Wavelength cross-connect device and wavelength cross-connect method

Abstract

This wavelength cross-connect device (1) comprises a wavelength band switching unit (10) and a WXC unit (20). In the wavelength band switching unit (10), each input side WSS branches off into a predetermined number of branches, and wavelength band switching processing units (#1-#j) convert the wavelength band of each of the predetermined number of branched wavelength multiplexed signal lights and output the converted signal lights. The WXC unit (20) includes: a plurality of <1×N> WSSs (21a to 21m) for branching and outputting multiplexed signal lights of each wavelength from the wavelength band switching unit (10); and a plurality of <N×1> WSSs 22a to 22m mesh-connected to the <1×N> WSSs (21a to 21m) in order to change the route of each wavelength multiplexed signal light.

Description

Technical Field

[0001] The present invention relates to a wavelength cross-connect device and a wavelength cross-connect method used for multi-band transmission in which wavelength-division multiplexed signal light obtained by multiplexing optical signals in different wavelength bands is transmitted through an optical fiber.

Background Art

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

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

[0004] However, each wavelength band is, in order from the short-wavelength side, the S band of 1460 nm to 1530 nm, the C band of 1530 nm to 1565 nm, and the L band of 1565 nm to 1625 nm. Each optical signal in the S band, C band, and L band is assigned to the S band, C band, and L band of the optical fiber as a path during transmission.

[0005] Each of the above demultiplexed optical signals in the S-band, C-band, and L-band (each wavelength band) is input to each WXC (Wavelength Cross Connect) unit provided for each wavelength band. In each WXC, each wavelength band's optical signal undergoes processing such as attenuation adjustment using a WSS for each wavelength band arranged on the input side of the WXC, and is input to the WSS for each wavelength band on the output side that is mesh-connected to the input-side WSS. The input optical signals in the S-band, C-band, and L-band are multiplexed by the output-side WSS, and the wavelength-division multiplexed signal light resulting from this multiplexing is multi-band transmitted to M output-side optical paths.

[0006] As a conventional technique related to this type of wavelength cross-connect device, there is one described in Non-Patent Document 1.

Prior Art Documents

Non-Patent Documents

[0007]

Non-Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0008] However, in the above-described conventional wavelength cross-connect device, in the configuration of each WXC in the S-band, C-band, and L-band, due to differences in optical characteristics caused by differences in each wavelength band, there are deviations in the transmission performance of the optical signals in the S-band, C-band, and L-band. For example, wavelength band dependencies occur in the transmission band and optical loss, which are the specifications of the WSS and optical amplifier, and these wavelength band dependencies cause deviations in the transmission performance of optical signals between 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 view of such circumstances, and an object thereof is to suppress differences in the transmission performance of optical signals in different wavelength bands in an optical network and improve the utilization efficiency of each wavelength band in the optical network.

Means for Solving the Problems

[0010] In order to solve the above problems, the present invention is a wavelength cross-connect device, 1 For each of a plurality of optical transmission paths composed of one or more optical fibers, each wavelength-division multiplexed signal light obtained by multiplexing optical signals in different wavelength bands transmitted in a multi-band manner is branched into a predetermined number, and wavelength band conversion is performed for each of the branched predetermined number of wavelength-division multiplexed signal lights and output, a wavelength band switching unit, Before A plurality of first input-side WSSs that branch and output each of the wavelength-division multiplexed signal lights output from the wavelength band switching unit, and a plurality of first output-side WSSs mesh-connected to the first input-side WSSs, and the wavelength-division multiplexed signal light branched by the first input-side WSSs is input to the first output-side WSSs, and after performing a path change, it is output to an output transmission path, a WXC (Wavelength Cross Connect) unit and Comprising is in a state where the wavelength band switching unit includes a plurality of second input side WSSs that branch and output each of the wavelength division multiplexed signal lights for each of the optical transmission paths to a predetermined number, a plurality of wavelength band switching processing units that output wavelength division multiplexed signal lights in which the wavelength bands of the optical signals multiplexed in the wavelength division multiplexed signal lights branched and output by the second input side WSSs are converted into different wavelength bands, and a second output side WSS that outputs the wavelength division multiplexed signal lights output from the plurality of wavelength band switching processing units and the wavelength division multiplexed signal lights directly output from the second input side WSS to the first input side WSS of the WXC unit while selecting one by one and includes Characterized by that.

Effects of the Invention

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

Brief Description of the Drawings

[0012]

Figure 1

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Embodiment for Carrying Out the Invention

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

[0014] The wavelength cross-connect device 1 shown in FIG. 1 includes a wavelength band switching unit 10 and a WXC unit 20.

[0015] The wavelength band switching unit 10 is connected for each of M input paths indicated by the symbol Mi, and M <1×Q> WSSs (Wavelength Selective Switches) 11a, 11b,..., 11m to which wavelength multiplexed signal lights 1a, 1b,..., 1m that have been multi-band transmitted for each input path are input, and each of the M <Q×1> WSSs 12a, 12b,..., 12m on the output side. Further, between the <1×Q> WSSs 11a to 11m on the input side and the <Q×1> WSSs 12a to 12m on the output side, M sets of wavelength band switching processing units #1 to #j, each set consisting of j units, are provided.

[0016] However, each of the M paths Mi is composed of one or a plurality of optical fibers. Also, in each of the wavelength multiplexed signal lights 1a to 1m that have been multi-band transmitted for each input path, as shown by 1a<S,C,L>, 1b<S,C,L>, 1m<S,C,L> in FIG. 1, it is assumed that optical signals in the S band, C band, and L band are multiplexed. Further, the <1×Q> WSSs 11a to 11m on the input side constitute the second input side WSS described in the claims. The <Q×1> WSSs 12a to 12m on the output side constitute the second output side WSS described in the claims.

[0017] The <1×Q> WSSs 11a to 11m on the input side have one input port and Q output ports (referred to as Q output ports), and the <Q×1> WSSs 12a to 12m on the output side have Q input ports (Q input ports) and one output port. However, it is assumed that Q = j + 1. Also, in this example, the output ports and input ports are numbered 1st, 2nd,... in order from the top in the figure.

[0018] The first output port among the Q output ports of the <1×Q> WSS 11a related to one input path is directly connected to the first input port among the Q input ports of the <Q×1> WSSs 12a to 12m on the output side. Between the second to Q-th output ports and the second to Q-th input ports, j wavelength band switching processing units #1 to #j (described later) are connected. Such a connection configuration is the same between the <1×Q> WSSs 11b to 11m on the input side related to other input paths and the <Q×1> WSSs 12b to 12m on the output side.

[0019] Since the <1×Q> WSSs 11a to 11m on the input side have the same function, the first <1×Q> WSS 11a will be described as a representative. The first <1×Q> WSS 11a divides the wavelength multiplexed signal light 1a transmitted in the multi-band (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 ports. Among the Q wavelength multiplexed signal lights 1a thus output, the first wavelength multiplexed signal light 1a is output to the first input port of the <Q×1> WSS 12a on the output side. The second to Q-th wavelength multiplexed signal lights 1a are input to the second to Q-th input ports of the <Q×1> WSS 12a after wavelength band conversion and the like are performed by the wavelength band switching processing units #1 to #j described later. However, the WSS has a function of performing Q-branching by outputting each optical signal of the wavelength multiplexed signal light input from the input port from an arbitrary output port, rather than a simple Q-branching by a coupler or the like.

