Wavelength cross-connect device and wavelength cross-connect method

Abstract

A wavelength cross-connect device (1) is configured to include: input-end WSSs (11a to 11m); wavelength band switch processing units (#1 to #j) that convert the wavelength bands of specific wavelength multiplexed signal beams, which are among wavelength multiplexed signal beams obtained as a result of branching at the input-end WSSs, into different wavelength bands; and output-end WSSs (12a to 12m) that are connected in a mesh topology to the input-end WSSs (11a to 11m) so as to receive the wavelength multiplexed signal beams the wavelength bands of which have been converted and to directly receive unconverted wavelength multiplexed signal beams among the wavelength multiplexed signal beams obtained as a result of the branching.

Description

[Technical field]

[0001] The present invention relates to a wavelength cross-connect device and a wavelength cross-connect method used in multiband transmission in which wavelength-multiplexed signal light, in which optical signals in different wavelength bands are multiplexed, is transmitted over an optical fiber. [Background technology]

[0002] A wavelength cross-connect device used in a multiband transmission system is an optical node that connects arbitrary paths in an optical network to an optical transmission path consisting of one or more optical fibers or multi-core fibers that transmit wavelength multiplexed signal light obtained by multiplexing optical signals of different wavelength bands. In this wavelength cross-connect device, wavelength multiplexed signal light transmitted from an input path is output to an arbitrary output path via multiple WSSs (Wavelength Selective Switches).

[0003] A conventional wavelength cross-connect device first demultiplexes optical signals of each wavelength band of a wavelength multiplexed signal light transmitted in multibands for each of M routes on the input side. For example, it demultiplexes optical signals of each wavelength band of S-band, C-band, and L-band multiplexed in the wavelength multiplexed signal light.

[0004] However, the wavelength bands are, from shortest to longest, the S band of 1460nm to 1530nm, the C band of 1530nm to 1565nm, and the L band of 1565nm to 1625nm. The S, C, and L band optical signals are assigned to the S, C, and L bands of optical fibers as their paths during transmission.

[0005] The demultiplexed optical signals of the S, C, and L bands (each wavelength band) are input to each WXC (Wavelength Cross Connect) section provided for each wavelength band. In each WXC, the WSS for each wavelength band arranged on the input side of the WXC performs processing such as attenuation adjustment for the optical signals of each wavelength band, and the optical signals are input to the WSS for each wavelength band on the output side that is mesh-connected to the WSS on the input side. The input optical signals of the S, C, and L bands are multiplexed in the WSS on the output side, and the wavelength-multiplexed signal light resulting from this multiplexing is transmitted in multiband to M output routes.

[0006] A conventional technique related to this type of wavelength cross-connect device is described in Non-Patent Document 1. [Prior art documents] [Non-patent literature]

[0007] [Non-Patent Document 1] A. Napoli, et al., “Perspectives of multi-band optical communication systems,” Proc. OECC 2018, paper 5B3-1, July 2018. Summary of the Invention [Problem to be solved by the invention]

[0008] However, in the above-mentioned conventional wavelength cross-connect device, there is a difference in optical characteristics due to the difference in each wavelength band in the configuration of each WXC for the S band, C band, and L band, so that deviations occur in the transmission performance of each optical signal in the S band, C band, and L band. For example, wavelength band dependency occurs in the transmission band and optical loss, which are the specifications of the WSS and optical amplifier, and this wavelength band dependency causes deviations in the transmission performance of optical signals among the S band, C band, and L band. This deviation reduces the utilization efficiency of each wavelength band in the optical network.

[0009] The present invention has been made in consideration of the above circumstances, and has an objective of suppressing the difference in transmission performance of optical signals in different wavelength bands in an optical network, and improving the utilization efficiency of each wavelength band in the optical network. [Means for solving the problem]

[0010] In order to solve the above problems, the present invention provides a wavelength cross-connect device, which is capable of connecting multiple optical transmission paths each of which is made up of one or more optical fibers, to multiple optical signals that have been transmitted in multiple bands. S-band, C-band, and L-band The optical fiber communication system is characterized in that it comprises a plurality of input-side WSSs (Wavelength Selective Switches) that branch a wavelength-multiplexed signal light in which each optical signal in a wavelength band is multiplexed into a predetermined number of wavelengths and output the branched signal light, a plurality of wavelength band switching processing units that convert the wavelength bands of predetermined wavelength-multiplexed signal light among the wavelength-multiplexed signal light branched for each input-side WSS into different wavelength bands, and a plurality of output-side WSSs that are mesh-connected to the input-side WSSs so that the wavelength-multiplexed signal light converted to the wavelength band among the wavelength-multiplexed signal light branched for each input-side WSS is input, and unconverted wavelength-multiplexed signal light is directly input. Effect of the Invention

[0011] According to the present invention, it is possible to suppress the difference in transmission performance of optical signals in different wavelength bands in an optical network, and to improve the utilization efficiency of each wavelength band in the optical network. [Brief description of the drawings]

[0012] [Figure 1] 1 is a block diagram showing a configuration of a wavelength cross-connect device applied to a multiband transmission system according to an embodiment of the present invention. [Diagram 2] 2 is a block diagram showing a configuration of a wavelength band switching processing unit of a wavelength cross connect device according to an embodiment; FIG. [Diagram 3] 4 is a flowchart for explaining a wavelength cross-connect operation by the wavelength cross-connect device of the embodiment. [Figure 4]1 is a block diagram showing a configuration of a multiband transmission system in which nodes each equipped with a wavelength cross-connect device of an embodiment are connected in a ring shape by optical transmission paths; [Diagram 5] FIG. 5 is a diagram showing a table of different wavelength bands transmitted on each path between nodes in the multiband transmission system shown in FIG. 4. [Figure 6] FIG. 1 is a diagram showing wavelengths for each of S band, C band, and L band, which are different wavelength bands. [Figure 7] FIG. 13 is a diagram illustrating optical signals of different wavelengths in the S band, C band, and L band transmitted between a plurality of nodes for the purpose of explaining the wavelength continuity constraint. [Figure 8] FIG. 11 is an explanatory diagram of a path setting example 1. [Figure 9] 1 is a graph showing optical signal-to-noise ratios (SNRs) in the S, C and L bands. [Figure 10] FIG. 1 is a diagram showing optical signals of different wavelengths in the S band, C band, and L band transmitted between multiple nodes for the purpose of explaining capacity constraints due to inter-band stimulated Raman scattering. [Figure 11] FIG. 11 is an explanatory diagram of a path setting example 2. [Figure 12] 11 is a block diagram showing another configuration of the waveband switching processing unit of the wavelength cross connect device according to the embodiment. FIG. [Figure 13] FIG. 13 is a block diagram showing a configuration of a wavelength cross connect device according to a modified example of the present embodiment. [Figure 14] FIG. 2 is an explanatory diagram of a process of converting a wavelength in a wavelength band into a wavelength in a different wavelength band. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0013] Hereinafter, an embodiment of the present invention will be described with reference to the drawings. However, in all the drawings in this specification, components having corresponding functions are given the same reference numerals, and the description thereof will be omitted as appropriate. <Configuration of the embodiment> FIG. 1 is a block diagram showing a configuration of a wavelength cross-connect device applied to a multiband transmission system according to an embodiment of the present invention.

