Optical communication device, optical communication system, and communication method

Abstract

An optical communication device according to the present invention comprises optical branching / insertion units (132, 133), an optical cross-connect unit (131), and a path coupling / separation unit (138). The optical branching / insertion units (132, 133) comprise an insertion port for inserting an optical signal and a branching port for branching an optical signal. The optical cross-connect unit (131) connects the optical signal inserted from the insertion port to a path, connects the optical signal input from the path to another path, and connects the optical signal input from the path to the optical branching / insertion units such that said optical signal can be output from the branching port. The path coupling / separation unit (138) receives optical signals of multiple wavelengths that are inserted from the insertion port of the optical branching / insertion units, separates the optical signals by each path, aggregates each of the separated optical signals for each path of the transmission destination, and outputs the aggregated optical signal to the optical cross-connect unit, and receives, from the optical cross-connect unit, optical signals input from the plurality of optical paths, couples the optical signals for each branching port, and outputs the optical signals to the optical cross-connect unit.

Description

Optical communication device, optical communication system, and communication method

[0001] The present invention relates to an optical communication device, an optical communication system, and a communication method.

[0002] A ROADM (Reconfigurable Add / Drop Multiplexer), a conventional technology described in Non-Patent Document 1, has the functions of an optical cross-connect unit and an optical add / drop unit. The optical cross-connect unit rearranges optical wavelength-multiplexed signals input from each path and outputs them to another path. The optical cross-connect unit also inputs and outputs optical signals to the optical add / drop unit. The optical add / drop unit drops an optical signal of a specified wavelength to a specified port. It also adds an optical signal of a specified wavelength from a specified port.

[0003] As an optical add / drop unit for realizing a colorless, directionless, contentionless (CDC)-ROADM, Non-Patent Document 1 describes an optical add / drop unit using an optical multicast switch, and Non-Patent Document 2 describes an optical add / drop unit using an MxN wavelength selective switch (WSS: Wavelength Selective Switch).

[0004] 26 is a block diagram showing an example of the functional configuration of the above-mentioned conventional optical communication device. As shown in the figure, the conventional optical communication device 9001 is configured to include an optical cross-connect unit 9031 and an optical add / drop unit 9032.

[0005] In the conventional optical communication device 9001, optical signals are added or dropped as follows.

[0006] An optical signal added from the add port of the first add unit 90321 or the second add unit 90323 is passed from the first add unit 90321 or the second add unit 90323 to the first multiplexing unit 90312 and can be sent out from port 1A on the path 1 side. Also, an optical signal added from the add port of the first add unit 90321 or the second add unit 90323 is passed from the first add unit 90321 or the second add unit 90323 to the second multiplexing unit 90314 and can be sent out from port 2A on the path 2 side.

[0007] An optical signal received at port 1 on the path 1 side is demultiplexed by the first demultiplexing unit 90311, passed to the first branching unit 90322 or the second branching unit 90324, and can be output from the branch port of the first branching unit 90322 or the second branching unit 90324. In addition, an optical signal received at port 1 on the path 1 side is demultiplexed by the first demultiplexing unit 90311, passed to the first branching unit 90322 or the second branching unit 90324, and can be output from the branch port of the first branching unit 90322 or the second branching unit 90324.

[0008] Article: "Advanced and Economical Optical Multicast Switches, Essential for Improving the Flexibility of Optical Networks," Business Communication 2019, Vol. 56, No. 5. P.D. Colbourne, S. McLaughlin, C. Murley, S. Gaudet and D. Burke, "Contentionless Twin 8x24 WSS with Low Insertion Loss," 2018 Optical Fiber Communications Conference and Exposition (OFC), 2018, pp. 1-3.

[0009] In the prior art, when an optical multicast switch or an MxN WSS is used at least in an optical add / drop unit, in order to send optical signals to different paths, it was necessary to add optical signals for each path from different ports of the add / drop unit. Also, optical signals received from different paths had to be branched and extracted to different ports of the add / drop unit.

[0010] In other words, the conventional technology had the following problems: When multiple optical signals with different wavelengths were added from the same port of an optical add / drop unit, it was not possible to send each of these optical signals to different paths. Also, it was not possible to drop multiple optical signals with different wavelengths from different paths to the same port of the add / drop unit.

[0011] For example, the add and drop sections of an optical add / drop unit can be configured as follows. That is, an M-input, N-output add / drop unit can be configured by connecting the output port of an M-input, 1-output WSS to the input port of a 1-input, N-output WSS, and an N-input, M-output add / drop unit can be configured by connecting the output port of an N-input, 1-output WSS to the input port of a 1-input, M-output WSS. With such a configuration, multiple optical signals with different wavelengths can be added and dropped from the same port of the add / drop unit and sent to different paths. Also, multiple optical signals with different wavelengths coming from different paths can be dropped to the same port of the add / drop unit. However, with such a configuration, the aforementioned CDC (Colorless, Directionless, Contentionless) characteristics cannot be obtained.

[0012] The present invention has been made based on the above-mentioned problem recognition. That is, the present invention aims to provide an optical communication device, an optical communication system, and a communication method that, while based on a configuration that operates as a CDC-ROADM as long as a single optical signal is added from each port of an optical add / drop unit, can send each of multiple optical signals with different wavelengths to different paths when the multiple optical signals are added from the same port of the optical add / drop unit, or can drop multiple optical signals with different wavelengths from different paths to the same port of the add / drop unit.

[0013] [1] In order to solve the above problem, an optical communication device according to one aspect of the present invention comprises an optical add-drop unit having an add port for adding an optical signal and a drop port for dropping an optical signal; an optical cross-connect unit that connects an optical signal added from the add port to a route, connects an optical signal input from the route to another route, and connects the optical signal input from the route to the optical add-drop unit so that it can be output from the drop port; and a path coupling / separation unit that receives multi-wavelength optical signals added from the add port of the optical add-drop unit from the optical cross-connect unit, separates them by route, and combines each separated optical signal for each destination route and outputs it to the optical cross-connect unit, and receives optical signals input from the multiple routes from the optical cross-connect unit, combines them for each drop port, and outputs them to the optical cross-connect unit.

[0014] [2] Also, in one aspect, in the optical communication device of [1] above, the path coupling / separation unit includes a path separation unit that multiplexes optical signals from a plurality of the add ports and demultiplexes the multiplexed optical signals so that they are collected for each destination path, and a path coupling unit that multiplexes optical signals received from a plurality of the paths and demultiplexes the multiplexed optical signals so that they are collected for each target branch port.

[0015] [3] Also, in one aspect, in the optical communication device of [1] above, the optical signal inserted from a specific add port and sent to a specific path and the optical signal received from the specific path and output to a specific branch port corresponding to the specific add port have different wavelengths, and the path coupling / separation unit includes a multiplexing unit that combines the optical signals inserted from the multiple add ports and the optical signals received from the multiple paths, and a demultiplexing unit that demultiplexes the optical signals based on the optical signals combined by the multiplexing unit so that they are grouped for each destination path and so that they are grouped for each target branch port.

[0016] [4] Also, in one aspect, in the optical communication device of [1] above, the path coupling / separation unit comprises a path separation unit that rearranges optical signals from a plurality of add ports so that the optical signals are grouped for each destination path, and a path coupling unit that rearranges optical signals received from a plurality of paths so that the optical signals are grouped for each target branch port, wherein the path separation unit is configured using an M-input N-output wavelength rearrangement unit, and the path coupling unit is configured using an N-input M-output wavelength rearrangement unit, where M is the number of the optical add / drop units and N is the number of the paths, and the wavelength rearrangement unit outputs L optical signals by rearranging them based on the wavelengths of the K input optical signals, and is configured so that an optical signal of a predetermined wavelength contained in any optical signal of the K input optical signals can be output as an optical signal of the L output optical signals.

[0017] [5] Also, in one aspect, in the optical communication device of [1] above, an optical signal that is added from a specific add port and sent to a specific path, and an optical signal that is received from the specific path and output to a specific drop port corresponding to the specific add port, have mutually different wavelengths, the path coupling / separation unit is configured using an (M+N) input (M+N) output wavelength recombination unit, where M is the number of the optical drop / add units and N is the number of the paths, the wavelength recombination unit outputs L optical signals by recombining based on the wavelengths of the K input optical signals, and an optical signal of a predetermined wavelength contained in any optical signal of the K input optical signals is configured to be output as an optical signal of the L output optical signals.