[0020] The <Q×1> WSSs 12a to 12m on the output side have the same function, and have a processing function of sequentially selecting the multi-band wavelength multiplexed signal light input from the Q input ports and outputting it from one output port to the <1×N> WSSs 21a to 21m of the WXC unit 20.

[0021] <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 with the wavelength band switching processing unit #1 as a representative, it includes a wavelength band demultiplexing unit 31, a plurality of input-side wavelength band conversion units 32 and 33, a <K×K> WSS 34, a plurality of output-side wavelength band conversion units 35 and 36, and a wavelength band multiplexing unit 37.

[0022] K is the number of wavelength bands. In this example, K = 3 for the S band, C band, and L band. Note that the <K×K> WSS 34 constitutes the specific WSS described in the claims. Also, the input-side wavelength band conversion units 32 and 33 constitute the input-side conversion units described in the claims. The output-side wavelength band conversion units 35 and 36 constitute the output-side conversion units described in the claims.

[0023] The wavelength band demultiplexing unit 31 demultiplexes the wavelength multiplexed signal light in which the optical signals of the S band, C band, and L band input from the <Q×1> WSSs 12a to 12m (Fig. 1) of the wavelength band switching unit 10 are multiplexed, and outputs each of the demultiplexed optical signals of the S band, C band, and L band. However, it is assumed that the C band is one wavelength band (specific wavelength band) that the <K×K> WSS 34 can process. The <K×K> WSS 34 can only process the optical signals of the specific wavelength band (C band). Therefore, the demultiplexed optical signals of the C band are input to the <K×K> WSS 34 in their original state.

[0024] The input-side wavelength band conversion unit 32 of the <K×K> WSS 34 converts the optical signal of the S band into an optical signal of the C band and outputs it to the <K×K> WSS 34. The wavelength band conversion unit 33 converts the optical signal of the L band into an optical signal of the C band and outputs it to the <K×K> WSS 34.

[0025] The output-side wavelength band conversion unit 35 converts the optical signal of the C band into an optical signal of the S band and outputs it to the wavelength band multiplexing unit 37. The wavelength band conversion unit 36 converts the optical signal of the C band into an optical signal of the L band and outputs it to the wavelength band multiplexing unit 37.

[0026] The <K×K> WSS34 performs a process of converting the wavelength band of the optical signals multiplexed in the wavelength-division multiplexed signal lights 1a to 1m input from the optical transmission path Mi on the input side of the wavelength cross-connect device 1 (Fig. 1) into different wavelength bands.

[0027] This <K×K> WSS34 has the same number of input ports and output ports as the number of wavelength bands K = 3 of the optical signals multiplexed in the wavelength-division multiplexed signal light. In the <K×K> WSS34, the optical signals in the C band input from K = 3 input ports are output from K = 3 output ports connected to the wavelength band conversion units 35 and 36 or the wavelength band multiplexing unit 37 that perform conversion to a predetermined wavelength band.

[0028] For example, after the optical signals in the C band demultiplexed by the wavelength band demultiplexing unit 31 are input to the second input port of the <K×K> WSS34, they are input from the first output port to the wavelength band conversion unit 35, and are converted into optical signals in the S band by this wavelength band conversion unit 35. This example is a conversion process for converting the optical signals in the C band input from the input optical path Mi into optical signals in the S band and transmitting them to the optical transmission path Mo (Fig. 1) on the output side.

[0029] The wavelength band multiplexing unit 37 multiplexes the optical signals in the S band, C band, and L band, and outputs them to the second input port of the <Q×1> WSSs 12a to 12m on the output side shown in Fig. 1.

[0030] Next, the WXC unit 20 shown in Fig. 1 includes M <1×N> WSSs 21a, 21b,..., 21m connected to the output ports of the M <Q×1> WSSs 12a to 12m of the wavelength band switching unit 10, and M <N×1> WSSs 22a, 22b,..., 22m on the output side fully mesh-connected (described later) to the M <1×N> WSSs 21a to 21m on the input side. However, N and M have a magnitude relationship of M > N, and N = M - 1. The M <1×N> WSSs 21a to 21m on the input side constitute the first input side WSS described in the claims. The M <N×1> WSSs 22a to 22m on the output side constitute the first output side WSS described in the claims.

[0031] The output ports of the <N×1> WSSs 22a to 22m on the output side are connected to M output paths indicated by the code Mo that outputs wavelength-division multiplexed signal light. Also, the <1×N> WSSs 21a to 21m on the input side may be optical couplers such as a 1×N optical fiber coupler.

[0032] The full mesh connection is as follows. That is, in the <1×N> WSSs 21a to 21m on the input side, the N output ports (N-output ports) of the first WSS 21a are connected to the N-input ports of the second to M-th WSSs 22b to 22m excluding the first one on the output side. In this way, the N output ports of each of the <1×N> WSSs 21a to 21m are connected to the N-input ports of each of the <N×1> WSSs 22a to 22m excluding the output-side WSS in the same path as the input-side WSS. By this connection, a path is configured in which the wavelength-division multiplexed signal light output from the N output ports of the <1×N> WSSs 21a to 21m is changed in path.

[0033] The <1×N> WSSs 21a to 21m on the input side have the same function and are provided with a function capable of collectively switching wavelength selection for a multi-band (wavelength bands of S-band, C-band, and L-band). Representing the first input-side WSS 21a, the WSS 21a branches the wavelength-division multiplexed signal light 1a input from the 1-input port and outputs the branched wavelength-division multiplexed signal light 1a from the N output ports.

[0034] The <N×1> WSSs 22a to 22m on the output side have the same function and are provided with a function capable of collectively switching wavelength selection for a multi-band. Representing the first output-side WSS 22a, the WSS 22a sequentially selects each wavelength-division multiplexed signal light input from the N-input ports and outputs it from the 1-output port to 1 output path.

[0035] <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. 3.

[0036] In step S1 shown in FIG. 3, the wavelength-division multiplexed signal lights 1a to 1m that have been multi-band transmitted for each of the M input channels shown in FIG. 1 are input to the single input ports of each of the M <1×Q> WSSs 11a to 11m of the wavelength band switching unit 10. Note that for each of the wavelength-division multiplexed signal lights 1a to 1m, the optical signals in the S band, C band, and L band are multiplexed.

[0037] In step S2, each of the <1×Q> WSSs 11a to 11m divides each wavelength-division multiplexed signal light 1a to 1m into Q branches, directly outputs it to the first input ports of the <Q×1> WSSs 12a to 12m on the output side, and outputs it to the wavelength band switching processing units #1 to #j.

[0038] In step S3, the wavelength band switching processing units #1 to #j demultiplex the input wavelength-division multiplexed signal lights in the S band, C band, and L band in the wavelength band demultiplexing unit 31 shown in FIG. 2, and output each of the demultiplexed optical signals in the S band, C band, and L band. At this time, the optical signal in the C band is input to the <K×K> WSS 34 in its original state. The optical signal in the S band is output to the wavelength band conversion unit 32, and the optical signal in the L band is output to the wavelength band conversion unit 33.