[0014] The wavelength cross-connect device 1 shown in Fig. 1 is configured to include a WXC unit with waveband switching 10. The WXC unit with waveband switching 10 will also be referred to as the WXC unit 10.

[0015] The WXC unit 10 with wavelength band switching comprises M <1×Q>WSSs (Wavelength Selective Switches) 11a, 11b, ..., 11m which are connected to M input routes indicated by the symbol Mi and to which wavelength-multiplexed signal light 1a, 1b, ..., 1m transmitted in multiband for each input route are input, and M <1×Q>WSSs 11a to 11m on the output side are fully mesh-connected (described later) via a plurality of wavelength band switching processing units #1 to #j.<Q×1> Equipped with WSS12a, 12b, ..., 12m.

[0016] However, the input side <1×Q> WSS11a~11m and the output side<Q×1> In the full mesh connection (mesh connection) with the WSSs 12a to 12m, there are input / output ports that are directly connected without passing through the wavelength band switching processing units #1 to #j, as described later. Also, the input side <1×Q> WSSs 11a to 11m are also referred to as the input side WSSs 11a to 11m, and the output side<Q×1> The WSSs 12a to 12m are also referred to as output side WSSs 12a to 12m.

[0017] The full mesh connection is as follows. However, the explanation will be given excluding wavelength band switching processing units #1 to #j. That is, in the input side WSSs 11a to 11m, the Q output ports (Q output ports) of the first WSS 11a from the top are connected to the N input ports of the second to Mth WSSs 12b to 12m excluding the first one on the output side. In this way, the Q output ports of each of the <1×Q>WSSs 11a to 11m are connected to the N input ports of the output side WSSs 12b to 12m excluding the output side WSS of the same route as the input side WSS.<Q×1> The Q input ports of the WSSs 12a to 12m are connected to the Q input ports of the WSSs 12a to 12m. This connection forms a path along which the wavelength-multiplexed signal light output from the Q output ports of the WSSs 11a to 11m is redirected.

[0018] Furthermore, the WXC unit 10 includes (M-1) sets of wavelength band switching processors #1 to #j, each set consisting of j units, for each input side <1xQ>WSS (e.g., <1xQ>WSS 11a). In other words, the WXC unit 10 includes j×(M-1) wavelength band switching processors. As the WXC unit 10 includes j×(M-1) wavelength band switching processors for M <1xQ>WSSs 11a to 11m, the WXC unit 10 includes a total of j×(M-1)×M wavelength band switching processors.

[0019] The <1×Q>WSS11a connected to the first input path and the <1×Q>WSS11a connected to the second to Mth output paths excluding the first path<Q×1> Between the WSSs 12b to 12m, (M-1) sets of wavelength band switching processors #1 to #j, each set consisting of j pieces, are connected.

[0020] The <1×Q>WSS11b connected to the second input path and the first and third to Mth output paths excluding the second path<Q×1> Between the WSSs 12a and 12c to 12m, (M-1) sets of wavelength band switching processing units #1 to #j, each set consisting of j units, are connected.

[0021] The <1×Q>WSS11m connected to the Mth input path and the 1st to (M-1)th output paths excluding the Mth path are connected to the <1×Q>WSS11m.<Q×1> Between the WSSs 12a to 12(m-1), (M-1) sets of wavelength band switching processors #1 to #j, each set consisting of j pieces, are connected.

[0022] Each of the M routes Mi is composed of one or more optical fibers. In addition, each of the wavelength-multiplexed signal lights 1a to 1m transmitted in multiband for each input route has the wavelength division multiplexing signal light 1a to 1m shown in FIG.<S,C,L> , 1b<S,C,L> , 1m<S,C,L> As shown in FIG. 1, it is assumed that optical signals in the S band, C band, and L band are multiplexed.

[0023] One <1×Q>WSS on the input side (for example, <1×Q>WSS11a) has one input port connected to one input route. Furthermore, <1×Q>WSS11a has Q=(j+1)(M-1) output ports (Q output ports). (j+1)(M-1) is the sum (1+j) of one output port to which no wavelength band switching processor is connected and j output ports to which wavelength band switching processors #1 to #j are connected in the input side <1×Q>WSS11a.<Q×1> The formula is {(j+1)(M-1)} multiplied by the number (M-1) of WSS12b to 12m.

[0024] The output side WSSs 12a to 12m each include (j+1)(M-1)=Q input ports (Q input ports) and one output port.

[0025] Since the input side WSSs 11a to 11m have the same function, the first <1×Q>WSS 11a from the top will be explained as a representative. The first <1×Q>WSS 11a splits the wavelength multiplexed signal light 1a transmitted in multibands (wavelength bands of S band, C band, and L band) into Q branches, and outputs the Q branched wavelength multiplexed signal light 1a from the Q output port.

[0026] Of the (M-1) sets of Q output ports, there is one set = (j+1) output ports. Of these, the wavelength multiplexed signal light 1a output from the first output port is<Q×1> The signal is output to the first input port of WSS12b.

[0027] The wavelength-multiplexed signal light 1a output from the second to (j+1)th output ports is transmitted to the output side via wavelength band switching processing units #1 to #j.<Q×1> The signals are output to the second through (j+1)th input ports of WSS12b.

[0028] Similarly, the wavelength-multiplexed signal light is also output from the other output ports of the (M-1) pairs of Q output ports of the first <1×Q>WSS11a to the output ports other than the second one.<Q×1> The data is output to WSS.

[0029] The output side WSSs 12a to 12m have the same function, and sequentially select the multi-band wavelength multiplexed signal light input from the Q input ports, and output it from one output port to one output route.

[0030] <Configuration of Wavelength Band Switching Processing Unit> Each of the wavelength band switching processing units #1 to #j has the same function. As shown in FIG. 2 as a representative wavelength band switching processing unit #1, the wavelength band switching processing unit #1 includes a wavelength band demultiplexing unit 31, a plurality of input side wavelength band conversion units 32 and 33,<K×K> The WSS 34 includes a plurality of output-side wavelength band converters 35 and 36, and a wavelength band multiplexer 37. However, only the wavelength band switching processor #1 may have the same function, and the wavelength band switching processors #2 to #j may be single wavelength band converters. Also, the number of wavelength band switching processors #1 to #j connected to the Q output ports of the <1×Q>WSSs 11a to 11m shown in FIG. 1 does not have to be the same. For example, the first port may be #j=3, the second port may be #j=5, etc.

[0031] K is the number of wavelength bands, and in this example, K=3 for the S band, C band, and L band.<K×K> The WSS 34 constitutes a specific WSS as recited in the claims. The input-side wavelength band converters 32 and 33 constitute an input-side converter as recited in the claims. The output-side wavelength band converters 35 and 36 constitute an output-side converter as recited in the claims.