[0018] [6] Also, in one aspect, in any of the optical communication devices [1] to [5] above, the optical cross-connect unit passes the optical signal inserted from a specific one of the add ports to the path coupling / separation unit, and the path coupling / separation unit combines the optical signal inserted from the specific one of the add ports passed from the optical cross-connect unit so as to become part of the optical signal output from the specific one of the branch ports.

[0019] [7] Another aspect is a communication system, comprising: the optical communication device according to any one of [1] to [6] above; and one or more optical transceivers that transmit optical signals to the add ports of the optical add / drop unit of the optical communication device to be sent to the plurality of paths, and receive optical signals received from the plurality of paths from the drop ports of the optical add / drop unit of the optical communication device.

[0020] [8] Also, a communication method in which an optical communication device adds a first optical signal to a path and drops a second optical signal from a path, the method comprising: inputting the first optical signal to be added to a path from an add port of an optical add / drop unit; passing the first optical signal input from the add port to a path coupling / separation unit; the path coupling / separation unit receiving the first optical signal from the optical cross connect unit and separating it for each path; the path coupling / separation unit passing the separated first optical signal to the optical cross connect unit for each path; and the optical cross connect unit separating the separated first optical signal for each path. the optical cross-connect unit receives the second optical signals to be branched from a plurality of paths and passes them to the path coupling / separation unit, the path coupling / separation unit receives the second optical signals received from the plurality of paths from the optical cross-connect unit and combines them for each branch port of the optical drop-and-insert unit, the optical cross-connect unit receives the second optical signals combined for each branch port from the path coupling / separation unit and passes them to the optical drop-and-insert unit having a target branch port, and the second optical signals received by the optical drop-and-insert unit are output from the target branch port.

[0021] According to the present invention, an optical communication device can add multiple optical signals with different wavelengths from the same add port of an add / drop unit while obtaining CDC characteristics, and can transmit the optical signals with each wavelength to different paths.Furthermore, the optical communication device can drop and output multiple optical signals with different wavelengths from different paths to the same drop port of the add / drop unit while obtaining CDC characteristics.

[0022] FIG. 1 is a block diagram showing a schematic functional configuration of an optical communication device according to a first embodiment of the present invention. FIG. 1 is a schematic diagram for explaining an example of a path of an optical signal to be inserted into an optical add-drop unit in the optical communication device of the first embodiment. FIG. 1 is a schematic diagram for explaining an example of a path of an optical signal to be dropped from the optical add-drop unit in the optical communication device of the first embodiment. FIG. 2 is a block diagram showing a schematic functional configuration of an optical communication device according to a second embodiment. FIG. 2 is a schematic diagram showing a path of an optical signal when an optical signal input from an add port of a first add unit of the optical communication device of the second embodiment is sent to a path side. FIG. 3 is a schematic diagram showing a path of an optical signal when an optical signal received from a path side is dropped from a drop port of a first drop unit in the optical communication device of the second embodiment. FIG. 3 is a schematic diagram showing a path of an optical signal when an optical signal input from an add port of a second add unit of the optical communication device of the second embodiment is sent to a path side. FIG. 4 is a schematic diagram showing a path of an optical signal when an optical signal received from a path side is output from a drop port of a second drop unit in the optical communication device of the second embodiment. 10 is a schematic diagram showing the path of an optical signal when an optical signal input from an add port of a first add unit of an optical communication device of a third embodiment is sent to a path side. FIG. 11 is a schematic diagram showing the path of an optical signal when an optical signal received from a path side is output from a branch port of a first branch unit in the optical communication device of the third embodiment. FIG. 12 is a block diagram showing the schematic functional configuration of an optical communication device according to a fourth embodiment. FIG. 13 is a block diagram showing an example of the functional configuration of a wavelength recombination unit that can function as a path separation unit or a path coupling unit in the fourth embodiment. FIG. 14 is a block diagram showing another example of the functional configuration of a wavelength recombination unit that can function as a path separation unit or a path coupling unit in the fourth embodiment. FIG. 15 is a block diagram showing the schematic functional configuration of an optical communication device according to a fifth embodiment. FIG. 16 is a block diagram showing the schematic functional configuration of an optical communication device according to a sixth embodiment. FIG. 17 is a schematic diagram for explaining the path of an optical signal when an optical signal added from an add port of a first branch unit of an optical communication device of the sixth embodiment is sent to a path side. FIG. 18 is a schematic diagram showing the path of an optical signal when an optical signal received from a path side is output from a branch port of a first branch unit in the optical communication device of the sixth embodiment.10 is a schematic diagram for explaining the path of an optical signal when an optical signal inserted from a first insert unit of an optical communication device of a seventh embodiment is sent to a path side. FIG. 11 is a schematic diagram showing the path of an optical signal when an optical signal received from a path side is output from a branch port of a first branch unit in an optical communication device of the seventh embodiment. FIG. 12 is a block diagram showing the schematic functional configuration of an optical communication device according to an eighth embodiment. FIG. 13 is a schematic diagram for explaining the path of an optical signal when an optical signal is folded back between an optical add-drop unit (832) and an optical add-drop unit (833) in an optical communication device of the eighth embodiment. FIG. 14 is a block diagram showing the schematic functional configuration of an optical communication system according to a ninth embodiment. FIG. 15 is a block diagram showing the internal configuration of a computer when an optical communication device is realized using a computer in the first to ninth embodiments. FIG. 16 is a block diagram showing the schematic functional configuration of an optical communication device according to prior art.

[0023] The following describes several embodiments of the present invention, in which optical communication devices communicate using WDM (wavelength division multiplexing) signals in which light of multiple wavelengths is multiplexed.

[0024] The features of each of the following embodiments are as follows: That is, the optical communication device includes a path coupling / separation unit. The path coupling / separation unit is a means for combining / separating multi-wavelength add / drop signals. With these features, when multiple optical signals with different wavelengths are added from the same port of the optical add / drop unit, these optical signals can be sent to different paths. Also, multiple optical signals with different wavelengths coming from different paths can be dropped to the same port of the optical add / drop unit.

[0025] Optical communication devices input and output optical signals that are multi-wavelength optical signals. Optical elements included in the devices process the optical signals based on wavelength. The optical elements can separate or combine optical signals. By combining these optical elements, the optical communication device can direct optical signals of specific wavelengths to specific paths.

[0026] [First Embodiment] Fig. 1 is a block diagram showing a schematic functional configuration of an optical communication device according to a first embodiment. As shown in the figure, the optical communication device 1 includes an optical cross-connect unit 131, an optical add / drop unit 132, an optical add / drop unit 133, and a path coupling / separation unit 138. Each functional unit constituting the optical communication device 1 is realized mainly using elements for processing optical signals. The function of each unit is as described below.

[0027] The optical cross-connect unit 131 connects the paths of optical signals between the direction side, the optical add-drop unit 132 or the optical add-drop unit 133, and the direction coupling / separation unit 138. By connecting the paths with the optical cross-connect unit 131, optical signals are passed in both directions between the direction side, the optical add-drop unit 132 or the optical add-drop unit 133, and the direction coupling / separation unit 138.

[0028] Each of the optical add / drop units 132 and 133 passes an optical signal of a predetermined wavelength that is added from an add port to the optical cross-connect unit 131. Furthermore, each of the optical add / drop units 132 and 133 drops and outputs the optical signal of a predetermined wavelength that is passed from the optical cross-connect unit 131 to a predetermined drop port.

[0029] The path coupling / separation unit 138 branches, to different paths, multi-wavelength optical signals that are added from predetermined ports of the optical add / drop units 132 and 133. The path coupling / separation unit 138 also combines optical signals from different paths and branches the combined signals to predetermined ports of the optical add / drop units 132 and 133. When the path coupling / separation unit 138 exchanges optical signals with the optical add / drop units 132 and 133, the optical signals are exchanged via the optical cross-connect unit 131.

[0030] By having the path coupling / separation unit 138, the optical communication device 1 can send out the optical signals of each wavelength to different paths when multiple optical signals of different wavelengths are added from the same port of the optical add / drop unit 132 or 133. Furthermore, the optical communication device 1 can drop and output multiple optical signals of different wavelengths received from different paths to the same port of the optical add / drop unit 132 or 133.

[0031] At this time, the optical cross-connect unit 131 appropriately connects the respective paths of the optical signal to be output from the optical add / drop unit 132 or 133 to the path side, the optical signal to be passed from the optical add / drop unit 132 or 133 to the path coupling / separation unit 138, the optical signal to be passed from the path side to the optical add / drop unit 132 or 133, the optical signal to be passed from the path side to the path coupling / separation unit 138, the optical signal to be passed from the path side to another path side, the optical signal to be passed from the path coupling / separation unit 138 to the path side, and the optical signal to be passed from the path coupling / separation unit 138 to the optical add / drop unit 132 or 133.