[0039] In step S4, the wavelength band conversion unit 32 converts the optical signal in the S band into an optical signal in the C band and outputs it to the <K×K> WSS 34. The wavelength band conversion unit 33 converts the optical signal in the L band into an optical signal in the C band and outputs it to the <K×K> WSS 34. The optical signal in the C band is output to the <K×K> WSS 34 without conversion.

[0040] In step S5, the <K×K> WSS 34 outputs the optical signal in the C band input from the K (3) input ports from the K output ports required for wavelength band conversion. For example, the optical signal in the C band input from the second input port of the <K×K> WSS 34 is output from the first output port to the wavelength band conversion unit 35.

[0041] In step S6, the wavelength band conversion unit 35 converts the optical signal in the C band into an optical signal in the S band and outputs it to the wavelength band multiplexing unit 37. The wavelength band conversion unit 36 converts the optical signal in the C band into an optical signal in the L band and outputs it to the wavelength band multiplexing unit 37.

[0042] In step S7, the wavelength-band multiplexer 37 multiplexes the optical signals in the S band, C band, and L band into a wavelength-division multiplexed signal light, and outputs the multiplexed signal light to the second to Q-th input ports for each of the <Q×1> WSSs 12a to 12m shown in FIG. 1.

[0043] In step S8, each of the <Q×1> WSSs 12a to 12m sequentially selects the wavelength-division multiplexed signal light in the S band, C band, and L band input from the Q input ports, and outputs the selected signal light to the first input port of each of the <1×N> WSSs 21a to 21m in the WXC unit 20 from the output ports.

[0044] In step S9, the <1×N> WSSs 21a to 21m split the wavelength-division multiplexed signal light 1a input from the first input port into N branches, and output the N-branched wavelength-division multiplexed signal light from the N output ports to the N input ports of the <N×1> WSSs 22a to 22m. For example, for the first WSS21a, the wavelength-division multiplexed signal light is output from these N output ports to the N input ports of the second to M-th WSSs 22b to 22m excluding the first one on the output side. By such output, the wavelength-division multiplexed signal light is rerouted.

[0045] In step S10, each of the <N×1> WSSs 22a to 22m on the output side sequentially selects the wavelength-division multiplexed signal light in the S band, C band, and L band input from the N input ports, and outputs the selected signal light from the first output port to the first output path.

[0046] <Effect of Embodiment> The effect of the wavelength cross-connect device 1 according to the embodiment of the present invention will be described.

[0047] (1a) The wavelength cross-connect device 1 includes a wavelength-band switching unit 10 and a WXC unit 20. The wavelength-band switching unit 10 branches each of the wavelength-division multiplexed signal lights obtained by multiplexing the optical signals in different wavelength bands (S band, C band, and L band) transmitted in a multi-band manner for each of the M optical transmission paths composed of one or a plurality of optical fibers into a predetermined number, and performs wavelength-band conversion for each of the branched wavelength-division multiplexed signal lights having the predetermined number, and outputs the converted signal lights.

[0048] The WXC unit 20 includes <1×N> WSSs 21a to 21m as a plurality of first input-side WSSs that branch and output each wavelength-division multiplexed signal light output from the wavelength band switching unit 10, and <N×1> WSSs 22a to 22m as a plurality of second output-side WSSs mesh-connected to the <1×N> WSSs 21a to 21m. The wavelength-division multiplexed signal light branched by the <1×N> WSSs 21a to 21m is input to the <N×1> WSSs 22a to 22m, and after the path is changed, it is output to the output transmission path Mo.

[0049] According to this configuration, the wavelength cross-connect device 1 can change the wavelength band of the wavelength-division multiplexed signal light in which each optical signal of different wavelength bands transmitted in a multi-band is multiplexed by the wavelength band switching unit, and then change the path in the WXC unit and output it to the output-side path.

[0050] Therefore, in the multi-band transmission system 40 (FIG. 4) in which a plurality of nodes to which the wavelength cross-connect device is applied are link-connected, the wavelength band can be converted in units of links and wavelengths described later. By this conversion, for example, the wavelength (for example, wavelength C1 in the C band) of the free wavelength band of the optical transmission path between nodes 40a and 40b can be converted and used by the wavelength cross-connect device 1 on the front side of the section between the nodes 40a and 40b. Since the wavelength of the wavelength free section can be set to be usable in this way, the usage capacity of the network can be improved. That is, the utilization efficiency of the network of the multi-band transmission system can be improved.

[0051] The multi-band transmission system (also referred to as a system) 40 shown in FIG. 4 is configured such that each node 40a, 40b, 40c, 40d, 40e, 40f as a communication device including the wavelength cross-connect device 1 is connected in a ring shape by optical transmission paths 41a, 41b, 41c, 41d, 41e, 41f made of optical fibers.

[0052] The above-mentioned link unit is a unit of the optical transmission path 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 two adjacent node sections.

[0053] In the prior art, for example, when multi-band transmitting optical signals in different wavelength bands in multiple paths via optical transmission paths 41a, 41b, and 41c between nodes 40a - 40b - 40c - 40d with node 40a as the starting point and node 40d as the ending point, the transmission was limited to one wavelength band in one path. Note that the section between nodes 40a - 40b - 40c - 40d is also referred to as between nodes 40a...40d.

[0054] For example, when multi-band transmitting optical signals in the S band, C band, and L band between nodes 40a...40d, path 1 through optical transmission paths 41a to 41c only transmitted optical signals in the S band, path 2 only transmitted optical signals in the C band, and path 3 only transmitted optical signals in the L band.

[0055] Here, in multi-band transmission, there is a characteristic that power transitions from an optical signal with a short wavelength to an optical signal with a long wavelength. Therefore, in the above example, the transmission of the optical signal in the S band of path 1 has poor transmission performance, the transmission of the optical signal in the C band of path 2 has normal transmission performance, and the transmission of the optical signal in the L band of path 3 often has good transmission performance. Thus, there are deviations in transmission performance among paths 1, 2, and 3.

[0056] The transmission performance is also determined depending on parameters such as the transmission band and loss amount as the performance of devices (optical products) such as optical fibers, and stimulated Raman scattering (SRS), which is one of the nonlinear optical effects. The above parameters have strong band dependence. Since the transmission performance depends on the wavelength band used as described above, deviations occur between different wavelength bands.

[0057] In contrast, in the present embodiment, the wavelength cross-connect device 1 can change the wavelength band for each section (link unit) between each node 40a...40d.

[0058] For example, as shown in FIG. 5, in path 1 between nodes 40a - 40b - 40c - 40d, an optical signal in the S band is transmitted in the first section (between nodes 40a - 40b), an optical signal in the C band is transmitted in the second section (between nodes 40b - 40c), and an optical signal in the L band is transmitted in the third section (between nodes 40c - 40d). In path 2, an optical signal in the C band is transmitted in the first section, an optical signal in the L band is transmitted in the second section, and an optical signal in the S band is transmitted in the third section. In path 3, an optical signal in the L band is transmitted in the first section, an optical signal in the S band is transmitted in the second section, and an optical signal in the C band is transmitted in the third section.

[0059] When optical signals in different wavelength bands are transmitted for each of paths 1, 2, and 3 in each section in this way, the transmission performance of different wavelength bands for each of paths 1, 2, and 3 in each section is averaged. By this averaging, the deviation in transmission performance between paths 1 to 3 is suppressed. By suppressing this deviation, the utilization efficiency of the network of the multi - band transmission system can be improved.