[0032] The wavelength band demultiplexing unit 31 demultiplexes the wavelength multiplexed signal light in which optical signals in the S band, C band, and L band are multiplexed and input from the input side WSSs 11a to 11m, and outputs each of the demultiplexed optical signals in the S band, C band, and L band.<K×K> It is assumed that WSS 34 is capable of processing one wavelength band (specific wavelength band).<K×K> The WSS 34 can only process optical signals in a specific wavelength band (C band). Therefore, the demultiplexed C band optical signal is<K×K> This is input into WSS34.

[0033] <K×K> The wavelength band converter 32 on the input side of the WSS 34 converts the S-band optical signal into a C-band optical signal.<K×K> The wavelength band converter 33 converts the optical signal in the L band into an optical signal in the C band and outputs the converted optical signal to the WSS 34.<K×K> Output to WSS34.

[0034] The wavelength band converter 35 on the output side converts the optical signal in the C band into an optical signal in the S band and outputs it to the wavelength band multiplexer 37. The wavelength band converter 36 converts the optical signal in the C band into an optical signal in the L band and outputs it to the wavelength band multiplexer 37.

[0035] <K×K> The WSS 34 performs a process of converting the wavelength band multiplexed into the wavelength multiplexed signal light 1a to 1m input from the optical transmission line Mi on the input side of the wavelength cross-connect device 1 (FIG. 1) into a different wavelength band.

[0036] this<K×K> The WSS 34 has input ports and output ports in the same number as the number of wavelength bands K=3 multiplexed into the wavelength-multiplexed signal light.<K×K> In WSS34, C-band optical signals input from K=3 input ports are output from K=3 output ports connected to wavelength band conversion units 35, 36 or wavelength band multiplexing unit 37 that convert the signals to a specified wavelength band.

[0037] For example, the C-band optical signal demultiplexed by the wavelength band demultiplexing unit 31 is<K×K> After being input to the second input port of WSS 34, it is input from the first output port to wavelength band converter 35, where it is converted into an S-band optical signal. This example is a conversion process for converting a C-band optical signal input from input path Mi into an S-band optical signal and transmitting it to the output optical transmission path Mo (FIG. 1).

[0038] The wavelength band multiplexer 37 multiplexes the optical signals in the S band, C band, and L band, and outputs the multiplexed signals to input ports of predetermined output side WSSs 12a to 12m.

[0039] <Operation of the embodiment> Next, the wavelength cross-connect operation of the wavelength cross-connect device 1 according to the embodiment will be described with reference to the flowchart of FIG.

[0040] In step S1 shown in Fig. 3, the wavelength-multiplexed signal light 1a-1m transmitted in multiband for each of the M input routes shown in Fig. 1 is input to one input port for each of the M <1×Q>WSSs 11a-11m of the wavelength-band-switching WXC unit 10. Note that optical signals in the S band, C band, and L band are multiplexed for each of the wavelength-multiplexed signal light 1a-1m.

[0041] In step S2, each of the <1×Q> WSSs 11a-11m Q-branches each of the wavelength multiplexed signal lights 1a-1m. The Q-branched wavelength multiplexed signal lights are directly output to input ports of predetermined output side WSSs 12a-12m and also output to wavelength band switching processing units #1-#j. However, the WSS does not perform simple Q-branching using a coupler or the like, but has a function of performing Q-branching by outputting each optical signal of the wavelength multiplexed signal light input from an input port from an arbitrary output port.

[0042] In step S3, the wavelength band switching processing units #1 to #j demultiplex the input wavelength multiplexed signal light of the S band, the C band, and the L band in the wavelength band demultiplexing unit 31 shown in FIG. 2, and output the demultiplexed optical signals of the S band, the C band, and the L band. At this time, the optical signal of the C band is left as it is.<K×K> The optical signal in the S band is input to the WSS 34. The optical signal in the L band is output to the wavelength band converter 32, and the optical signal in the L band is output to the wavelength band converter 33.

[0043] In step S4, the wavelength band converter 32 converts the optical signal in the S band into an optical signal in the C band.<K×K> The wavelength band converter 33 converts the optical signal in the L band into an optical signal in the C band and outputs the converted optical signal to the WSS 34.<K×K> The C-band optical signal is output to WSS34 without conversion.<K×K> Output to WSS34.

[0044] In step S5,<K×K> The WSS 34 outputs the C-band optical signals input from K (3) input ports from K output ports required for wavelength band conversion. For example,<K×K> An optical signal in the C band input from the second input port of the WSS 34 is output to the wavelength band converter 35 from the first output port.

[0045] In step S6, the wavelength band converter 35 converts the optical signal in the C band into an optical signal in the S band and outputs it to the wavelength band multiplexer 37. The wavelength band converter 36 converts the optical signal in the C band into an optical signal in the L band and outputs it to the wavelength band multiplexer 37.

[0046] In step S7, the wavelength band multiplexing unit 37 multiplexes the optical signals in the S band, C band, and L band, converts them into wavelength multiplexed signal light, and outputs them to predetermined input ports of the predetermined output side WSSs 12a to 12m shown in Fig. 1. The wavelength multiplexed signal light is redirected by such output.

[0047] In step S8, each of the output WSSs 12a to 12m sequentially selects the wavelength multiplexed signal light in the S band, C band, and L band input from the Q input port, and outputs the selected signal light from one output port to one output route.

[0048] <Effects of the embodiment> The effects of the wavelength cross connect device 1 according to the embodiment of the present invention will be described.

[0049] (1a) The wavelength cross-connect device 1 includes a plurality of input WSSs 11a-11m connected to a plurality of optical transmission paths each consisting of one or more optical fibers, a plurality of wavelength band switching processing units #1-#j, and M output WSSs 12a-12m.

[0050] Each of the input WSSs 11a to 11m branches a wavelength-multiplexed signal light, in which optical signals in different wavelength bands transmitted in multibands are multiplexed for each optical transmission line, into a predetermined number of signals and outputs the branched signals. Each of the wavelength band switching processing units #1 to #j converts the wavelength band of a predetermined wavelength multiplexed signal light among the wavelength multiplexed signal light branched off for each of the input side WSSs 11a to 11m into a different wavelength band.

[0051] Each output WSS 12a to 12m is mesh-connected to the input WSS 11a to 11m so that the wavelength-multiplexed signal light branched off for each input WSS 11a to 11m is input after being converted to the above-mentioned wavelength band, and unconverted wavelength-multiplexed signal light is directly input.