[0032] That is, each of the optical add / drop units 132 and 133 has an add port for adding an optical signal and a drop port for dropping an optical signal. The optical cross-connect unit 131 connects an optical signal added from the add port to a route, connects an optical signal input from the route to another route, and connects to the optical add / drop units (132, 133) so that the optical signal input from the route can be output from the drop port. The path coupling / separation unit 138 receives multi-wavelength optical signals added from the add ports of the optical add / drop units (132, 133) from the optical cross-connect unit (131), separates them by route, and combines each of the separated optical signals for each destination route and outputs them to the optical cross-connect unit (131), and also receives optical signals input from the plurality of routes from the optical cross-connect unit (131), combines them for each drop port, and outputs them to the optical cross-connect unit (131). Furthermore, the optical cross-connect unit 131 receives the optical signals combined for each path by the path coupling / separation unit (138) from the path coupling / separation unit (138) and sends them toward the target path, and passes the optical signals received from the paths to the path coupling / separation unit (138) and passes the optical signals combined for each branch port by the path coupling / separation unit (138) to the optical branching / insertion unit (132, 133) having the target branch port.

[0033] 2 is a schematic diagram illustrating an example of the path of an optical signal added to the optical add / drop unit 132 in the optical communication device 1 of this embodiment. In the example shown in this figure, two optical signals with different wavelengths are input to one of the add ports of the optical add / drop unit 132. The optical add / drop unit 132 passes these two signals to the optical cross connect unit 131. The optical cross connect unit 131 passes these two signals to the path coupling / separation unit 138 instead of directly directing them to each path. The path coupling / separation unit 138 separates these two signals and returns them to the optical cross connect unit 131. The optical cross connect unit 131 outputs the first of the separated optical signals from port 1A on the path 1 side and the second from port 2A on the path 2 side.

[0034] 3 is a schematic diagram showing an example of a path through which optical signals are input from port 1 on the path 1 side and port 2 on the path 2 side in the optical communication device 1 of this embodiment and then branched from the optical add / drop unit 132. The wavelength of the optical signal input from port 1 is different from the wavelength of the optical signal input from port 2. In this example, the optical cross-connect unit 131 does not directly pass the signal input from port 1 on the path 1 side and the signal input from port 2 on the path 2 side to the path coupling / separation unit 138, but passes them on to the path coupling / separation unit 138. The path coupling / separation unit 138 combines these two signals with different wavelengths and returns them to the optical cross-connect unit 131. The optical cross-connect unit 131 passes this combined optical signal to the optical add / drop unit 132. The optical add / drop unit 132 outputs the received optical signal from one of the branch ports.

[0035] As described above, according to this embodiment, it becomes possible to send each optical signal to a different path when multiple optical signals with different wavelengths are added from the same add port of the optical add / drop unit 132 or 133. It also becomes possible to drop multiple optical signals with different wavelengths from different paths to the same drop port of the optical add / drop unit 132 or 133.

[0036] Second Embodiment Next, a second embodiment of the present invention will be described. Note that the description of the matters already described in the previous embodiment may be omitted. Here, the description will focus on matters unique to this embodiment.

[0037] 4 is a block diagram showing a schematic functional configuration of an optical communication device according to a second embodiment. As shown in the figure, the optical communication device 2 includes an optical cross connect unit 231, an optical add / drop unit 232, an optical add / drop unit 233, and a path coupling / separation unit 238. In the optical communication device 2, the optical cross connect unit 231, the optical add / drop unit 232, the optical add / drop unit 233, and the path coupling / separation unit 238 each have the same functions as the optical cross connect unit 131, the optical add / drop unit 132, the optical add / drop unit 133, and the path coupling / separation unit 138 shown in FIG. 4 shows a more detailed internal configuration of each of the optical cross connect unit 231, the optical add / drop unit 232, the optical add / drop unit 233, and the path coupling / separation unit 238.

[0038] As shown in the figure, the optical cross-connect unit 231 includes a first demultiplexing unit 2311 , a first multiplexing unit 2312 , a second demultiplexing unit 2313 , and a second multiplexing unit 2314 .

[0039] The optical add / drop section 232 includes a first add section 2321 and a first drop section 2322. The optical add / drop section 233 includes a second add section 2331 and a second drop section 2332.

[0040] The path coupling / separating unit 238 includes a third multiplexing unit 2381 , a third demultiplexing unit 2382 , a fourth multiplexing unit 2383 , and a fourth demultiplexing unit 2384 .

[0041] The functions of the components of the optical communication device 2 are as follows.

[0042] The first demultiplexing unit 2311 demultiplexes the optical signal input from port 1 on the direction 1 side, and directs the demultiplexed optical signal to the fourth multiplexing unit 2383, the second multiplexing unit 2314, the first branching unit 2322, and the second branching unit 2332.

[0043] The second demultiplexing unit 2313 demultiplexes the optical signal input from port 2 on the direction 2 side, and directs the demultiplexed optical signal to the fourth multiplexing unit 2383, the first multiplexing unit 2312, the first branching unit 2322, and the second branching unit 2332.

[0044] The first multiplexing unit 2312 multiplexes the optical signals passed from the third demultiplexing unit 2382, the second demultiplexing unit 2313, the first insertion unit 2321, and the second insertion unit 2331, and outputs the multiplexed optical signal from port 1A on the direction 1 side.

[0045] The second multiplexing unit 2314 multiplexes the optical signals passed from the third demultiplexing unit 2382, the first demultiplexing unit 2311, the first inserting unit 2321, and the second inserting unit 2331, and outputs the multiplexed optical signal from port 2A on the direction 2 side.

[0046] The first adding unit 2321 passes an optical signal added from its own add port to the first multiplexing unit 2312, the second multiplexing unit 2314, and the third multiplexing unit 2381. The second adding unit 2331 also passes an optical signal added from its own add port to the first multiplexing unit 2312, the second multiplexing unit 2314, and the third multiplexing unit 2381.

[0047] The first branching unit 2322 branches and outputs, from a branching port, the optical signals passed from the first demultiplexing unit 2311, the second demultiplexing unit 2313, and the fourth demultiplexing unit 2384. The second branching unit 2332 branches and outputs, from a branching port, the optical signals passed from the first demultiplexing unit 2311, the second demultiplexing unit 2313, and the fourth demultiplexing unit 2384.

[0048] In the path coupling / separation unit 238, the third multiplexing unit 2381 multiplexes the optical signal received from the first inserting unit 2321 with the optical signal received from the second inserting unit 2331, and passes the multiplexed optical signal to the third demultiplexing unit 2382. The third demultiplexing unit 2382 also demultiplexes the optical signal passed from the third multiplexing unit 2381, and passes the demultiplexed optical signals to the first multiplexing unit 2312 and the second multiplexing unit 2314. In other words, the path coupling / separation unit 238 directs the optical signals added in the first inserting unit 2321 or the second inserting unit 2331 to the path 1 side and the path 2 side.

[0049] In the path coupling / separation unit 238, the fourth multiplexing unit 2383 multiplexes the optical signal passed from the first demultiplexing unit 2311 and the optical signal passed from the second demultiplexing unit 2313, and passes the multiplexed optical signal to the fourth demultiplexing unit 2384. The fourth demultiplexing unit 2384 demultiplexes the optical signal passed from the fourth multiplexing unit 2383, and passes the demultiplexed optical signals to the first branching unit 2322 and the second branching unit 2332. In other words, the path coupling / separation unit 238 redirects the optical signal received from the path 1 side and the optical signal received from the path 2 side so that they can be branched and output from the first branching unit 2322 and the second branching unit 2332.

[0050] That is, the path coupling / separation unit 238 can be configured by connecting the third multiplexing unit 2381 and the third demultiplexing unit 2382 back-to-back, and by connecting the fourth multiplexing unit 2383 and the fourth demultiplexing unit 2384 back-to-back. Note that a wavelength selective switch (WSS) or an optical coupler can be used as the third multiplexing unit 2381 or the fourth multiplexing unit 2383. A wavelength selective switch (WSS) or an optical splitter can be used as the third demultiplexing unit 2382 or the fourth multiplexing unit 2383.

[0051] In order to compensate for the loss that the optical signal experiences when passing through each section shown in FIG. 4, optical amplifiers may be placed at appropriate locations.