[0060] Next, the effect of being able to convert the wavelength band in wavelength units will be described. As shown in FIG. 6, it is assumed that the S band of the optical signal is composed of wavelengths S1, S2, S3, the C band is composed of wavelengths C1, C2, C3, and the L band is composed of wavelengths L1, L2, L3.

[0061] In the prior art, in one path for the entire section, it was limited to the setting in one wavelength band. However, in this embodiment, with the wavelength cross - connect device 1, any wavelength in a different wavelength band can be set for each of paths 1, 2, and 3 for each section of nodes 40a - 40b - 40c - 40d. For example, wavelength S1 in the S band is set for path 1 of the optical transmission line 41a in the section between nodes 40a - 40b, wavelength C1 in the C band is set for path 2 of the optical transmission line 41b in the section between nodes 40b - 40c, and wavelength L1 in the L band is set for path 3 of the optical transmission line 41c in the section between nodes 40c - 40d, and an optical signal can be transmitted with the set wavelengths S1, C1, and L1.

[0062] In the case of this embodiment where the wavelength band can be converted in wavelength units in this way, the wavelength continuity constraint of the prior art can be avoided. The wavelength continuity constraint means the necessity of continuous transmission at the same wavelength within one wavelength band in one path between nodes 40a... 40d.

[0063] For example, as shown in FIG. 7, it is assumed that wavelengths S1, S2, S3 in the S band, wavelengths C1, C2, C3 in the C band, and wavelengths L1, L2, L3 in the L band are set between each of the nodes 40a... 40d except for the sections indicated by the five elliptical dashed frames. In this case, in the prior art, due to the wavelength continuity constraint, in the wavelength free section indicated by the elliptical dashed frame, the same wavelength on the same path collides, so the corresponding wavelength cannot be used. For example, in the wavelength free section in the C band between nodes 40a - 40b indicated by the elliptical dashed frame, since the wavelength C2 has already been set between nodes 40b - 40d, the wavelength C2 of the same wavelength that collides with this cannot be set.

[0064] However, in this embodiment, since the wavelength cross - connect device 1 can convert the wavelength band in wavelength units, for example, the wavelength C2 shown within the elliptical dashed frame in the C band between nodes 40a - 40b can be set. Further, the wavelength S2 shown within the elliptical dashed frame in the S band between nodes 40b - 40c can be set, and the wavelength L2 shown within the elliptical dashed frame in the L band between nodes 40c - 40d can be set. In this case, the optical signal can be transmitted using the wavelength C2 in the wavelength band C between nodes 40a - 40b, the wavelength S2 in the wavelength band S between nodes 40b - 40c, and the wavelength L2 in the wavelength band L between nodes 40c - 40d.

[0065] In this way, by using the free wavelengths indicated by the elliptical dashed frame and being able to transmit the optical signal while avoiding wavelength collision, the usage capacity of the network can be improved. That is, the utilization efficiency of the network of the multi - band transmission system can be improved.

[0066] Furthermore, by such conversion in wavelength units of the wavelength band, the capacity constraint due to inter - band induced Raman scattering occurring in the S band can also be avoided.

[0067] <Path setting example 1> Here, Example 1 of path setting will be described with reference to FIG. 8. 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. A plurality of arrows W1 indicate wavelength band switching points.

[0068] The path setting device 55 manages the usage status of wavelengths between the nodes 40a to 40d. For example, when an order to newly set a path between the nodes 40a to 40d is added by the external terminal device 56, since a path cannot be set between the nodes 40a to 40d using the same wavelength, the path setting device 55 checks the available state of the wavelength.

[0069] The path setting device 55 gives the instructions described in the following (1) to (4) according to the confirmation of the available state of the wavelength. (1) The path setting device 55 instructs the node 40a to transmit the wavelength C2 in the C band to the node 40b as indicated by the arrow Y11 in order to set an optical path on the optical transmission line 41a. (2) The path setting device 55 instructs the node 40b to switch the C band of the optical signal of the input wavelength C2 to the S band and convert it into an optical signal of wavelength S2 as indicated by the arrow Y12 in order to set an optical path on the optical transmission line 41b, and then transmit it to the node 40c. (3) The path setting device 55 instructs the node 40c to switch the S band of the optical signal of the input wavelength S2 to the L band and convert it into an optical signal of wavelength L2 as indicated by the arrow Y13 in order to set an optical path on the optical transmission line 41c, and then transmit it to the node 40d. (4) The path setting device 55 may instruct the node 40d to return to the wavelength S2 in the S band. This is executed when the available wavelength bands are determined at the start point and end point of the path.

[0070] Next, as shown in FIG. 9, in the S-band, C-band, and L-band, when inter-band induced Raman scattering does not occur, the optical signal-to-noise ratios {SNR (Signal-to-Noise Ratio) [dB] on the vertical axis} of the S-band, C-band, and L-band are substantially the same as shown by the broken line 51.

[0071] On the other hand, when inter-band induced Raman scattering occurs, the SNR of the S-band, C-band, and L-band decreases as the frequency of the wavelength band increases, in other words, as the wavelength of the wavelength band becomes shorter, as shown by the solid line 52. The SNR is worst in the S-band. For this reason, as shown by the broken-line horizontal bar with reference numeral 54 in FIG. 10, optical signal transmission through the S-band could not be performed between nodes 40a - 40b - 40c - 40d.

[0072] However, in this embodiment, since the wavelength cross-connect device 1 can convert the wavelength band in wavelength units, the wavelengths of different wavelength bands may be set in the wavelength free section shown by the elliptical broken-line frame as follows. That is, wavelength C3 may be set between nodes 40a - 40b, wavelength S3 may be set between nodes 40b - 40c, and wavelength L3 may be set between nodes 40c - 40d. With this setting, wavelength C3 of the wavelength band C is used between nodes 40a - 40b, wavelength S3 of the wavelength band S is used between nodes 40b - 40c, and wavelength L3 of the wavelength band L is used between nodes 40c - 40d, and optical signals can be transmitted while mitigating the influence of inter-band induced Raman scattering.

[0073] <Path Setting Example 2> Here, Path Setting Example 2 will be described with reference to FIG. 11. However, as in the case shown in FIG. 8 above, a path setting device 55 to which an external terminal device 56 is connected is connected to each of the nodes 40a to 40d.

[0074] The path setting device 55 manages the usage status of wavelengths among nodes 40a...40d. For example, when an order to newly set a path among nodes 40a...40d is added by the external terminal device 56, the path setting device 55 checks the availability status of wavelengths. In the case of the example in FIG. 11, it is possible to set a path among nodes 40a to 40d using wavelength S3. However, as a setting condition, for example, when it is stipulated that wavelength S3 can be set for up to two consecutive links, a path cannot be set for the optical transmission paths 41a, 41b, 41c using wavelength S3.