[0052] According to this configuration, the wavelength cross-connect device 1 has input side WSSs 11a-11m, where wavelength multiplexed signal light transmitted in multiband is input and branched, and output side WSSs 12a-12m, which are mesh-connected with multiple wavelength band switching processors #1-#j between them. Therefore, the wavelength multiplexed signal light branched by the input side WSSs 11a-11m is wavelength band converted by the wavelength band switching processors #1-#j, and then output to the mesh-connected output side WSS for route change. In this way, with a simple configuration including multiple wavelength band switching processors #1-#j between the input side WSSs 11a-11m and the output side WSSs 12a-12m, wavelength band conversion and route change of the wavelength multiplexed signal light can be performed.

[0053] Therefore, in a multiband transmission system 40 (FIG. 4) in which a plurality of nodes to which a wavelength cross-connect device is applied are linked and connected, wavelength band conversion can be performed on a link-by-link and wavelength-by-wavelength basis, which will be described later. With this conversion, for example, a wavelength in an empty wavelength band in an optical transmission line between nodes 40a and 40b (for example, wavelength C1 in the C band) can be converted and used in the wavelength cross-connect device 1 on the front side of the section between nodes 40a and 40b. In this way, a wavelength in a wavelength band in an empty wavelength section can be set as available, so that the capacity of the network can be improved. In other words, the network utilization efficiency of the multiband transmission system can be improved.

[0054] The multiband transmission system (also referred to as the system) 40 shown in Figure 4 is configured by connecting nodes 40a, 40b, 40c, 40d, 40e, and 40f, which are communication devices equipped with a wavelength cross-connect device 1, in a ring shape by optical transmission paths 41a, 41b, 41c, 41d, 41e, and 41f made of optical fibers.

[0055] The above-mentioned link unit is a unit of the optical transmission line 41a that connects two adjacent node sections (for example, nodes 40a and 40b) in the system 40. In other words, it is a unit of a section between two adjacent nodes.

[0056] In the conventional technology, when optical signals of different wavelength bands are transmitted in multiple bands through multiple paths between nodes 40a-40b-40c-40d, for example, with node 40a as the start point and node 40d as the end point, through optical transmission lines 41a, 41b, and 41c, transmission is limited to one wavelength band in one path. Note that between nodes 40a-40b-40c-40d is also referred to as between nodes 40a...40d.

[0057] For example, when transmitting S-band, C-band, and L-band optical signals in multiband between nodes 40a...40d, path 1 through optical transmission lines 41a-41c is limited to transmitting only S-band optical signals, path 2 is limited to transmitting only C-band optical signals, and path 3 is limited to transmitting only L-band optical signals.

[0058] Here, multiband transmission has the characteristic that power transitions from optical signals with short wavelengths to optical signals with long wavelengths. For this reason, in the above example, the transmission of optical signals in the S band on path 1 often has poor transmission performance, while the transmission of optical signals in the C band on path 2 has normal transmission performance, and the transmission of optical signals in the L band on path 3 has good transmission performance. In this way, a deviation in transmission performance occurs between paths 1, 2, and 3.

[0059] Transmission performance is determined by parameters such as the transmission band and loss amount as the performance of devices (optical products) such as optical fibers, as well as stimulated Raman scattering (SRS), which is a nonlinear optical effect. The above parameters are highly band-dependent. As transmission performance depends on the wavelength band used as mentioned above, deviations occur between different wavelength bands.

[0060] In contrast to this, in this embodiment, the wavelength cross-connect device 1 can change the wavelength band for each section (link unit) between each of the nodes 40a...40d.

[0061] For example, as shown in Fig. 5, in path 1 between nodes 40a-40b-40c-40d, an S-band optical signal is transmitted in the first section (between nodes 40a-40b), and a C-band optical signal is transmitted in the second section (between nodes 40b-40c). An L-band optical signal is transmitted in the third section (between nodes 40c-40d). In path 2, a C-band optical signal is transmitted in the first section, an L-band optical signal is transmitted in the second section, and an S-band optical signal is transmitted in the third section. In path 3, an L-band optical signal is transmitted in the first section, an S-band optical signal is transmitted in the second section, and a C-band optical signal is transmitted in the third section.

[0062] In this way, when optical signals of different wavelength bands are transmitted for paths 1, 2, and 3 in each section, the transmission performance of the different wavelength bands for paths 1, 2, and 3 in each section is averaged. This averaging suppresses the deviation in transmission performance between paths 1 to 3. This suppression of deviation can improve the network utilization efficiency of the multiband transmission system.

[0063] Next, we will explain the effect of being able to convert wavelength bands on a wavelength-by-wavelength basis. As shown in Figure 6, assume that the S band of an optical signal is made up of wavelengths S1, S2, and S3, the C band is made up of wavelengths C1, C2, and C3, and the L band is made up of wavelengths L1, L2, and L3.

[0064] In the conventional technology, the setting of one wavelength band was limited to one path in the entire section. However, in this embodiment, the wavelength cross-connect device 1 can set any wavelength of different wavelength bands for paths 1, 2, and 3 in each node 40a-40b-40c-40d section. For example, a wavelength S1 in the S band is set for path 1 of the optical transmission line 41a in the node 40a-40b section, a wavelength C1 in the C band is set for path 2 of the optical transmission line 41b in the node 40b-40c section, and a wavelength L1 in the L band is set for path 3 of the optical transmission line 41c in the node 40c-40d section, and optical signals can be transmitted with the set wavelengths S1, C1, and L1.

[0065] In this way, the present embodiment, which allows wavelength band conversion on a wavelength-by-wavelength basis, can avoid the wavelength continuity constraint of the prior art, which is the need for continuous transmission at the same wavelength within one wavelength band on one path between nodes 40a...40d.

[0066] For example, as shown in Fig. 7, assume that wavelengths S1, S2, and S3 in the S band, wavelengths C1, C2, and C3 in the C band, and wavelengths L1, L2, and L3 in the L band are set between each of the nodes 40a...40d in addition to the sections indicated by the five elliptical dashed-line frames. In this case, in the conventional technology, due to the wavelength continuity constraint, the same wavelength of the same path conflicts in the wavelength vacant section indicated by the elliptical dashed-line frame, so the wavelength cannot be used. For example, in the wavelength vacant section indicated by the elliptical dashed-line frame in the C band between the nodes 40a-40b, the wavelength C2 has already been set between the nodes 40b-40d, so the wavelength C2 of the same wavelength that conflicts with it cannot be set.

[0067] However, in this embodiment, since the wavelength cross-connect device 1 can convert the wavelength band on a wavelength-by-wavelength basis, for example, the wavelength C2 shown in the broken ellipse frame in the C band between the nodes 40a and 40b can be set. Furthermore, the wavelength S2 shown in the broken ellipse frame in the S band between the nodes 40b and 40c can be set, and the wavelength L2 shown in the broken ellipse frame in the L band between the nodes 40c and 40d can be set. In this case, an optical signal can be transmitted using the wavelength C2 in the wavelength band C between the nodes 40a and 40b, the wavelength S2 in the wavelength band S between the nodes 40b and 40c, and the wavelength L2 in the wavelength band L between the nodes 40c and 40d.