[0052] 5 is a schematic diagram showing the paths of optical signals when an optical signal input from an add port of the first add unit 2321 of the optical communication device 2 is sent to the path 1 side and the path 2 side, respectively. Two signals with different wavelengths are input from one add port of the first add unit 2321. These two signals are referred to as signal 1 and signal 2. Signal 1 and signal 2 are passed from the first add unit 2321 to the third multiplexer 2381 via route R101. Signal 1 and signal 2 are passed from the third multiplexer 2381 to the third demultiplexer 2382 via route R102. The third demultiplexer 2382 demultiplexes signal 1 and signal 2. Signal 1 is passed from the third demultiplexer 2382 to the first multiplexer 2312 via route R103. The first multiplexer 2312 outputs signal 1 from port 1A on the path 1 side. Meanwhile, signal 2 is passed from the third demultiplexer 2382 through route R104 to the second multiplexer 2314. The second multiplexer 2314 outputs signal 2 from port 2A on the path 2 side.

[0053] In other words, optical signals of multiple wavelengths input from one add port of the first add section 2321 are separated in the path coupling / separation section 238 and sent out from port 1A on the path 1 side and port 2A on the path 2 side, respectively.

[0054] FIG. 6 is a schematic diagram showing the paths of optical signals received from the path 1 side and the path 2 side when they are output from the branch ports of the first branching unit 2322 of the optical communication device 2. Two signals with different wavelengths are received at port 1 on the path 1 side and port 2 on the path 2 side. These two signals are referred to as signal 3 and signal 4, respectively. Signals 3 and 4 are signals to be branched in the optical communication device 2. Signal 3 input to the first demultiplexing unit 2311 is passed to the fourth multiplexing unit 2383 via route R105. Signal 4 input to the second demultiplexing unit 2313 is passed to the fourth multiplexing unit 2383 via route R106. The fourth multiplexing unit 2383 multiplexes signal 3 and signal 4. The combined signals 3 and 4 are passed to the fourth demultiplexing unit 2384 via route R107. Signals 3 and 4 are passed from fourth demultiplexer 2384 through route R108 to first branching unit 2322. Signals 3 and 4 are then output from one branch port that first branching unit 2322 has.

[0055] In other words, optical signals of different wavelengths received at port 1 on the path 1 side and port 2 on the path 2 side are combined in the path coupling / separation unit 238 and output from one branch port of the first branching unit 2322.

[0056] 7 is a schematic diagram showing the paths of optical signals when optical signals input from an add port of the second add unit 2331 of the optical communication device 2 are sent to the path 1 side and the path 2 side, respectively. Two signals with different wavelengths are input from one add port of the second add unit 2331. These two signals are referred to as signal 5 and signal 6. Signals 5 and 6 are passed from the second add unit 2331 to the third multiplexer 2381 via route R111. Signals 5 and 6 are passed from the third multiplexer 2381 to the third demultiplexer 2382 via route R112. The third demultiplexer 2382 demultiplexes signal 5 and signal 6. Signal 5 is passed from the third demultiplexer 2382 to the first multiplexer 2312 via route R113. The first multiplexer 2312 outputs signal 5 from port 1A on the path 1 side. Meanwhile, signal 6 is passed from the third demultiplexer 2382 through route R114 to the second multiplexer 2314. The second multiplexer 2314 outputs signal 6 from port 2A on the path 2 side.

[0057] In other words, optical signals of multiple wavelengths input from one add port of the second add section 2331 are separated in the path coupling / separation section 238 and sent out from port 1A on the path 1 side and port 2A on the path 2 side, respectively.

[0058] FIG. 8 is a schematic diagram showing the paths of optical signals received from the path 1 side and the path 2 side when they are output from the branch ports of the second branching unit 2332 of the optical communication device 2. Two signals with different wavelengths are received at port 1 on the path 1 side and port 2 on the path 2 side. These two signals are referred to as signal 7 and signal 8, respectively. Signals 7 and 8 are signals to be branched in the optical communication device 2. Signal 7 input to the first demultiplexing unit 2311 is passed to the fourth multiplexing unit 2383 via route R115. Signal 8 input to the second demultiplexing unit 2313 is passed to the fourth multiplexing unit 2383 via route R116. The fourth multiplexing unit 2383 multiplexes signal 7 and signal 8. The combined signals 7 and 8 are passed to the fourth demultiplexing unit 2384 via route R117. Signals 7 and 8 are passed from fourth demultiplexer 2384 through route R118 to second branching unit 2332. Signals 7 and 8 are then output from one branch port that second branching unit 2332 has.

[0059] In other words, optical signals of different wavelengths received at port 1 on the path 1 side and port 2 on the path 2 side are combined in the path coupling / separation unit 238 and output from one branch port of the second branching unit 2332.

[0060] In this embodiment (FIGS. 4 to 8), the corresponding optical signals in both the up and down directions may be signals with the same wavelength.

[0061] As described above, in this embodiment, the path coupling / separation unit 238 includes a path separation unit and a path combination unit. The path separation unit multiplexes optical signals from multiple add ports and demultiplexes the multiplexed optical signals so that they are collected for each destination path. The combination of the third multiplexing unit 2381 and the third demultiplexing unit 2382 corresponds to the path separation unit. Furthermore, the path coupling unit multiplexes optical signals received from multiple paths and demultiplexes the multiplexed optical signals so that they are collected for each destination branch port. The combination of the fourth multiplexing unit 2383 and the fourth demultiplexing unit 2384 corresponds to the path coupling unit.

[0062] [Third Embodiment] Next, a third embodiment of the present invention will be described. Note that the description of the matters already described in the previous embodiments may be omitted. Here, the description will focus on matters unique to this embodiment.

[0063] The third embodiment is based on the premise that the corresponding optical signals in the up and down directions can be set to different wavelengths. In this case, the configuration of the optical coupling / decoupling device can be simplified compared to the second embodiment. In other words, the optical coupling / decoupling device can be realized with a pair of multiplexing and decoupling units.

[0064] 9 is a block diagram showing a schematic functional configuration of an optical communication device according to the third embodiment. As shown in the figure, the optical communication device 3 includes an optical cross-connect unit 331, an optical add / drop unit 332, an optical add / drop unit 333, and a direction coupling / separation unit 338. The optical cross-connect unit 331 includes a first demultiplexing unit 3311, a first multiplexing unit 3312, a second demultiplexing unit 3313, and a second multiplexing unit 3314. The optical add / drop unit 332 includes a first add unit 3321 and a first drop unit 3322. The optical add / drop unit 333 includes a second add unit 3331 and a second drop unit 3332.

[0065] The path coupling / separation unit 338 of this embodiment is configured to include a third multiplexing unit 3381 and a third demultiplexing unit 3382. The path coupling / separation unit 338 of this embodiment does not need to have two pairs of multiplexing units and demultiplexing units, as does the path coupling / separation unit 238 of the second embodiment ( FIG. 4 ). In other words, the path coupling / separation unit 338 is realized with only one pair of multiplexing unit (third multiplexing unit 3381) and demultiplexing unit (third demultiplexing unit 3382).

[0066] The third multiplexing unit 3381 multiplexes the optical signal passed from the first demultiplexing unit 3311, the optical signal passed from the second demultiplexing unit 3313, the optical signal passed from the first adding unit 3321, and the optical signal passed from the second adding unit 3331. The third multiplexing unit 3381 passes the multiplexed optical signal to the third demultiplexing unit 3382.

[0067] The third demultiplexing unit 3382 demultiplexes the optical signal passed from the third multiplexing unit 3381 according to the destination. The third demultiplexing unit 3382 passes the demultiplexed optical signals to the first multiplexing unit 3312, the second multiplexing unit 3314, the first branching unit 3322, and the second branching unit 3332, respectively.

[0068] FIG. 10 is a schematic diagram showing the paths of optical signals when an optical signal input from an add port of the first add unit 3321 of the optical communication device 3 is sent to the path 1 side and the path 2 side, respectively. Two signals with different wavelengths are input from one add port of the first add unit 3321. These two signals are referred to as signal 9 and signal 10. Signals 9 and 10 are passed from the first add unit 3321 to the third multiplexer 3381 via route R121. Signals 9 and 10 are passed from the third multiplexer 3381 to the third demultiplexer 3382 via route R122. The third demultiplexer 3382 demultiplexes signal 9 and signal 10. Signal 9 is passed from the third demultiplexer 3382 to the first multiplexer 3312 via route R123. The first multiplexer 3312 outputs signal 9 from port 1A on the path 1 side. Meanwhile, signal 10 is passed from the third demultiplexer 3382 through route R124 to the second multiplexer 3314. The second multiplexer 3314 outputs signal 10 from port 2A on the path 2 side.