[0075] Therefore, the path setting device 55 gives the instructions described in the following (1) to (4) according to the confirmation of the availability status of the above wavelengths. (1) The path setting device 55 instructs node 40a to transmit an optical signal of wavelength S3 in the S band to node 40b as indicated by arrow Y21 in order to set an optical path for the optical transmission path 41a. (2) The path setting device 55 instructs node 40b to directly transmit the input optical signal of wavelength S3 as it is to node 40c as indicated by arrow Y21 in order to set an optical path for the optical transmission path 41b. (3) The path setting device 55 instructs 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, and transmit it to node 40d as indicated by arrow Y22 in order to set an optical path for the optical transmission path 41c. (4) The path setting device 55 may instruct node 40d to return to wavelength S2 in the S band. This is executed when the available wavelength bands are determined at the start point and end point of the path.

[0076] As described above, since the inter-band stimulated Raman scattering can be avoided and an optical signal can be transmitted among nodes 40a...40d, the capacity constraint due to the inter-band stimulated Raman scattering can also be avoided. Therefore, the usage capacity of the network in the multi-band transmission system can be improved, and the utilization efficiency of the network can be improved.

[0077] That is, generally, it decreases from a state where the network efficiency is 100% due to wavelength continuity constraints, and further decreases due to capacity constraints caused by the influence of inter-band induced Raman scattering. However, according to the wavelength cross-connect device 1 of the present embodiment, the decrease in its network efficiency can be suppressed.

[0078] (2a) The wavelength band switching unit 10 includes <1×Q> WSSs 11a to 11m as a plurality (M) of second input-side WSSs that branch and output each of the wavelength-division multiplexed signal lights 1a to 1m for each optical transmission line to a predetermined number. Further, it includes a plurality (M) of wavelength band switching processing units #1 to #j that output wavelength-division multiplexed signal lights in which the wavelength bands of the optical signals multiplexed in the wavelength-division multiplexed signal lights branched and output by the <1×Q> WSSs 11a to 11m are converted into different wavelength bands. Furthermore, it is configured to include <Q×1> WSSs 12a to 12m as a second output-side WSS that outputs the wavelength-division multiplexed signal lights output from the wavelength band switching processing units #1 to #j and the wavelength-division multiplexed signal lights directly output from the <1×Q> WSSs 11a to 11m to the <1×N> WSSs 21a to 21m of the WXC unit 20 while selecting them one by one.

[0079] According to this configuration, when the traffic of the wavelength-division multiplexed signal light transmitted in a multi-band increases and it is desired to increase the number of wavelength band switches in the wavelength band switching unit 10, it can be easily increased by increasing it in units of the wavelength band switching processing unit (for example, the wavelength band switching processing unit #1).

[0080] (3a) The wavelength band switching processing units #1 to #j are configured to include a wavelength band demultiplexing unit 31, wavelength band conversion units 32 and 33 as input-side conversion units, a <K×K> WSS 34 as a specific WSS, wavelength band conversion units 35 and 36 as output-side conversion units, and a wavelength band multiplexing unit 37.

[0081] The wavelength band demultiplexing unit 31 demultiplexes and outputs optical signals in different wavelength bands multiplexed in the wavelength-division multiplexed signal light from one output port of each of the input-side <1×Q> WSSs 11a to 11m.

[0082] The wavelength band conversion units 32 and 33 as the input-side conversion units convert optical signals in wavelength bands other than a predetermined specific wavelength band among the optical signals in different wavelength bands demultiplexed by the wavelength band demultiplexing unit 31 into optical signals in the specific wavelength band.

[0083] <K×K>WSS 34 has the same number of input ports and output ports as the number of demultiplexing at the wavelength band demultiplexing unit 31, can process only the specific wavelength band, and outputs from the output port so as to convert the specific wavelength band converted by the wavelength band conversion units 32 and 33 input from the input port, or the specific wavelength band within the different wavelength bands demultiplexed above, into a predetermined wavelength band.

[0084] The wavelength band conversion units 35 and 36 as the output-side conversion units convert the optical signals in the specific wavelength band output from the output port into optical signals in a predetermined wavelength band. The wavelength band multiplexing unit 37 multiplexes each optical signal in a different wavelength band from the wavelength band conversion units 35 and 36 to convert it into wavelength-division multiplexed signal light, and outputs it to each of <Q×1> WSSs 12a to 12m on the output side.

[0085] According to this configuration, by the <K×K> WSS 34, the specific wavelength band converted by the wavelength band conversion units 32 and 33 on the input side, or the specific wavelength band within the different wavelength bands demultiplexed by the wavelength band demultiplexing unit 31, is output from the output port so as to be converted into a predetermined wavelength band. Thus, since each optical signal in a different wavelength band can be converted into an optical signal in a predetermined wavelength band by one <K×K> WSS 34, the wavelength band switching processing units #1 to #j can be miniaturized.

[0086] <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 by representing the wavelength band switching processing unit #1 in FIG. 12 in addition to the configuration shown in FIG. 2.

[0087] The wavelength band switching processing unit #1 shown in Fig. 12 is configured to include a <1×P> WSS 61, P wavelength band conversion units 62a, 62b, 62c, 62d, 62e, 62f, and a <P×1> WSS 63. P is the same number as the number of output ports of the <1×P> WSS 61, the number of input ports of the <P×1> WSS 63, and the number of wavelength band conversion units 62a to 62f.

[0088] However, either one of the <1×P> WSS 61 and the <P×1> WSS 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 described in the claims. The <P×1> WSS 63 constitutes the second WSS described in the claims.

[0089] <1×P> WSS 61 branches P each of the optical signals in the S band, C band, and L band of different wavelength bands multiplexed in the wavelength multiplexed signal light input from the <1×Q> WSS 11a (Fig. 1). This P - branch is performed while including a predetermined number of optical signals in the same wavelength band. In this example, the optical signals in the S band, C band, and L band are P - branched while including two each as follows. That is, the optical signals in the S band are output to the wavelength band conversion units 62a and 62b, the optical signals in the C band are output to the wavelength band conversion units 62c and 62d, and the optical signals in the L band are output to the wavelength band conversion units 62e and 62d.

[0090] The wavelength band conversion unit 62a converts the S band into an optical signal in the C band, and the wavelength band conversion unit 62b converts the S band into an optical signal in the L band and outputs it to the input port of the <P×1> WSS 63. The wavelength band conversion unit 62c converts the C band into an optical signal in the S band, and the wavelength band conversion unit 62d converts the C band into an optical signal in the L band and outputs it to the input port of the <P×1> WSS 63. The wavelength band conversion unit 62e converts the L band into an optical signal in the S band, and the wavelength band conversion unit 62f converts the L band into an optical signal in the C band and outputs it to the input port of the <P×1> WSS 63.

[0091] <P×1> WSS 63 multiplexes two each of the S band, C band, and L band input to the P input ports, and outputs the wavelength multiplexed signal light to the <Q×1> WSS 12a shown in Fig. 1.

[0092] According to this configuration, with the wavelength band switching processing unit #1 having a simple configuration, different wavelength bands multiplexed on the wavelength division multiplexed signal light for each input transmission line can be converted into optical signals of other different wavelength bands.