[0068] In this way, the available wavelengths shown in the dashed ellipse can be used to transmit optical signals while avoiding wavelength collisions, thereby improving the network capacity, i.e., improving the network utilization efficiency of the multiband transmission system.

[0069] Furthermore, such wavelength band conversion on a wavelength-by-wavelength basis can also avoid capacity limitations due to interband stimulated Raman scattering occurring in the S-band.

[0070] <Path setting example 1> Here, a path setting example 1 will be described with reference to FIG. A path setting device 55 is connected to each of the nodes 40a to 40d. An external terminal device 56, such as a personal computer, for performing a path setting order is connected to this path setting device 55. Also, multiple arrows W1 indicate wavelength band switching points.

[0071] The path setting device 55 manages the usage status of the wavelengths between the nodes 40a...40d. For example, when an order to set a new path between the nodes 40a...40d is added by the external terminal 56, a path cannot be set between the nodes 40a...40d using the same wavelength, so the path setting device 55 checks the availability of the wavelength.

[0072] The path setting device 55 issues the following instructions (1) to (4) in response to confirmation of the availability of the wavelength. (1) The path setting device 55 instructs the node 40a to transmit a signal with wavelength C2 in the C band to the node 40b, as indicated by an arrow Y11, in order to set an optical path on the optical transmission line 41a. (2) In order to set up an optical path on the optical transmission line 41b, the path setting device 55 instructs the node 40b to switch the C band of the input optical signal of wavelength C2 to the S band, convert it to an optical signal of wavelength S2 as shown by arrow Y12, and transmit it to the node 40c. (3) In order to set up an optical path on the optical transmission line 41c, the path setting device 55 instructs the node 40c to switch the S band of the input optical signal of wavelength S2 to the L band, convert it to an optical signal of wavelength L2 as shown by arrow Y13, and transmit it to the node 40d. (4) The path setting device 55 may instruct the node 40d to switch back to the wavelength S2 in the S band. This is performed when the wavelength band that can be used is determined at the start point and end point of the path.

[0073] Next, as shown in FIG. 9 , when interband stimulated Raman scattering does not occur in the S band, the C band, and the L band, the optical signal-to-noise ratios {SNR (Signal-to-Noise Ratio) [dB] on the vertical axis} in the S band, the C band, and the L band are approximately the same, as shown by the dashed line 51.

[0074] On the other hand, when interband stimulated Raman scattering occurs, the SNRs of the S, C and L bands decrease as the frequency of the wavelength band increases, in other words, as the wavelength of the wavelength band decreases, as shown by the solid line 52. The SNR is the worst in the S band. For this reason, as shown by the dashed horizontal bars of the reference numeral 54 in Fig. 10, optical signals cannot be transmitted through the S band between nodes 40a-40b-40c-40d.

[0075] However, in this embodiment, since the wavelength cross-connect device 1 can convert the wavelength band on a wavelength-by-wavelength basis, wavelengths of different wavelength bands can be set in the wavelength vacant sections shown in the dashed ellipse frames as follows: That is, a wavelength C3 is set between nodes 40a and 40b, a wavelength S3 is set between nodes 40b and 40c, and a wavelength L3 is set between nodes 40c and 40d. With this setting, the wavelength C3 in the wavelength band C is used between nodes 40a and 40b, the wavelength S3 in the wavelength band S is used between nodes 40b and 40c, and the wavelength L3 in the wavelength band L is used between nodes 40c and 40d, making it possible to transmit optical signals while mitigating the effects of inter-band stimulated Raman scattering.

[0076] <Path setting example 2> Here, a path setting example 2 will be described with reference to Fig. 11. However, similarly to the case shown in Fig. 8, a path setting device 55 to which an external terminal 56 is connected is connected to each of the nodes 40a to 40d.

[0077] The path setting device 55 manages the usage status of wavelengths between the nodes 40a...40d. For example, when an order to set a new path between the nodes 40a...40d is added by the external terminal 56, the path setting device 55 checks the availability of wavelengths. In the example of FIG. 11, it is possible to set a path between the nodes 40a-40d with wavelength S3. However, if the setting conditions stipulate that wavelength S3 can be set to up to two consecutive links, it is not possible to set a path on the optical transmission lines 41a, 41b, and 41c with wavelength S3.

[0078] Therefore, the path setting device 55 issues the instructions described in the following (1) to (4) in response to confirmation of the availability of the above wavelengths. (1) The path setting device 55 instructs the node 40a to transmit an optical signal in the S band with wavelength S3 to the node 40b as indicated by the arrow Y21 in order to set an optical path on the optical transmission line 41a. (2) The path setting device 55 instructs the node 40b to transmit the input optical signal with wavelength S3 as is to the node 40c as indicated by the arrow Y21 in order to set an optical path on the optical transmission line 41b. (3) In order to set up an optical path on the optical transmission line 41c, the path setting device 55 instructs the node 40c to switch the S band of the input optical signal of wavelength S3 to the L band, convert it to an optical signal of wavelength L3 as shown by arrow Y22, and transmit it to the node 40d. (4) The path setting device 55 may instruct the node 40d to switch back to the wavelength S2 in the S band. This is performed when the wavelength band that can be used is determined at the start point and end point of the path.

[0079] As described above, since optical signals can be transmitted between the nodes 40a...40d while avoiding interband stimulated Raman scattering, the capacity constraints due to interband stimulated Raman scattering can also be avoided, thereby improving the usable capacity of the network in the multiband transmission system and improving the utilization efficiency of the network.

[0080] In other words, in general, the network efficiency decreases from 100% due to wavelength continuity constraints, and further decreases due to capacity constraints caused by the influence of inter-band stimulated Raman scattering. However, according to the wavelength cross-connect device 1 of the present embodiment, the decrease in the network efficiency can be suppressed.

[0081] (2a) Waveband switching processing units #1 to #j include a wavelength band demultiplexing unit 31, wavelength band conversion units 32 and 33 as input side conversion units, and a specific WSS.<K×K> The optical fiber 100 includes a WSS 34, wavelength band converters 35 and 36 as output side converters, and a wavelength band multiplexer 37.

[0082] The wavelength band demultiplexing unit 31 demultiplexes and outputs optical signals of different wavelength bands multiplexed into the wavelength multiplexed signal light from one output port of each of the input side WSSs 11a to 11m.

[0083] Wavelength band conversion units 32 and 33 serving as input-side conversion units convert optical signals of wavelength bands other than a predetermined specific wavelength band, among the optical signals of different wavelength bands demultiplexed by wavelength band demultiplexer 31, into optical signals of the specific wavelength band.

[0084] <K×K> The WSS 34 has input ports and output ports in the same number as the number of wavelengths demultiplexed in the wavelength band demultiplexing unit 31, is capable of processing only specific wavelength bands, and outputs from the output port a specific wavelength band converted by the wavelength band conversion units 32, 33 input from the input port, or a specific wavelength band within the different demultiplexed wavelength band, so as to convert it into a predetermined wavelength band.

