be transmitted and received. Here, the signal format includes, for example, DP-QPSK (Dual Polarization-Quadrature Phase Shift Keying) and 16-QAM (Quadrature Amplitude Modulation).

  Here, the reach of the optical path from the node 1 (N1) is limited by the deterioration of the S / N (signal / noise) ratio of the optical signal due to the branch loss. In FIG. 12, when DP-QPSK is used as the signal format, the optical path can reach the range of 3 × 3 with 8 branches, and when 16-QAM is used as the signal format, the optical path has 3 branches with 4 branches. It is assumed that the range of x3 is reachable. In the configuration of the optical network shown in FIG. 12, from the node 1 (N1) to the node 8 (N8), there are 6 paths for the optical path whose signal format is DP-QPSK and 2 paths for the optical path whose signal format is 16-QAM. A case where there is a request will be described.

  First, the case where an optical path is accommodated without considering the branching ratio will be described with reference to FIG. In this case, if one path of 16-QAM optical path is accommodated in the fiber 1 of the node 1 (N1), the fiber 1 is limited to four branches, and thus cannot be eight branches. For this reason, the fiber 1 can accommodate only the remaining three paths even if it is a DP-QPSK optical path. The same applies to the fiber 2. Therefore, the total of the fiber 1 and the fiber 2 can accommodate only 6 paths of DP-QPSK optical paths and 2 paths of 16-QAM optical paths for the node 8 (N8). Therefore, the fiber 3 is necessary to accommodate one path of the 16-QAM optical path for the remaining node 8 (N8) in the path setting request. That is, it is necessary to use a total of three fibers.

  Next, a case where an optical path is set by the optical node device 1000 including the node optical switch device 1100 according to the present embodiment will be described with reference to FIG. The configuration of the optical network and the path request are the same as described above.

  Here, the node optical switch apparatus 1100 according to the present embodiment sets the branching ratio of the node optical switch according to the reach of the optical path determined based on the signal format of the optical path. In this case, the optical node device 1000 can accommodate the DP-QPSK optical path in the fiber 1 and the 16-QAM optical path in the fiber 2 as shown in FIG. This makes it possible to accommodate all path setting requests with two fibers.

  As described above, the node optical switch device 1100 according to the present embodiment is configured to set the branching ratio of the node optical switch according to the optical path reachability determined based on the signal format of the optical path. With this configuration, according to the optical node device 1000 including the node optical switch device 1100 of the present embodiment, it becomes possible to efficiently accommodate optical paths.

[Third Embodiment]
Next, a third embodiment of the present invention will be described. FIG. 14 is a block diagram showing a configuration of a node optical switch device 2100 and an optical node device 2000 using the same according to the third embodiment of the present invention.

  The node optical switch apparatus 2100 according to the present embodiment is used in an optical node apparatus that terminates an optical path, and includes a node optical switch 1110 that receives a wavelength-multiplexed optical signal, and a control unit 1120. The node optical switch 1110 branches the wavelength multiplexed optical signal at a predetermined branching ratio, selects a desired wavelength signal from the branched wavelength multiplexed optical signals, and outputs the selected wavelength signal.

  The node optical switch device 2100 further includes an optical amplifier 2110 disposed at least one of the front and rear stages of the node optical switch 1110. FIG. 14 shows a case where the optical amplifier 2110 is arranged in front of the node optical switch 1110.

  The control unit 1120 controls the node optical switch 1110 and the optical amplifier 2110. Specifically, the control unit 1120 sets the branching ratio of the node optical switch 1110 according to the attribute of the optical path, and sets the amplification factor of the optical amplifier 2110 according to the branching ratio at this time.

  The optical node device 2000 includes the node optical switch device 2100, the network optical switch 1200, the wavelength tunable transponder 1300, and the node control unit 1400 described above. Since the configuration other than the node optical switch device 2100 is the same as that of the optical node device 1000 in the first and second embodiments, a description thereof will be omitted.

  Next, the operation of the node optical switch apparatus 2100 according to the present embodiment will be described with reference to FIG. FIG. 15 is a block diagram illustrating a configuration of a node optical switch 1110 included in the node optical switch apparatus 2100.

  Here, a case where an optical signal is input to and output from the node optical switch 1110 as shown in FIG. 15 will be described as an example. That is, optical signals with wavelengths λ1 to λ3 are input to the optical transmission line side port 1101 of the node optical switch 1110, and optical signals with wavelength λ4 are input to the port 4. Then, an optical signal with wavelength λ1 is output to port 1 of the transponder side port 1102, an optical signal with wavelength λ4 is output to port 2, λ3 to port 3, and λ4 to port 5.

  As shown in FIG. 14, the optical signal passes through the optical transmission line 5120, the network optical switch 1200, and the node optical switch device 2100 and is input to the wavelength tunable transponder 1300. In this path, the optical signal is attenuated by the transmission loss of each device. Further, the wavelength tunable transponder 1300 has a predetermined dynamic range (for example, 0 dBm to −10 dBm), and the optical power of the input light needs to be within that range. Therefore, it is necessary to install an optical amplifier in the above-described path to compensate for the loss.