[0069] In other words, optical signals of multiple wavelengths input from one add port of the first add section 3321 are separated in the path coupling / separation section 338 and sent out from port 1A on the path 1 side and port 2A on the path 2 side, respectively.

[0070] FIG. 11 is a schematic diagram showing the paths of optical signals received from the path 1 side and the path 2 side when they are output from the branch ports of the first branching unit 3322 of the optical communication device 3. Two signals with different wavelengths are received at port 1 on the path 1 side and port 2 on the path 2 side. These two signals are referred to as signal 11 and signal 12, respectively. Signals 11 and 12 are signals to be branched in the optical communication device 3. Signal 11 input to the first demultiplexing unit 3311 is passed to the third multiplexing unit 3381 via route R125. Signal 12 input to the second demultiplexing unit 3313 is passed to the third multiplexing unit 3381 via route R126. The third multiplexing unit 3381 multiplexes these signals 11 and 12. The combined signals 11 and 12 are passed to the third demultiplexing unit 3382 via route R127. Signals 11 and 12 are passed from third demultiplexing unit 3382 through route R128 to first branching unit 3322. Signals 11 and 12 are then output from one branch port that first branching unit 3322 has.

[0071] In other words, optical signals of different wavelengths received at port 1 on the path 1 side and port 2 on the path 2 side are combined in the path coupling / separation unit 338 and output from one branch port of the first branching unit 3322.

[0072] 10 and 11 , the corresponding uplink and downlink optical signals are set to different wavelengths for the optical communication device 3. Therefore, the path coupling / separation unit 338 can be realized by only one pair of multiplexing unit and demultiplexing unit. That is, the path coupling / separation unit 338 can be realized by only one pair of the third multiplexing unit 3381 and the third demultiplexing unit 3382.

[0073] 10 and 11 have been described above with reference to the optical signal added from the first adding unit 3321 and the optical signal dropped from the first dropping unit 3322. The optical communication device 3 can perform similar processing on the optical signal added from the second adding unit 3331 and the optical signal dropped from the second dropping unit 3332.

[0074] As described above, in this embodiment, the optical signal added from a specific add port and sent to a specific path and the optical signal received from the specific path and output to a specific drop port corresponding to the specific add port have different wavelengths. In the configuration of this embodiment, the path coupling / separation unit includes a third multiplexing unit 3381 (multiplexing unit) and a third demultiplexing unit 3382 (demultiplexing unit). The third multiplexing unit 3381 (multiplexing unit) combines the optical signals added from multiple add ports with the optical signals received from multiple paths. The third multiplexing unit 3381 (multiplexing unit) passes the combined optical signal to the third demultiplexing unit 3382 (demultiplexing unit). The third demultiplexing unit 3382 (demultiplexing unit) demultiplexes the optical signals based on the optical signals combined by the third multiplexing unit 3381 (multiplexing unit) so that the signals are combined for each destination path and for each target drop port.

[0075] [Fourth Embodiment] Next, a fourth embodiment of the present invention will be described. Note that the description of the matters already described in the previous embodiments may be omitted. Here, the description will focus on matters unique to this embodiment.

[0076] The fourth embodiment is characterized in that the path coupling / separation unit is configured using an M-input N-output path separation unit and an N-input M-output path combination unit.

[0077] 12 is a block diagram showing a schematic functional configuration of an optical communication device according to the fourth embodiment. As shown in the figure, the optical communication device 4 includes an optical cross-connect unit 431, an optical add / drop unit 432, an optical add / drop unit 433, and a path coupling / separation unit 438. Note that optical amplifiers may be disposed at appropriate locations to compensate for losses incurred by optical signals when passing through each unit within the optical communication device 4.

[0078] 12, for example, the number of optical add / drop units is 2, and the number of paths is 2. However, in general, the number of optical add / drop units may be M (M is a predetermined integer equal to or greater than 1), and the number of paths may be N (N is a predetermined integer equal to or greater than 1).

[0079] The optical cross-connect unit 431 is configured to include a first demultiplexing unit 4311, a first multiplexing unit 4312, a second demultiplexing unit 4313, and a second multiplexing unit 4314. The optical add / drop unit 432 is configured to include a first add unit 4321 and a first drop unit 4322. The optical add / drop unit 433 is configured to include a second add unit 4331 and a second drop unit 4332.

[0080] As described above, the path coupling / separation unit 438 in this embodiment includes a path separation unit 4381 and a path coupling unit 4382 .

[0081] The path separation unit 4381 separates the multi-wavelength optical signals added from the optical add / drop units 432 and 433, etc., into signals for each output path. The path separation unit 4381 is realized using an MxN wavelength recombination means. As described above, the path separation unit 4381 has M inputs and N outputs. M is the number of optical add / drop units and may be a predetermined integer greater than or equal to 1. N is the number of paths and may be a predetermined integer greater than or equal to 1.

[0082] That is, optical signals from M optical add / drop units are input to each of the M inputs of the path separation unit 4381. In the configuration shown in FIG. 12 (M=2), multi-wavelength optical signals from the first add unit 4321 and the second add unit 4331 are input to the path separation unit 4381. The path separation unit 4381 rearranges these optical signals according to wavelength to generate signals for N paths. The signals for each path are also multi-wavelength signals. Each of the N outputs from the path separation unit 4381 is to be sent to the N paths. In the configuration shown in FIG. 12 (N=2), the outputs from the path separation unit 4381 are passed to the first multiplexer 4312 and the second multiplexer 4314.

[0083] The path combiner 4382 combines optical signals received from multiple paths, such as path 1 and path 2, and directs the combined signals to the optical add / drop units 432 and 433. The path combiner 4382 is realized using an NxM wavelength recombination means, where M and N are as described above.

[0084] That is, optical signals received from N paths are input to each of the N inputs of the path coupler 4382. In the configuration shown in FIG. 12 (N=2), multi-wavelength optical signals from the first demultiplexer 4311 and the second demultiplexer 4313 are input to the path coupler 4382. The path coupler 4382 rearranges these optical signals according to their wavelengths to generate signals for M branch destinations. That is, optical signals are passed from the path coupler 4382 to each of the N optical add / drop units. The optical signals to these N optical add / drop units are also multi-wavelength signals. In the configuration shown in FIG. 12 (M=2), the output from the path coupler 4382 is passed to the first brancher 4322 and the second brancher 4332.

[0085] 13 and 14, a description will be given of a configuration for realizing the path separation unit 4381 and the path combination unit 4382. As will be described later, the wavelength recombination unit 4401 (FIG. 13) and the wavelength recombination unit 4401 (FIG. 14) can function as the path separation unit 4381 in FIG. 12 or as the path combination unit 4382.

[0086] FIG. 13 is a block diagram showing an example of the internal functional configuration of the wavelength recombining unit 4401. The wavelength recombining unit 4401 functions as a wavelength recombining means with K inputs and L outputs. Note that K and L are each a predetermined integer greater than or equal to 1. As shown in the figure, the wavelength recombining unit 4401 includes K 1xL WSSs 44011 and L optical couplers 44012. The K 1xL WSSs 44011 correspond to the K inputs of the wavelength recombining unit 4401. The input to one 1xL WSS 44011 may include L optical signals with different wavelengths. The 1xL WSS 44011 separates and distributes the L input optical signals and passes each of the signals to the L optical couplers 44012. The L optical couplers 44012 correspond to the L outputs of the wavelength recombining unit 4401, respectively. Optical signals with different wavelengths are passed to one optical coupler 44012 from each of the K 1xL WSSs 44011. The one optical coupler 44012 couples and outputs these K optical signals. With this configuration, the wavelength recombination unit 4401 recombines the K input optical signals and outputs L optical signals.

[0087] When K=M and L=N, the wavelength recombination unit 4401 can function as the path separation unit 4381 in Fig. 12. When K=N and L=M, the wavelength recombination unit 4401 can function as the path combination unit 4382 in Fig. 12.