[0093] In addition, in the wavelength band switching processing unit #1 shown in FIG. 2 or FIG. 12, a WSS that can handle at least two or more wavelength bands may be used. Also, for the input side WSSs 11a to 11m and the output side WSSs 12a to 12m of the wavelength band switching unit 10 shown in FIG. 1, and the input side WSSs 21a to 21m and the output side WSSs 22a to 22m of the WXC unit 20, a WSS that can handle at least two or more wavelength bands may also be used. For example, instead of the WSS 34 that can process the S band, C band, and L band shown in FIG. 2, a set may be configured with a WSS for the S band and a WSS for the C band and L band. Also, when using the E band, S band, C band, and L band, it may be configured to include a WSS for the E band and S band and a WSS for the C band and L band. That is, a configuration that can process the four wavelength bands in half may be used.

[0094] <Modification Example 1 of the Embodiment> FIG. 13 is a block diagram showing the configuration of a wavelength cross-connect device according to Modification Example 1 of the embodiment of the present invention.

[0095] The difference between the wavelength cross-connect device 1A of Modification Example 1 shown in FIG. 13 and the wavelength cross-connect device 1 (FIG. 1) of the above embodiment is that, instead of the <1×Q> WSSs 11a to 11m on the input side of the wavelength band switching unit 10 and the wavelength band switching processing units #1 to #j (FIG. 1), it is provided with the <1×Q> WSSs 11aA to 11mA on the input side of the wavelength band switching unit 10A and the wavelength conversion units #1A to #jA.

[0096] Since the <1×Q> WSSs 11aA to 11mA on the input side have the same function, the first <1×Q> WSS 11aA will be described as a representative. The first <1×Q> WSS 11aA Q-branches the wavelength-division multiplexed signal light 1a transmitted in the multi-band (wavelength bands of S-band, C-band, and L-band) into optical signals in any of the S-band, C-band, and L-band, and outputs the optical signal in any one of the wavelength bands among the Q-branched signals from any one of the Q output ports. For example, an optical signal in the L-band is output from the first output port of the Q output ports, an optical signal in the S-band is output from the second output port, and an optical signal in the C-band is output from the j-th output port.

[0097] The wavelength band conversion units #1A to #jA perform a process of converting the wavelength bands (S-band, C-band, and L-band) output from the input-side <1×Q> WSSs 11aA to 11mA into different wavelength bands. For example, the wavelength band conversion unit #1A connected to the output port of the <1×Q> WSS 11aA is set to convert the S-band of the wavelength band into the C-band, and the wavelength band conversion unit #jA is set to convert the C-band into the L-band.

[0098] The optical signal in the L-band output from the first output port of the <1×Q> WSS 11aA is output to the first input port of the output-side <Q×1> WSS 12a. The optical signal in the S-band output from the second output port is output to the wavelength band conversion unit #1A and is converted into an optical signal in the C-band. The optical signal in the C-band output from the j-th output port is output to the wavelength band conversion unit #jA and is converted into an optical signal in the L-band.

[0099] Also in the wavelength cross-connect device 1A of this Modification 1, the same effects as those of the above-described embodiment can be obtained. Further, since the wavelength band conversion units #1A to #jA of Modification 1 can have a simpler and smaller configuration than the wavelength band switching processing units #1 to #j of the embodiment, the wavelength cross-connect device 1A can be downsized accordingly.

[0100] In addition, the wavelength band conversion units #1A to #jA may shift the wavelength (for example, the wavelength S1 in the S-band) of the wavelength band of the wavelength-division multiplexed signal lights 1a to 1m to the longer wavelength side or the shorter wavelength side to convert it into a wavelength (the wavelength C2 in the C-band) in a different wavelength band.

[0101] This shift is performed by setting as follows. For example, in wavelength band conversion unit #1A connected to the input side WSS11aA (<1×Q>WSS11aA), as shown by arrow Y1 in FIG. 14, the wavelength S1 in the S band of the optical signal is shifted to the longer wavelength side by a shift amount of <+3> and set to be converted to the wavelength C1 in the C band. As a result, the wavelength S1 in the S band of the wavelength division multiplexed signal light 1a branched by the input side WSS11aA is converted to the wavelength C1 in the C band by the wavelength band conversion unit #1A and output to the second input port of the output side WSS12b.

[0102] Similarly, in wavelength band conversion unit #1j connected to the input side WSS11aA, as shown by arrow Y2 in FIG. 14, the wavelength S2 in the S band of the optical signal is shifted to the longer wavelength side by a shift amount of <+4> and set to be converted to the wavelength C3 in the C band. As a result, the wavelength S2 in the S band of the above-mentioned branched wavelength division multiplexed signal light 1a is converted to the wavelength C3 in the C band by the wavelength band conversion unit #jA and output to the j-th input port of the output side WSS12b.

[0103] Also, in another set (1 + j) of wavelength band conversion units #1A connected to the input side WSS11aA, as shown by arrow Y3 in FIG. 14, the wavelength L3 in the L band of the optical signal is shifted to the shorter wavelength side by a shift amount of <-8> and set to be converted to the wavelength S1 in the S band. As a result, the wavelength L3 in the L band of the above-mentioned branched wavelength division multiplexed signal light 1a is converted to the wavelength S1 in the S band by another set (1 + j) of wavelength band conversion units #1A and output to the first input port of another set (1 + j) of the output side WSS12b.

[0104] Furthermore, in another set (1 + j) of wavelength band conversion units #jA connected to the input side WSS11aA, as shown by arrow Y4 in FIG. 14, the wavelength C3 in the C band of the optical signal is shifted to the shorter wavelength side by a shift amount of <-5> and set to be converted to the wavelength S1 in the S band. As a result, the wavelength C3 in the C band of the above-mentioned branched wavelength division multiplexed signal light 1a is converted to the wavelength S1 in the S band by another set (1 + j) of wavelength band conversion units #jA and output to the j-th input port of another set (1 + j) of the output side WSS12b.

[0105] In this way, the wavelength conversion units #1A to #jA of the wavelength cross-connect device 1A enable wavelength conversion across a plurality of wavelength bands in units of wavelengths in the wavelength-division multiplexed signal lights 1a to 1m.

[0106] <Modification Example 2 of the Embodiment> FIG. 15 is a block diagram showing the configuration of a wavelength cross-connect device according to Modification Example 2 of the embodiment of the present invention.

[0107] The wavelength cross-connect device 1B of Modification Example 2 shown in FIG. 15 is different from the wavelength cross-connect device 1 (FIG. 1) of the above embodiment in that the wavelength band switching unit 10B does not include <Q×1> WSSs 12a to 12m (FIG. 1). Further, the WXC unit 20B includes <Q×N> WSSs 21aB to 21mB instead of <1×N> WSSs 21a to 21m (FIG. 1), and the N output ports of the <Q×N> WSSs 21aB to 21mB are mesh-connected to the N input ports of the <N×1> WSSs 22a to 22m.

[0108] Note that the <Q×N> WSSs 21aB to 21mB constitute the third input-side WSS described in the claims.

[0109] The <Q×N> WSSs 21aB to 21mB include Q input ports and N output ports, and perform a process of selectively outputting the wavelength-division multiplexed signal lights input to the Q input ports from the <1×Q> WSSs 11a to 11m and the wavelength band switching processing units #1 to #j to any one of the output ports of the N output ports.

[0110] According to this configuration, the transmission of the optical signal between the wavelength band switching unit 10B and the WXC unit 20B can be realized by using an optical device (<Q×N> WSSs 21aB to 21mB) that can transmit with N wavelength-division multiplexed signal lights.