  At this time, in the example shown in FIG. 15, the optical signals of the wavelengths λ1, λ2, and λ3 are branched into three, but the optical signal of the wavelength λ4 is not branched, so the branching loss is different. Here, the node optical switch device 2100 of the present embodiment is configured such that the control unit 1120 sets the amplification factor of the optical amplifier 2110 according to the branching ratio. Therefore, according to the node optical switch device 2100 of this embodiment, the amount of light compensated by the optical amplifier 2110 can be minimized, and the power saving of the optical node device 2000 can be achieved.

  As described above, in the node optical switch device 2100 of this embodiment, the control unit 1120 sets the branching ratio of the node optical switch 1110 according to the attribute of the optical path, and the optical amplifier 2110 according to the branching ratio at this time. The amplification factor is set. As a result, an increase in loss of the optical node device corresponding to the CDC (Colorless, Directionless, Contentionless) function can be suppressed, and power saving of the optical node device can be achieved.

  The present invention is not limited to the above-described embodiment, and various modifications are possible within the scope of the invention described in the claims, and it is also included within the scope of the present invention. Not too long.

1000, 2000 Optical node device 1100, 2100 Node optical switch device 1101 Optical transmission line side port 1102 Transponder side port 1110 Node optical switch 1120 Control unit 1200 Network optical switch 1300 Wavelength variable transponder 1400 Node control unit 2110 Optical amplifier 5000 Optical network 5100 Mesh network 5120 Optical transmission line 5200 Optical network management apparatus 100 Splitter 101 First stage switch element 102 Second stage switch element 103 Third stage switch element 110 MZ interferometer type optical switch 111, 112 Optical coupler 113 Splitter optical waveguide 114 Phase shifter 200 Selector 300 Optical Waveguide 400 Wavelength Tunable Filter 1-1 to 1-J, 5-1 to 5-J, 36, 37, 38-1 Long-division multiplexed optical signals 2-1 to 2-K Input side optical fiber transmission lines 3 Optical cross-connect units 4-1 to 4-K Output side optical fiber transmission lines 21-1 to 21-K Optical couplers 30, 31 Optical signals Terminating device 31-1 to 31-K optical amplifier 32-1 to 32-K optical coupler 33-1 to 33-L fiber selection switch 34-1 variable optical filter 35-1 to 35-L receiver 40 1 × 2 switch

Claims (10)

A node optical switch device used in an optical node device for terminating an optical path,
A node optical switch that accepts wavelength-multiplexed optical signals;
A control unit for controlling the node optical switch,
The node optical switch branches the wavelength-multiplexed optical signal at a predetermined branching ratio, selects a desired wavelength signal from each branched wavelength-multiplexed optical signal, and outputs it,
The said control part is a node optical switch apparatus which sets the said branching ratio according to the attribute of the said optical path. The node optical switch apparatus according to claim 1, wherein the attribute of the optical path is a reach distance of the optical path. The node optical switch device according to claim 2, wherein the reach distance of the optical path is determined based on the number of hops of the optical path. The node optical switch apparatus according to claim 2, wherein the reach distance of the optical path is determined based on a signal format of the optical path. An optical amplifier disposed in at least one of a front stage and a rear stage of the node optical switch;
The node optical switch device according to any one of claims 1 to 4, wherein the control unit sets an amplification factor of the optical amplifier according to the branching ratio. The node optical switch is:
A plurality of splitters with variable branching ratios for branching the wavelength multiplexed optical signal;
A selector having a variable branching ratio for selecting one from the wavelength multiplexed optical signals branched by the plurality of splitters;
An optical waveguide connecting the splitter and the selector;
6. The node optical switch device according to claim 1, further comprising: a wavelength tunable filter that passes an optical signal having a desired wavelength among the wavelength multiplexed optical signals selected by the selector. The node optical switch device according to any one of claims 1 to 6,
An optical transmission line constituting an optical network and a network optical switch connected to the node optical switch device;
A wavelength tunable transponder connected to the node optical switch device;
A node control unit that controls the node optical switch device, the network optical switch, and the wavelength tunable transponder;
The node control unit acquires an optical path setting request including an attribute of the optical path from an optical network management apparatus that manages the optical network, and notifies the control unit of the acquired attribute of the optical path . An optical switch method for switching an optical path,
Accepts wavelength multiplexed optical signals,
A branching ratio when branching the wavelength multiplexed optical signal is set according to the attribute of the optical path,
An optical switch method for selecting a desired wavelength signal from each wavelength multiplexed optical signal branched at the branching ratio. The attribute of the optical path is a reach distance of the optical path,
The optical switch method according to claim 8, wherein the reach distance of the optical path is determined based on the number of hops of the optical path and a signal format of the optical path. Amplifying the wavelength multiplexed optical signal before branching the wavelength multiplexed optical signal;
The optical switch method according to any one of claims 7 to 9, wherein an amplification factor when the wavelength multiplexed optical signal is amplified is set according to the branching ratio.

Images