[0088] FIG. 14 is a block diagram showing an example of the internal functional configuration of the wavelength recombining unit 4402. The wavelength recombining unit 4402 functions as a wavelength recombining means with K inputs and L outputs. Note that K and L are each a predetermined integer equal to or greater than 1. As shown in the figure, the wavelength recombining unit 4402 includes K optical splitters 44021 and L Kx1 WSSs 44022. The K optical splitters 44021 correspond to the K inputs of the wavelength recombining unit 4402, respectively. The input to one optical splitter 44021 may include L optical signals with different wavelengths. The optical splitter 44021 separates and distributes these L input optical signals, and passes each of the L optical signals to the Kx1 WSSs 44022. The L Kx1 WSSs 44022 correspond to the L outputs of the wavelength recombining unit 4402, respectively. Optical signals with different wavelengths are passed to one Kx1 WSS 44022 from each of K optical splitters 44021. The one Kx1 WSS 44022 mixes and outputs these K optical signals. With this configuration, the wavelength recombination unit 4402 recombines the K input optical signals and outputs L optical signals.

[0089] When K=M and L=N, the wavelength recombination unit 4402 can function as the path separation unit 4381 in Fig. 12. When K=N and L=M, the wavelength recombination unit 4402 can function as the path combination unit 4382 in Fig. 12.

[0090] As described above, in this embodiment, the path coupling / separation unit 438 is configured to include a path separation unit 4381 and a path coupling unit 4382. The path separation unit 4381 rearranges optical signals from multiple add ports so that the optical signals are grouped for each destination path. The path coupling unit 4382 rearranges optical signals received from multiple paths so that the optical signals are grouped for each destination drop port. The path separation unit 4381 is configured using an M-input, N-output wavelength recombination unit. The path coupling unit 4382 is configured using an N-input, M-output wavelength recombination unit. M is the number of the optical add / drop units, and N is the number of the paths. The wavelength recombination unit outputs L optical signals by performing recombination based on the wavelengths of the K input optical signals, and is configured so that an optical signal of a predetermined wavelength contained in any of the K input optical signals can be output as an optical signal among the L output optical signals. For example, K=M and L=N, or K=N and L=M.

[0091] Fifth Embodiment Next, a fifth embodiment of the present invention will be described. Note that the description of matters that have already been described in the previous embodiments may be omitted. Here, the description will focus on matters unique to this embodiment.

[0092] In the fourth embodiment described above, the path coupling / separation unit 438 includes both the path separation unit 4381 and the path coupling unit 4382. In the fourth embodiment, the same wavelength can be used for the uplink and downlink of each optical signal transmission / reception pair. In contrast, in the fifth embodiment, the path coupling / separation unit 438 can be configured with only one wavelength reconfiguration means, on the premise that the uplink and downlink of each optical signal transmission / reception pair is set to different wavelengths.

[0093] 15 is a block diagram showing a schematic functional configuration of an optical communication device according to a fifth embodiment. As shown in the figure, the optical communication device 5 includes an optical cross-connect unit 531, an optical add / drop unit 532, an optical add / drop unit 533, and a path coupling / separation unit 538. Note that optical amplifiers may be disposed at appropriate locations to compensate for losses incurred by optical signals when passing through each unit within the optical communication device 5.

[0094] 15, for example, the number of optical add / drop units is 2, and the number of paths is 2. However, in general, the number of optical add / drop units may be M (M is a predetermined integer greater than or equal to 1), and the number of paths may be N (N is a predetermined integer greater than or equal to 1).

[0095] The optical cross-connect unit 531 is configured to include a first demultiplexing unit 5311, a first multiplexing unit 5312, a second demultiplexing unit 5313, and a second multiplexing unit 5314. The optical add / drop unit 532 is configured to include a first add unit 5321 and a first drop unit 5322. The optical add / drop unit 533 is configured to include a second add unit 5331 and a second drop unit 5332.

[0096] Unlike the path coupling / separation unit 438 in the fourth embodiment (FIG. 12), the path coupling / separation unit 538 in this embodiment can be realized using one (M+N) input (M+N) output (M+N) x (M+N) wavelength recombination means. Note that the internal configuration of the (M+N) x (M+N) wavelength recombination means is as explained in the fourth embodiment with reference to FIGS. 13 and 14.

[0097] The configuration shown in Figure 15 is for the case where M = 2 and N = 2. That is, the optical signals from the first adding unit 5321, the second adding unit 5331, the first demultiplexing unit 5311, and the second demultiplexing unit 5313 are input to the direction coupling / separating unit 538. Each of the optical signals from the first adding unit 5321, the second adding unit 5331, the first demultiplexing unit 5311, and the second demultiplexing unit 5313 includes optical signals of multiple different wavelengths. The direction coupling / separating unit 538 rearranges these input optical signals. The direction coupling / separating unit 538 passes the rearranged optical signals to the first multiplexing unit 5312, the second multiplexing unit 5314, the first branching unit 5322, and the second branching unit 5332.

[0098] 15 , the optical signal added by the first adding unit 5321 includes optical signals of multiple wavelengths and is input to the path coupling / separating unit 538. The path coupling / separating unit 538 rearranges the optical signals. As a result of the rearrangement, a portion of the optical signal is passed to the first multiplexing unit 5312 and sent out from port 1A. Furthermore, another portion of the optical signal is passed to the second multiplexing unit 5314 and sent out from port 2A.

[0099] Similarly, the optical signals added by the second adding unit 5331 are rearranged in the path coupling / separating unit 538. As a result, a portion of the optical signal is passed to the first multiplexing unit 5312 and sent out from port 1A. In addition, another portion of the optical signal is passed to the second multiplexing unit 5314 and sent out from port 2A.

[0100] 15 , the optical signal received from the direction 1 side includes optical signals of multiple wavelengths, and is input to the direction coupling / separation unit 538 via the first demultiplexing unit 5311. The direction coupling / separation unit 538 rearranges the optical signals. As a result of the rearrangement, a portion of the optical signals is passed to the first branching unit 5322 and output from a branching port of the first branching unit 5322. The other portion of the optical signals rearranged by the direction coupling / separation unit 538 is passed to the second branching unit 5332 and output from a branching port of the second branching unit 5332.

[0101] The optical signal received from the direction 2 side contains optical signals of multiple wavelengths, and passes through the second demultiplexing unit 5313 and is recombined in the direction coupling / separation unit 538 in the same manner as above. As a result, a portion of the optical signal is passed to the first branching unit 5322 and output from a branching port of the first branching unit 5322. In addition, the other portion of the optical signal recombined by the direction coupling / separation unit 538 is passed to the second branching unit 5332 and output from a branching port of the second branching unit 5332.

[0102] As described above, in this embodiment, the optical signal added from a specific add port and sent to a specific path and the optical signal received from the specific path and output to a specific drop port corresponding to the specific add port have different wavelengths. The path coupling / separation unit 538 is configured using an (M+N) input (M+N) output wavelength recombiner, where M is the number of optical add / drop units and N is the number of paths. The wavelength recombiner outputs L optical signals by recombining based on the wavelengths of the K input optical signals, and is configured so that an optical signal of a predetermined wavelength contained in any optical signal among the K input optical signals can be output as an optical signal among the L output optical signals. Note that K=M+N and L=M+N may be used.

[0103] Sixth Embodiment Next, a sixth embodiment of the present invention will be described. Note that the following description may omit the matters already described in the previous embodiments. Here, the description will focus on matters unique to this embodiment.

[0104] The sixth embodiment is characterized by the provision of two redundant route units that function as route coupling / separation units. That is, port 3A, a transmitting port, is connected to port 3, a receiving port of the same route unit. Also, port 4A, a transmitting port, is connected to port 4, a receiving port of the same route unit.

[0105] 16 is a block diagram showing a schematic functional configuration of an optical communication device according to the sixth embodiment. As shown in the figure, the optical communication device 6 includes an optical cross-connect unit 631, an optical add / drop unit 632, and an optical add / drop unit 633.

[0106] The optical cross-connect unit 631 is composed of a first demultiplexing unit 6311, a first multiplexing unit 6312, a second demultiplexing unit 6313, a second multiplexing unit 6314, a third multiplexing unit 6381, a third demultiplexing unit 6382, a fourth multiplexing unit 6383, and a fourth demultiplexing unit 6384.

[0107] The optical add / drop section 632 includes a first add section 6321 and a first drop section 6322. The optical add / drop section 633 includes a second add section 6331 and a second drop section 6332.

[0108] Of the functions constituting the optical cross-connect unit 631, the combined function of the third multiplexing unit 6381, the third demultiplexing unit 6382, the fourth multiplexing unit 6383, and the fourth demultiplexing unit 6384 functions as a path coupling / separation unit 638. In other words, this path coupling / separation unit 638 separates optical signals to be sent to paths for each path, and combines optical signals received from multiple paths to branch them from a specific port.