[0111] The <Q×N> WSSs 21aB to 21mB in the wavelength cross-connect device 1B shown in FIG. 15 can be similarly replaced and applied in the wavelength cross-connect device 1A shown in FIG. 13.

[0112] According to the above wavelength cross-connect devices 1, 1A, and 1B, by monitoring the usage status of the wavelength band switching units #1 to #j or the wavelength band conversion units #1A to #jA and dynamically turning off the power, it is possible to reduce the power consumption during operation. In addition, the wavelength shift amount in the wavelength band conversion units #1A to #jA can be arbitrarily selected, and even when any one of the wavelength band conversion units #1A to #jA fails, it is possible to suppress the impact of the failure by replacing it with another wavelength band conversion unit through remote control.

[0113] <Effect> (1) A wavelength cross-connect device, comprising: a wavelength band switching unit that branches each of the wavelength multiplexed signal lights obtained by multiplexing optical signals of different wavelength bands transmitted in a multi-band manner for each of a plurality of optical transmission paths composed of one or more optical fibers into a predetermined number, and performs wavelength band conversion on each of the branched wavelength multiplexed signal lights of the predetermined number and outputs them; a plurality of first input side WSSs that branch and output each of the wavelength multiplexed signal lights output from the wavelength band switching unit; and a plurality of first output side WSSs mesh-connected to the first input side WSSs, and a WXC (Wavelength Cross Connect) unit that inputs the wavelength multiplexed signal light branched by the first input side WSS into the first output side WSS, changes the path, and then outputs it to an output transmission path. The wavelength cross-connect device is characterized by comprising the above components.

[0114] According to this configuration, the wavelength cross-connect device can convert the wavelength band of the wavelength multiplexed signal light in which the optical signals of different wavelength bands transmitted in a multi-band manner are multiplexed by the wavelength band switching unit, and then change the path in the WXC unit and output it to the output side path.

[0115] Therefore, in a multi-band transmission system in which a plurality of nodes to which a wavelength cross-connect device is applied are link-connected (optically transmitted path-connected), wavelength band conversion can be performed in units of links and wavelengths. By this conversion, the wavelength of the free wavelength band of the optical transmission path in the node section (for example, the wavelength C1 in the C band) can be converted and used by the wavelength cross-connect device on the front side of the node section. Since the wavelength of the wavelength free section can be set to be usable in this way, the usage capacity of the network can be improved. That is, the utilization efficiency of the network of the multi-band transmission system can be improved.

[0116] (2) The wavelength band switching unit includes a plurality of second input side WSSs that branch and output each of the wavelength multiplexed signal lights for each optical transmission path to a predetermined number, and a wavelength band of the optical signal multiplexed in the wavelength multiplexed signal light branched and output by the second input side WSS is different. A plurality of wavelength band switching processing units that output wavelength multiplexed signal lights converted into wavelength bands, and the wavelength multiplexed signal lights output from the plurality of wavelength band switching processing units and the wavelength multiplexed signal lights directly output from the second input side WSS are selected one by one. The wavelength cross-connect device according to (1) above, further comprising a second output side WSS that outputs to the first input side WSS of the WXC unit.

[0117] According to this configuration, when the communication volume of the wavelength multiplexed signal light transmitted in multi-band increases and it is desired to increase the number of wavelength band switches in the wavelength band switching unit, it can be easily increased by increasing it in units of the wavelength band switching processing unit.

[0118] (3) The wavelength band switching processing unit includes a wavelength band demultiplexing unit that demultiplexes and outputs optical signals of different wavelength bands multiplexed in the wavelength multiplexed signal light from the second input side WSS, and among the demultiplexed optical signals of different wavelength bands, an input side conversion unit that converts optical signals of wavelength bands other than a predetermined specific wavelength band into optical signals of the specific wavelength band. It has the same number of input ports and output ports as the number of demultiplexing, can process only the specific wavelength band, and outputs from the output port so as to convert the specific wavelength band converted by the input side conversion unit input from the input port or the specific wavelength band within the different wavelength bands demultiplexed, into a predetermined wavelength band. A specific WSS, 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 a predetermined wavelength band, and a wavelength band multiplexing unit that multiplexes each optical signal of different wavelength bands from the output side conversion unit into wavelength multiplexed signal light and outputs it to the second output side WSS. The wavelength cross-connect device according to (2) above is characterized by comprising the same.

[0119] According to this configuration, by the specific WSS, the specific wavelength band converted by the input side conversion unit or the specific wavelength band within the different wavelength bands demultiplexed by the wavelength band demultiplexing unit is output from the output port so as to be converted into a predetermined wavelength band. In this way, each optical signal of different wavelength bands can be converted into an optical signal of a predetermined wavelength band by one specific WSS, so that the wavelength band switching processing unit can be miniaturized.

[0120] (4) The wavelength band switching processing unit includes a first WSS that branches different wavelength bands multiplexed in the wavelength multiplexed signal light from the second input side WSS to include a predetermined number of optical signals of the same wavelength band, and 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. It is configured to include a second WSS that multiplexes the optical signals of each wavelength band converted by the wavelength band conversion unit into wavelength multiplexed signal light and outputs it to the second output side WSS. The wavelength cross-connect device according to (2) above is characterized by comprising the same.

[0121] According to this configuration, with a wavelength band switching processing unit having a simple configuration, different wavelength bands multiplexed in the wavelength multiplexed signal light for each input transmission path can be converted into optical signals of other different wavelength bands.

[0122] (5) The second input-side WSS branches the wavelength-division multiplexed signal light for each optical transmission path into optical signals in any wavelength band, and performs a process of outputting the optical signal in any one of the branched wavelength bands from any one output port. Instead of the wavelength band switching processing unit, a wavelength band conversion unit is provided that converts the optical signal in one wavelength band output from one output port of the second input-side WSS into a different wavelength band. The wavelength cross-connect device according to (2) above is characterized in that.

[0123] According to this configuration, since the wavelength band conversion unit has a simpler and smaller configuration than the wavelength band switching processing unit, the wavelength cross-connect device can be downsized accordingly.

[0124] (6) The wavelength band conversion unit according to (5) above is characterized in that the wavelength of the optical signal in one wavelength band output from one output port of the second input-side WSS is shifted to the long wavelength side or the short wavelength side to be converted into the wavelength of a different wavelength band.

[0125] According to this configuration, wavelength band conversion in units of wavelengths of wavelength bands in the wavelength-division multiplexed signal light becomes possible.

[0126] (7) The wavelength band switching unit does not include the second output-side WSS. The WXC unit replaces the first input-side WSS and includes a plurality of input ports into which the wavelength-division multiplexed signal light output without conversion from the second input-side WSS and the wavelength-division multiplexed signal light output from the wavelength band switching processing unit are input, and a plurality of output ports mesh-connected to the input ports of the first output-side WSS. The third input-side WSS is provided, and the third input-side WSS selectively outputs the wavelength-division multiplexed signal light input without conversion from the second input-side WSS and the wavelength-division multiplexed signal light input from the wavelength band switching processing unit to any one of the plurality of output ports. The wavelength cross-connect device according to any one of (2) to (6) above is characterized in that.