[0085] Wavelength band converters 35 and 36 serving as output side converters convert optical signals of specific wavelength bands outputted from output ports into optical signals of a predetermined wavelength band. The wavelength band multiplexer 37 multiplexes the optical signals in different wavelength bands from the wavelength band converters 35 and 36, converts them into wavelength multiplexed signal light, and outputs the multiplexed signal light to each of the output WSSs 12a to 12m.

[0086] According to this configuration,<K×K> The WSS 34 converts the specific wavelength band converted by the wavelength band converters 32 and 33 on the input side, or the specific wavelength band within the different wavelength bands demultiplexed by the wavelength band demultiplexer 31, into a predetermined wavelength band and outputs it from the output port.<K×K> Since the WSS 34 can convert optical signals of different wavelength bands into optical signals of a predetermined wavelength band, the wavelength band switching processing units #1 to #j can be made compact.

[0087] <Other configurations of the wavelength band switching processing unit> The wavelength band switching processing units #1 to #j shown in FIG. 1 may be configured as shown in FIG. 2, or may be configured as shown in FIG. 12, with the wavelength band switching processing unit #1 being representative.

[0088] The wavelength band switching processing unit #1 shown in FIG. 12 includes a <1×P> WSS 61, P wavelength band conversion units 62a, 62b, 62c, 62d, 62e, and 62f,<P×1> P is the number of output ports of WSS61 and WSS63.<P×1> The number of input ports of the WSS 63 is the same as the number of the wavelength band conversion units 62a to 62f.

[0089] However, <1×P>WSS61 and<P×1> Either one of the WSSs 63 may be an optical coupler such as a 1×P or P×1 optical fiber coupler. Note that the <1×P> WSS 61 constitutes the first WSS recited in the claims.<P×1> The WSS 63 constitutes the second WSS recited in the claims.

[0090] The <1×P>WSS 61 branches each of the optical signals in different wavelength bands, S, C, and L, multiplexed into the wavelength multiplexed signal light input from the input side WSS 11a (FIG. 1), into P. This P-branching is performed including a predetermined number of optical signals in the same wavelength band. In this example, the optical signals in the S, C, and L bands are branched into P, including two each, as follows: the optical signal in the S band is output to wavelength band converters 62a and 62b, the optical signal in the C band is output to wavelength band converters 62c and 62d, and the optical signal in the L band is output to wavelength band converters 62e and 62d.

[0091] The wavelength band converter 62a converts an S-band optical signal into a C-band optical signal, and the wavelength band converter 62b converts an S-band optical signal into an L-band optical signal.<P×1> The wavelength band converter 62c converts the C-band optical signal into an S-band optical signal, and the wavelength band converter 62d converts the C-band optical signal into an L-band optical signal.<P×1> The wavelength band converter 62e converts the L-band optical signal into an S-band optical signal, and the wavelength band converter 62f converts the L-band optical signal into a C-band optical signal.<P×1> Output to the WSS63 input port.

[0092] <P×1> WSS 63 multiplexes two each of the S band, C band, and L band input to P input ports, converts them into wavelength-multiplexed signal light, and outputs the converted wavelength-multiplexed signal light to output WSSs 12a to 12m shown in Figure 1.

[0093] According to this configuration, the wavelength band switching processing unit #1 having a simple configuration can convert different wavelength bands multiplexed into wavelength multiplexed signal light for each input transmission line into optical signals of other different wavelength bands.

[0094] In addition, the wavelength band switching processing unit #1 shown in FIG. 2 or FIG. 12 may use a WSS that can handle at least two wavelength bands. In addition to the wavelength band switching processing unit #1, the WSSs 11a to 11m on the input side and the WSSs 12a to 12m on the output side of the WXC 10 shown in FIG. 1 may also use a WSS that can handle at least two wavelength bands as a variation of the configuration. For example, instead of the WSS 34 shown in FIG. 2 that can process the S band, the C band, and the L band, a WSS for the S band and a WSS for the C band and the L band may be configured as one set. In addition, when the E band, the S band, the C band, and the L band are used, a configuration may be provided with a WSS for the E band and the S band and a WSS for the C band and the L band. In other words, a configuration that can process half of the four wavelength bands may be used.

[0095] <Modifications of the embodiment> FIG. 13 is a block diagram showing a configuration of a wavelength cross connect device according to a modified embodiment of the present invention.

[0096] The wavelength cross-connect device 1A of the modified example shown in Figure 13 differs from the wavelength cross-connect device 1 of the above embodiment (Figure 1) in that it is equipped with input side WSSs 11aA-11mA and wavelength band conversion units #1A-#jA instead of input side WSSs 11a-11m and wavelength band switching processing units #1-#j (Figure 1).

[0097] Since the input side WSSs 11aA to 11mA have the same function, the first input side WSS 11aA will be described as a representative. The first input side WSS 11aA Q-branches the wavelength multiplexed signal light 1a transmitted in multiple bands (wavelength bands of S band, C band, and L band) into optical signals of any one of the S band, C band, and L band, and outputs an optical signal of any one of the Q branched wavelength bands from any one of the Q output ports. For example, an optical signal of the L band is output from the first output port of the Q output ports, an optical signal of the S band is output from the second output port, and an optical signal of the C band is output from the jth output port.

[0098] The wavelength band converters #1A-#jA are configured to convert a predetermined wavelength band out of the S band, C band, and L band of the wavelength multiplexed signal light 1a-1m branched by the input WSSs 11aA-11mA into a different wavelength band. For example, the wavelength band converter #1A connected to the output port of the input WSS 11aA is configured to convert the S band into the C band, and the wavelength band converter #jA is configured to convert the C band into the L band.

[0099] The optical signal in the L band output from the first output port of the input WSS 11aA is output to the first input port of the output WSS 12b without conversion. The optical signal in the S band output from the second output port is output to wavelength band converter #1A and converted to an optical signal in the C band. The optical signal in the C band output from the jth output port is output to wavelength band converter #jA and converted to an optical signal in the L band.

[0100] The wavelength cross connect device 1A of this modification can also provide the same effects as those of the above-described embodiment. Moreover, the wavelength band converters #1A-#jA of the modification can be configured simpler and more compact than the wavelength band switching processors #1-#j of the embodiment, and therefore the wavelength cross connect device 1A can be made more compact.

[0101] In addition, the wavelength band conversion units #1A to #jA may shift the wavelength of the wavelength multiplexed signal light 1a to 1m in the wavelength band (for example, wavelength S1 in the S band) to the longer or shorter wavelength side and convert it to a wavelength in a different wavelength band (wavelength C2 in the C band).

[0102] This shift is performed by setting as follows. For example, in wavelength band converter #1A connected to input WSS 11aA, the wavelength S1 in the S band of the optical signal is shifted to the longer wavelength side by a shift amount <+3> as shown by arrow Y1 in Fig. 14, and is set to be converted to wavelength C1 in the C band. As a result, the wavelength S1 in the S band of the wavelength multiplexed signal light 1a dropped by input WSS 11aA is converted to wavelength C1 in the C band by wavelength band converter #1A, and output to the second input port of output WSS 12b.