[0109] In the configuration of the optical communication device 6 shown in FIG. 16, optical amplifiers may be placed at appropriate locations to compensate for the loss that the optical signal experiences when passing through each functional unit.

[0110] In addition, in the configuration of the optical communication device 6 shown in FIG. 16, the paths indicated by the broken lines are not used.

[0111] FIG. 17 is a schematic diagram illustrating the paths of optical signals when an added optical signal is separated and sent out for each path in the optical communication device 6 of this embodiment. Two signals with different wavelengths are input through one add port of the first add unit 6321. These two signals are referred to as signal 13 and signal 14. Signal 13 and signal 14 are passed from the first add unit 6321 to the third multiplexer 6381 via route R131. Signal 13 and signal 14 are passed from the third multiplexer 6381 to the third demultiplexer 6382 via route R132. The third demultiplexer 6382 demultiplexes signal 13 and signal 14. Signal 13 is passed from the third demultiplexer 6382 to the first multiplexer 6312 via route R133. The first multiplexer 6312 sends signal 13 out from port 1A on the path 1 side. On the other hand, signal 14 is passed from third demultiplexing unit 6382 through route R134 to second multiplexing unit 6314. Second multiplexing unit 6314 sends signal 14 from port 2A on the direction 2 side.

[0112] The same applies to the case where an optical signal is input from the add port of the second add unit 6331. That is, the optical signal is passed to the third multiplexer 6381 and demultiplexed in the third demultiplexer 6382. One of these demultiplexed signals is passed to the first multiplexer 6312 and sent out from port 1A on the path 1 side. The other demultiplexed signal is passed to the second multiplexer 6314 and sent out from port 2A on the path 2 side.

[0113] That is, optical signals of multiple wavelengths input from one add port of the first add unit 6321 or the second add unit 6331 are separated in the third multiplexing unit 6381 and the third demultiplexing unit 6382, and are sent out from port 1A on the side of path 1 and port 2A on the side of path 2, respectively. Here, the third multiplexing unit 6381 and the third demultiplexing unit 6382 together can be regarded as a path separating unit.

[0114] FIG. 18 is a schematic diagram showing the paths of optical signals when optical signals received from the path 1 side and the path 2 side are output from the branch ports of the first branching unit 6322 of the optical communication device 6. Two signals with different wavelengths are received at port 1 on the path 1 side and port 2 on the path 2 side. These two signals are referred to as signal 15 and signal 16, respectively. Signals 15 and 16 are signals to be branched in the optical communication device 6. Signal 15 input to the first branching unit 6311 is passed to the fourth multiplexing unit 6383 via route R135. Signal 16 input to the second branching unit 6313 is passed to the fourth multiplexing unit 6383 via route R136. The fourth multiplexing unit 6383 multiplexes these signals 15 and 16. The combined signals 15 and 16 are passed to the fourth branching unit 6384 via route R137. Signals 15 and 16 are passed from fourth demultiplexing unit 6384 through route R138 to first branching unit 6322. Signals 15 and 16 are then output from one branch port that first branching unit 6322 has.

[0115] The same applies to the case where an optical signal is output from a branch port of the second branching unit 6332. That is, the optical signal is received from each of the path 1 side and the path 2 side, passed to the fourth multiplexing unit 6383, and demultiplexed in the fourth demultiplexing unit 6384. These signals are passed to the second branching unit 6332 and output from one branch port that the second branching unit 6332 has.

[0116] That is, optical signals of different wavelengths received at port 1 on the path 1 side and port 2 on the path 2 side, respectively, are combined in the fourth multiplexing unit 6383 and the fourth demultiplexing unit 6384, and output from one branch port of the first branching unit 6322 or the second branching unit 6332. Here, the fourth multiplexing unit 6383 and the fourth demultiplexing unit 6384 together can be regarded as a path combining unit.

[0117] As described above, in this embodiment, the path separation unit multiplexes optical signals from multiple add ports and demultiplexes the multiplexed optical signals so that they are collected for each destination path. Also, the path coupling unit multiplexes optical signals received from multiple paths and demultiplexes the multiplexed optical signals so that they are collected for each destination branch port.

[0118] [Seventh Embodiment] Next, a seventh embodiment of the present invention will be described. Note that the following description may omit the matters already described in the previous embodiments. Here, the description will focus on matters unique to this embodiment.

[0119] The seventh embodiment is characterized in that two extra route units are provided and function as route coupling / separation units. In this embodiment, port 3A, which is a transmitting port, is connected to port 4, which is a receiving port. Furthermore, port 4A, which is a transmitting port, is connected to port 3, which is a receiving port.

[0120] 19 is a block diagram showing a schematic functional configuration of an optical communication device according to the seventh embodiment. As shown in the figure, the optical communication device 7 includes an optical cross-connect unit 731, an optical add / drop unit 732, and an optical add / drop unit 733.

[0121] The optical cross-connect unit 731 is configured to include a first demultiplexing unit 7311, a first multiplexing unit 7312, a second demultiplexing unit 7313, a second multiplexing unit 7314, a third multiplexing unit 7381, a third demultiplexing unit 7382, a fourth multiplexing unit 7383, and a fourth demultiplexing unit 7384. The optical add / drop unit 732 is configured to include a first add unit 7321 and a first drop unit 7322. The optical add / drop unit 733 is configured to include a second add unit 7331 and a second drop unit 7332.

[0122] Of the functions constituting the optical cross-connect unit 731, the combined function of the third multiplexing unit 7381, the third demultiplexing unit 7382, the fourth multiplexing unit 7383, and the fourth demultiplexing unit 7384 functions as a path coupling / separation unit 738. In other words, this path coupling / separation unit 738 separates optical signals to be sent to paths for each path, and combines optical signals received from multiple paths to branch them from a specific port.

[0123] As shown in the figure, port 3A is connected to port 4. As a result, the optical signal output from the third multiplexing unit 7381 is input to the fourth demultiplexing unit 7384. In addition, port 4A is connected to port 3. As a result, the optical signal output from the fourth multiplexing unit 7383 is input to the third demultiplexing unit 7382.

[0124] In the configuration of the optical communication device 7 shown in FIG. 19, optical amplifiers may be placed at appropriate locations to compensate for the loss that the optical signal experiences when passing through each functional unit.

[0125] In addition, in the configuration of the optical communication device 7 shown in FIG. 19, the paths indicated by the broken lines are not used.

[0126] FIG. 20 is a schematic diagram illustrating the paths of optical signals when an added optical signal is separated and transmitted for each path in the optical communication device 7 of this embodiment. Two signals with different wavelengths are input from one add port of the first add unit 7321. These two signals are referred to as signal 17 and signal 18. Signals 17 and 18 are passed from the first add unit 7321 to the fourth multiplexer 7383 via route R141. Signals 17 and 18 are passed from the fourth multiplexer 7383 to the third demultiplexer 7382 via route R142. The third demultiplexer 7382 demultiplexes signal 17 and signal 18. Signal 17 is passed from the third demultiplexer 7382 to the first multiplexer 7312 via route R143. The first multiplexer 7312 transmits signal 17 from port 1A on the path 1 side. On the other hand, signal 18 is passed from third demultiplexer 7382 through route R144 to second multiplexer 7314. Second multiplexer 7314 sends signal 18 from port 2A on the route 2 side.

[0127] The same applies to the case where an optical signal is input from the add port of the second add unit 7331. That is, the optical signal is passed to the fourth multiplexer 7383 and demultiplexed in the third demultiplexer 7382. One of these demultiplexed signals is passed to the first multiplexer 7312 and sent out from port 1A on the path 1 side. The other demultiplexed signal is passed to the second multiplexer 7314 and sent out from port 2A on the path 2 side.

[0128] That is, optical signals of multiple wavelengths input from one add port of the first add unit 7321 or the second add unit 7331 are separated in the fourth multiplexer 7383 and the third demultiplexer 7382 and are sent out from port 1A on the path 1 side and port 2A on the path 2 side, respectively. Here, the fourth multiplexer 7383 and the third demultiplexer 7382 together can be regarded as a path separation unit.