[0127] According to this configuration, the transmission of optical signals between the wavelength band switching unit and the WXC unit can be realized by using optical devices (the second output side WSS and the second input side WSS) that can transmit with a plurality of wavelength division multiplexed signal lights.

[0128] In addition, regarding the specific configuration, appropriate changes can be made as appropriate without departing from the gist of the present invention.

Explanation of Reference Numerals

[0129] 1, 1A, 1B wavelength cross-connect device 10 wavelength band switching unit 11a~11m, 11aA~11mA <1×Q>WSS (second input side WSS) 12a~12m <Q×1>WSS (second output side WSS) 20 WXC unit 21a~21m <1×N>WSS (first input side WSS) 21aB~21mB <Q×N>WSS (third input side WSS) 22a~22m <N×1>WSS (first output side WSS) 31 wavelength band demultiplexing unit 32, 33 wavelength band conversion units (input side conversion units) 34 <K×K>WSS (specific WSS) 35, 36 wavelength band conversion units (output side conversion units) 37 wavelength band multiplexing unit 61 <1×P>WSS (first WSS) 62a~62f wavelength band conversion units 63 <P×1>WSS (second WSS) #1~#j wavelength band switching processing unit #1A~#jA wavelength band conversion units

Claims

1. The wavelength cross-connect device is For each of a plurality of optical transmission paths composed of one or a plurality of optical fibers, each wavelength-division multiplexed signal light obtained by multiplexing optical signals in different wavelength bands transmitted in a multi-band manner is branched into a predetermined number, and for each of the branched wavelength-division multiplexed signal lights having a predetermined number, a wavelength band switching unit that performs wavelength band conversion and outputs the result, A plurality of first input-side WSSs that branch and output each of the wavelength-division multiplexed signal lights output from the wavelength band switching unit, and a plurality of first output-side WSSs mesh-connected to the first input-side WSS. A WXC (Wavelength Cross Connect) unit that inputs the wavelength-division multiplexed signal light branched by the first input-side WSS to the first output-side WSS, performs a path change, and then outputs the result to an output transmission path is provided with The wavelength band switching unit is A plurality of second input-side WSSs that branch each of the wavelength-division multiplexed signal lights for each of the optical transmission paths into a predetermined number and output the result, A plurality of wavelength band switching processing units that output wavelength-division multiplexed signal lights in which the wavelength band of the optical signal multiplexed in the wavelength-division multiplexed signal light branched and output by the second input-side WSS is converted into a different wavelength band, A second output-side WSS that outputs the wavelength-division multiplexed signal lights output from the plurality of wavelength band switching processing units and the wavelength-division multiplexed signal lights directly output from the second input-side WSS to the first input-side WSS of the WXC unit one by one while selecting them A wavelength cross-connect device, characterized by comprising the above.

2. The wavelength band switching processing unit is A wavelength band demultiplexing unit that demultiplexes and outputs optical signals in different wavelength bands multiplexed in the wavelength-division multiplexed signal light from the second input-side WSS, An input-side conversion unit that converts an optical signal in a wavelength band other than a predetermined specific wavelength band among the demultiplexed optical signals in different wavelength bands into an optical signal in the specific wavelength band, It has the same number of input ports and output ports as the number of demultiplexed waves, can only process the specific wavelength band, and converts the specific wavelength band converted by the input-side conversion unit input from the input port or the specific wavelength band within the demultiplexed different wavelength bands into a predetermined wavelength band and outputs it from the output port, a specific WSS; 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 a predetermined wavelength band; It includes a wavelength-band multiplexer that multiplexes each optical signal of different wavelength bands from the output-side conversion unit into a wavelength-division multiplexed signal light and outputs it to the second output-side WSS. The wavelength cross-connect device according to claim 1, characterized in that.

3. The wavelength-band switching processing unit A first WSS that branches different wavelength bands multiplexed in the wavelength-division multiplexed signal light from the second input-side WSS to include a predetermined number of optical signals of the same wavelength band; The same number of wavelength-band conversion units as 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; It is configured to include a second WSS that multiplexes the optical signals of each wavelength band converted by the wavelength-band conversion unit into a wavelength-division multiplexed signal light and outputs it to the second output-side WSS. The wavelength cross-connect device according to claim 1, characterized in that.

4. The second input-side WSS branches the wavelength-division multiplexed signal light for each optical transmission path into an optical signal of any wavelength band, and performs a process of outputting the optical signal of any one wavelength band among the branched ones from any one output port. Instead of the wavelength-band switching processing unit, it includes a wavelength-band conversion unit that converts the optical signal of one wavelength band output from one output port of the second input-side WSS into a different wavelength band. The wavelength cross-connect device according to claim 1, characterized in that.

5. The wavelength-band conversion unit Shifting the wavelength of the optical signal in one wavelength band output from one output port of the second input-side WSS to the long-wavelength side or the short-wavelength side to convert it to a wavelength in a different wavelength band The wavelength cross-connect device according to claim 4, characterized in that

6. The wavelength band switching unit does not include the second output-side WSS, Instead of the first input-side WSS, the WXC unit includes a third input-side WSS having a plurality of input ports into which the wavelength-division multiplexed signal light output without conversion from the second input-side WSS and the wavelength-division multiplexed signal light output from the wavelength band switching processing unit are input, and a plurality of output ports mesh-connected to the input ports of the first output-side WSS, The third input-side WSS selectively outputs, to any one of the plurality of output ports, the wavelength-division multiplexed signal light input without conversion from the second input-side WSS and the wavelength-division multiplexed signal light input from the wavelength band switching processing unit to the plurality of input ports, The wavelength cross-connect device according to any one of claims 1 to 5, characterized in that

7. A wavelength cross-connect method by a wavelength cross-connect device, The wavelength cross-connect device includes a wavelength band switching unit and a WXC unit, The wavelength band switching unit, multiplexing each of the wavelength-division multiplexed signal lights in which the optical signals in different wavelength bands transmitted in a multi-band manner for each of the plurality of optical transmission paths composed of one or a plurality of optical fibers are multiplexed, and Q-branching them into a predetermined number; performing wavelength band conversion on each optical signal for each of the Q-branched wavelength-division multiplexed signal lights in a predetermined number; executing, The WXC unit, multiplexing each of the wavelength-division multiplexed signal lights in which the wavelength-converted optical signals are multiplexed and the non-converted wavelength-division multiplexed signal lights after Q-branching, N-branching them, changing the direction of the N-branched wavelength-division multiplexed signal lights, and outputting them to the output transmission path executing, The wavelength band switching unit includes a plurality of second input side WSSs, a plurality of wavelength band switching processing units, and a second output side WSS. The WXC unit includes a first input side WSS. The second input side WSS executes a step of branching each of the wavelength division multiplexed signal lights for each of the optical transmission paths into a predetermined number and outputting them. The wavelength band switching processing unit executes a step of outputting a wavelength division multiplexed signal light in which the wavelength band of the optical signal multiplexed in the wavelength division multiplexed signal light branched and output by the second input side WSS is converted into a different wavelength band. The second output side WSS executes a step of outputting the wavelength division multiplexed signal light output from the plurality of wavelength band switching processing units and the wavelength division multiplexed signal light directly output from the second input side WSS to the first input side WSS of the WXC unit while selecting them one by one. A wavelength cross-connect method characterized by the above.

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