[0103] Similarly, in wavelength band converter #1j connected to input WSS 11aA, the wavelength S2 in the S band of the optical signal is shifted to the longer wavelength side by the shift amount <+4> as shown by arrow Y2 in Fig. 14, and is set to be converted to wavelength C3 in the C band. As a result, the wavelength S2 in the S band of the branched wavelength multiplexed signal light 1a is converted to wavelength C3 in the C band by wavelength band converter #jA and output to the j-th input port of output WSS 12b.

[0104] Also, in the wavelength band converter #1A of the other set (1+j) connected to the input WSS 11a, the L-band wavelength L3 of the optical signal is shifted to the shorter wavelength side by the shift amount <-8> as shown by the arrow Y3 in Fig. 14, and is set to be converted to the S-band wavelength S1. As a result, the L-band wavelength L3 of the branched wavelength multiplexed signal light 1a is converted to the S-band wavelength S1 in the wavelength band converter #1A of the other set (1+j), and is output to the first input port of the other set (1+j) of the output WSS 12b.

[0105] Furthermore, in the wavelength band converter #jA of the other set (1+j) connected to the input WSS 11a, the wavelength C3 in the C band of the optical signal is shifted to the shorter wavelength side by the shift amount <-5> as shown by the arrow Y4 in Fig. 14, and is set to be converted to a wavelength S1 in the S band. As a result, the wavelength C3 in the C band of the branched wavelength multiplexed signal light 1a is converted to a wavelength S1 in the S band in the wavelength band converter #jA of the other set (1+j), and is output to the j-th input port of the other set (1+j) of the output WSS 12b.

[0106] In this manner, the wavelength band conversion units #1A to #jA of the wavelength cross-connect device 1A enable wavelength conversion across a plurality of wavelength bands in the wavelength multiplexed signal lights 1a to 1m on a wavelength-by-wavelength basis.

[0107] According to the above-mentioned wavelength cross-connect device 1, 1A, the usage status of the wavelength band switching processing unit #1-#j or the wavelength band conversion unit #1A-#jA is monitored and the power is dynamically turned off, thereby reducing power consumption during operation. Furthermore, the wavelength shift amount in the wavelength band conversion unit #1A-#jA can be arbitrarily selected, and even if any of the wavelength band conversion units #1A-#jA breaks down, it is possible to suppress the influence of the failure by substituting another conversion processing unit through remote control.

[0108] <Effects> (1) A wavelength cross-connect device comprising: a plurality of input-side WSSs (Wavelength Selective Switches) for each of a plurality of optical transmission paths consisting of one or a plurality of optical fibers, which branch and output a predetermined number of wavelength-multiplexed signal light, in which optical signals of different wavelength bands transmitted in multibands are multiplexed; a plurality of wavelength band switching processing units for converting the wavelength bands of predetermined wavelength-multiplexed signal light among the wavelength-multiplexed signal light branched for each of the input-side WSSs into different wavelength bands; and a plurality of output-side WSSs mesh-connected to the input-side WSSs so that the wavelength-multiplexed signal light converted to the wavelength band among the wavelength-multiplexed signal light branched for each of the input-side WSSs is input, and unconverted wavelength-multiplexed signal light is directly input.

[0109] According to this configuration, the wavelength cross-connect device has an input WSS, where wavelength multiplexed signal light transmitted in multibands is input and branched, and an output WSS, which are mesh-connected between the input WSS and the output WSS via multiple wavelength band switching processors. Therefore, the wavelength multiplexed signal light branched at the input WSS is wavelength band converted at the wavelength band switching processor, and then output to the mesh-connected output WSS, thereby changing the route. In this way, with a simple configuration having multiple wavelength band switching processors between the input WSS and the output WSS, it is possible to perform wavelength band conversion and route change of the wavelength multiplexed signal light.

[0110] In a multiband transmission system in which a plurality of nodes to which the above-mentioned wavelength cross-connect device is applied are link-connected (optical transmission line-connected), wavelength band conversion can be performed on a link-by-link and wavelength-by-wavelength basis. This conversion allows a wavelength in an available wavelength band in an optical transmission line in a node section (for example, wavelength C1 in the C band) to be converted and used in the wavelength cross-connect device on the front side of the node section. In this way, the wavelength in the wavelength band in the available wavelength section can be set as available, thereby improving the capacity of the network. In other words, the network utilization efficiency of the multiband transmission system can be improved.

[0111] (2) The wavelength cross-connect device according to (1) above, characterized in that the wavelength band switching processing unit comprises: a wavelength band demultiplexing unit that demultiplexes and outputs optical signals of different wavelength bands multiplexed into the wavelength multiplexed signal light from the input WSS; an input side conversion unit that converts optical signals of wavelength bands other than a predetermined specific wavelength band from the demultiplexed optical signals of different wavelength bands into optical signals of the specific wavelength band; a specific WSS that has the same number of input ports and output ports as the number of demultiplexes, is capable of processing only the specific wavelength bands, and outputs from the output port so as to convert the specific wavelength band input from the input port and converted by the input side conversion unit, or a specific wavelength band within the demultiplexed different wavelength bands, into a predetermined wavelength band; an output side conversion unit that converts the optical signal of the specific wavelength band output from the output port into an optical signal of the predetermined wavelength band; and a wavelength band combining unit that combines each optical signal of different wavelength bands from the output side conversion unit to convert it into wavelength multiplexed signal light and outputs it to the output side WSS.

[0112] According to this configuration, the specific wavelength band converted by the input-side conversion unit, or the specific wavelength band within the different wavelength bands separated by the wavelength band separation unit, is output from the output port so as to be converted to a predetermined wavelength band by the specific WSS. In this way, the optical signals of different wavelength bands can be converted to optical signals of a predetermined wavelength band by one specific WSS, so that the wavelength band switching processing unit can be made compact.

[0113] (3) The wavelength cross-connect device described in (1) above is characterized in that the wavelength band switching processing unit is configured to include a first WSS that branches different wavelength bands multiplexed into wavelength multiplexed signal light from the input WSS, including a predetermined number of optical signals of the same wavelength band, a number of wavelength band conversion units equal to the number of branches that convert the optical signals of the wavelength bands branched by the first WSS into optical signals of different wavelength bands, and a second WSS that multiplexes the optical signals of each wavelength band converted by the wavelength band conversion units, converts them into wavelength multiplexed signal light, and outputs it to the output WSS.

[0114] According to this configuration, a different wavelength band multiplexed into the wavelength multiplexed signal light for each input transmission line can be converted into an optical signal of another different wavelength band by a wavelength band switching processing section having a simple configuration.

[0115] (4) The wavelength cross-connect device described in (1) above is characterized in that the input side WSS performs a process of branching the wavelength-multiplexed signal light for each optical transmission path into optical signals of any one of the wavelength bands and outputting the optical signals of any one of the branched wavelength bands from any one of the output ports, and is equipped with a wavelength band conversion unit instead of the wavelength band switching processing unit, which converts the optical signal of one wavelength band output from one output port of the input side WSS into a different wavelength band.

[0116] According to this configuration, the wavelength band conversion section has a simpler and smaller configuration than the wavelength band switching processing section, and therefore the wavelength cross connect device can be made smaller accordingly.

[0117] (5) The wavelength band conversion unit is a wavelength cross-connect device described in (4) above, characterized in that it shifts the wavelength of an optical signal in one wavelength band output from one output port of the input side WSS to a wavelength in a different wavelength band by shifting it to the longer wavelength side or the shorter wavelength side.

[0118] According to this configuration, wavelength band conversion is possible in wavelength-multiplexed signal light on a wavelength-by-wavelength basis.

[0119] In addition, the specific configuration can be modified as appropriate without departing from the spirit of the present invention. [Explanation of symbols]

[0120] 1,1A Wavelength Cross-Connect Device 10 WXC section with wavelength band switching 11a~11m <1×Q> WSS (input side WSS) 12a~12m<Q×1> WSS (output side WSS) 31 Wavelength band demultiplexer 32,33 Wavelength band conversion section 34<K×K> WSS (Specific WSS) 35,36 Wavelength band conversion section 37 Wavelength band multiplexing section 61 <1×P>WSS (1st WSS) 62a~62f Wavelength band conversion section 63<P×1> WSS (2nd WSS) #1~#j Wavelength band switching processing unit #1A~#jA Wavelength band conversion section

Claims

1. A wavelength cross-connect device, comprising: a plurality of input-side WSSs (Wavelength Selective Switches) for each of a plurality of optical transmission paths each composed of one or a plurality of optical fibers, which branch and output a wavelength multiplexed signal light, in which optical signals in the S-band, C-band, and L-band wavelength bands transmitted in multiband are multiplexed, into a predetermined number of signals; a plurality of wavelength band switching processing units that convert a wavelength band of a predetermined wavelength multiplexed signal light among the wavelength multiplexed signal light branched for each of the input WSSs into a different wavelength band; a plurality of output side WSSs mesh-connected to the input side WSS so that, of the wavelength multiplexed signal light branched for each input side WSS, the wavelength multiplexed signal light converted into the wavelength band is input and the wavelength multiplexed signal light without conversion is directly input; A wavelength cross-connect device comprising:

2. A wavelength cross-connect device, comprising: a plurality of input-side WSSs (Wavelength Selective Switches) for each of a plurality of optical transmission paths each composed of one or a plurality of optical fibers, which branch a wavelength-multiplexed signal light, in which optical signals of different wavelength bands transmitted in a multiband are multiplexed, into a predetermined number and output the branched signal light; a plurality of wavelength band switching processing units that convert a wavelength band of a predetermined wavelength multiplexed signal light among the wavelength multiplexed signal light branched for each of the input WSSs into a different wavelength band; a plurality of output WSSs mesh-connected to the input WSS so that, of the wavelength multiplexed signal light branched for each input WSS, the wavelength multiplexed signal light converted into the wavelength band is input, and unconverted wavelength multiplexed signal light is directly input; The wavelength band switching processing unit includes: a wavelength band demultiplexing unit that demultiplexes and outputs optical signals of different wavelength bands multiplexed into the wavelength multiplexed signal light from the input side WSS; an input side conversion unit that converts optical signals of wavelength bands other than a predetermined specific wavelength band, among the demultiplexed optical signals of different wavelength bands, into optical signals of the specific wavelength band; A specific WSS that has the same number of input ports and output ports as the number of the demultiplexed wavelengths, is capable of processing only the specific wavelength band, and outputs from the output port the specific wavelength band converted by the input side conversion unit input from the input port, or a specific wavelength band within the demultiplexed different wavelength band, so as to convert it into a predetermined wavelength band; an output side conversion unit that converts an optical signal of a specific wavelength band outputted from the output port into an optical signal of a predetermined wavelength band; a wavelength band multiplexing unit that multiplexes the optical signals of different wavelength bands from the output side conversion unit, converts them into wavelength multiplexed signal light, and outputs the multiplexed signal light to the output side WSS. A wavelength cross-connect device comprising:

3. A wavelength cross-connect device, comprising: a plurality of input-side WSSs (Wavelength Selective Switches) for each of a plurality of optical transmission paths each composed of one or a plurality of optical fibers, which branch a wavelength-multiplexed signal light, in which optical signals of different wavelength bands transmitted in a multiband are multiplexed, into a predetermined number and output the branched signal light; a plurality of wavelength band switching processing units that convert a wavelength band of a predetermined wavelength multiplexed signal light among the wavelength multiplexed signal light branched for each of the input WSSs into a different wavelength band; a plurality of output WSSs mesh-connected to the input WSS so that, of the wavelength multiplexed signal light branched for each input WSS, the wavelength multiplexed signal light converted into the wavelength band is input, and unconverted wavelength multiplexed signal light is directly input; The wavelength band switching processing unit includes: a first WSS that splits different wavelength bands multiplexed into the wavelength multiplexed signal light from the input WSS into a predetermined number of optical signals of the same wavelength band; a wavelength band converter unit, the number of which is equal to the number of the branches, for converting an optical signal of a wavelength band branched by the first WSS into an optical signal of a different wavelength band; a second WSS that multiplexes the optical signals of the respective wavelength bands converted by the wavelength band conversion unit to convert the optical signals into wavelength multiplexed signal light and outputs the multiplexed signal light to the output WSS. A wavelength cross-connect device comprising:

4. The input WSS performs a process of splitting the wavelength multiplexed signal light for each optical transmission line into optical signals of any one of the wavelength bands, and outputting the optical signal of any one of the split wavelength bands from any one of the output ports; A wavelength band conversion unit is provided to convert an optical signal of one wavelength band outputted from one output port of the input WSS into a different wavelength band instead of the wavelength band switching processing unit.

2. The wavelength cross-connect device according to claim 1,

5. The wavelength band conversion unit is The wavelength of an optical signal in one wavelength band output from one output port of the input WSS is shifted to a longer or shorter wavelength side to convert it into a wavelength in a different wavelength band.

5. The wavelength cross-connect device according to claim 4.

6. A wavelength cross-connect method using a wavelength cross-connect device, comprising: The wavelength cross-connect device comprises: a step of branching a wavelength-multiplexed signal light, in which optical signals in the S-band, C-band, and L-band wavelength bands transmitted in multiband are multiplexed, into a predetermined number of wavelengths and outputting the branched signal light for each of a plurality of optical transmission paths each composed of one or a plurality of optical fibers; converting a wavelength band of a predetermined wavelength multiplexed signal light among the branched wavelength multiplexed signal light into a different wavelength band; a step of changing a route of the wavelength multiplexed signal light converted into the predetermined wavelength band and the unconverted wavelength multiplexed signal light; A wavelength cross-connect method comprising:

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