[0129] FIG. 21 is a schematic diagram showing the paths of optical signals received from the path 1 side and the path 2 side when they are output from the branch ports of the first branching unit 7322 of the optical communication device 7. Two signals with different wavelengths are received at port 1 on the path 1 side and port 2 on the path 2 side. These two signals are referred to as signal 19 and signal 20, respectively. Signals 19 and 20 are signals to be branched in the optical communication device 7. Signal 19 input to the first demultiplexing unit 7311 is passed to the third multiplexing unit 7381 via route R145. Signal 20 input to the second demultiplexing unit 7313 is passed to the third multiplexing unit 7381 via route R146. The third multiplexing unit 7381 multiplexes these signals 19 and 20. The combined signals 19 and 20 are passed to the fourth demultiplexing unit 7384 via route R147. Signals 19 and 20 are passed from fourth demultiplexer 7384 through route R148 to first branching unit 7322. Signals 19 and 20 are then output from one branch port that first branching unit 7322 has.

[0130] The same applies to the case where an optical signal is output from a branch port of the second branching unit 7332. That is, the optical signal is received from each of the path 1 side and the path 2 side, passed to the third multiplexing unit 7381, and demultiplexed in the fourth demultiplexing unit 7384. These signals are passed to the second branching unit 7332 and output from one branching port that the second branching unit 7332 has.

[0131] That is, optical signals of different wavelengths received at port 1 on the path 1 side and port 2 on the path 2 side are combined in the third multiplexer 7381 and fourth demultiplexer 7384 and output from one branch port of the first brancher 7322 or the second brancher 7332. Here, the third multiplexer 7381 and the fourth demultiplexer 7384 together can be regarded as a path combination unit.

[0132] As described above, in this embodiment, the path separation unit multiplexes optical signals from multiple add ports and demultiplexes the multiplexed optical signals so that they are collected for each destination path. Also, the path coupling unit multiplexes optical signals received from multiple paths and demultiplexes the multiplexed optical signals so that they are collected for each destination branch port.

[0133] Eighth Embodiment Next, an eighth embodiment of the present invention will be described. Note that the following description may omit matters that have already been described in the previous embodiments. Here, the description will focus on matters unique to this embodiment.

[0134] The eighth embodiment is characterized in that the optical path coupling / separation unit (838) has an additional function of performing a loopback function between the drop port and the add port of the optical add / drop units (832, 833). That is, with the configuration described below, an optical signal input to the first add unit 8321 can be looped back and output from the second add unit 8332. Also, an optical signal input to the second add unit 8331 can be looped back and output from the first add unit 8322.

[0135] 22 is a block diagram showing a schematic functional configuration of an optical communication device according to the eighth embodiment. As shown in the figure, the optical communication device 8 includes an optical cross-connect unit 831, an optical add / drop unit 832, an optical add / drop unit 833, and a path coupling / separation unit 838.

[0136] The optical cross-connect unit 831 is configured to include a first demultiplexing unit 8311, a first multiplexing unit 8312, a second demultiplexing unit 8313, and a second multiplexing unit 8314. The optical add / drop unit 832 is configured to include a first add unit 8321 and a first drop unit 8322. The optical add / drop unit 833 is configured to include a second add unit 8331 and a second drop unit 8332.

[0137] The path coupling / separating unit 838 includes a third multiplexing unit 8381 , a third demultiplexing unit 8382 , a fourth multiplexing unit 8383 , and a fourth demultiplexing unit 8384 .

[0138] A feature of this embodiment is that the optical cross-connect unit 831 is configured as follows. That is, an optical signal can be passed from the first adding unit 8321 to the fourth multiplexing unit 8383. An optical signal can also be passed from the second adding unit 8331 to the fourth multiplexing unit 8383. An optical signal can also be passed from the third demultiplexing unit 8382 to the first branching unit 8322. An optical signal can also be passed from the third demultiplexing unit 8382 to the second branching unit 8332. This makes it possible to loop back an optical signal between the optical add-drop unit 832 and the optical add-drop unit 833, as will be described below with reference to FIG. 23 .

[0139] Among the add ports of the optical add / drop unit 832 or 833, an add port used for the above-mentioned return communication may be called a "turn-back add port." Furthermore, among the branch ports of the optical add / drop unit 832 or 833, a branch port used for the above-mentioned return communication may be called a "turn-back branch port." In this embodiment, at least some of the multiple add ports operate as turn-back add ports. Multiple turn-back add ports may be present. Furthermore, at least some of the multiple branch ports operate as turn-back branch ports. Multiple turn-back branch ports may exist simultaneously. One turn-back add port and one turn-back branch port may be associated as a pair. Whether each add port is a turn-back add port or whether each branch port is a turn-back branch port can be changed by the settings of the optical add / drop unit and the optical path coupling / decoupling unit, and by the setting of the wavelength of the input optical signal.

[0140] The folding configuration of this embodiment may be implemented in combination with other embodiments (first, second, third, fourth, fifth, sixth, seventh, and ninth embodiments).

[0141] FIG. 23 is a schematic diagram for explaining the path of an optical signal when the optical signal is turned back between the optical add / drop unit 832 and the optical add / drop unit 833 in the optical communication device 8 of this embodiment.

[0142] An optical signal is input from one port of the first adding unit 8321. This signal is referred to as signal 21. Signal 21 may include signals of multiple wavelengths. Signal 21 input to the first adding unit 8321 is passed to the third multiplexing unit 8381 via route R151. Signal 21 is passed from the third multiplexing unit 8381 to the third demultiplexing unit 8382 via route R152. Furthermore, signal 21 is passed from the third demultiplexing unit 8382 to the second branching unit 8332 via route R153. Then, signal 21 is output from one branching port of the second branching unit 8332.

[0143] An optical signal is input from one port of the second adding unit 8331. This signal is referred to as signal 22. Signal 22 may include signals of multiple wavelengths. Signal 22 input to the second adding unit 8331 is passed to the fourth multiplexing unit 8383 via route R154. Signal 22 is passed from the fourth multiplexing unit 8383 to the fourth demultiplexing unit 8384 via route R155. Furthermore, signal 22 is passed from the fourth demultiplexing unit 8384 to the first branching unit 8322 via route R156. Then, signal 22 is output from one branching port of the first branching unit 8322.

[0144] An optical signal input to one add port of the first adding unit 8321 may be passed to the fourth multiplexing unit 8383, further passed to the fourth demultiplexing unit 8384, further passed to the first branching unit 8322, and output from one branching port of the first branching unit 8322. Also, an optical signal input to one add port of the second adding unit 8331 may be passed to the third multiplexing unit 8381, further passed to the third demultiplexing unit 8382, further passed to the second branching unit 8332, and output from one branching port of the second branching unit 8332.

[0145] That is, in this embodiment, at least some of the add ports are return add ports for folding back optical signals. Also, at least some of the drop ports are return drop ports for folding back optical signals. The optical cross-connect unit 831 passes optical signals added from specific add ports to the path coupling / separation unit 838. The path coupling / separation unit 838 combines the optical signals from the specific add ports passed from the optical cross-connect unit 831 so as to become part of the optical signal to be output from a specific drop port. The optical cross-connect unit 831 receives the optical signal to be output from the specific drop port from the path coupling / separation unit 838 and passes it to the optical drop add unit (832 or 833) that has the specific drop port. Note that there may be multiple pairs of a specific add port and a corresponding specific drop port.

[0146] The configuration of this embodiment makes it possible to loop back an optical signal between the add port and the drop port on the optical add / drop unit side.

[0147] [Ninth Embodiment] Next, a ninth embodiment of the present invention will be described. Note that the matters already explained in the previous embodiments may not be explained below. Here, the explanation will focus on matters unique to this embodiment. The ninth embodiment is an optical communication system including an optical communication device.

[0148] 24 is a block diagram showing a schematic functional configuration of an optical communication system according to the ninth embodiment. As shown in the figure, the optical communication system 91 includes an optical communication device 9, optical splitters 941 and 942, and optical transceivers 943, 944, 945, and 946 (plurality of optical transceivers).

[0149] The optical communication device 9 includes an optical cross-connect unit 931, an optical add / drop unit 932, an optical add / drop unit 933, and a path coupling / separation unit 938. The optical communication device 9 may be any one of the optical communication devices 1, 2, 3, 4, 5, 6, 7, and 8 described in the first to eighth embodiments.

[0150] The optical splitters 941 and 942 are devices that distribute / aggregate optical signals. Note that instead of the optical splitters, wavelength division multiplexers or WSSs may be used to provide the same functions.

[0151] Each of the optical transceivers 943, 944, 945, and 946 is a device that transmits and receives optical signals.

[0152] 24 , an optical splitter 941 aggregates optical signals transmitted from optical transceivers 943, 944, 945, and 946 and transmits the aggregated optical signals to one of the add ports of an optical add / drop unit 932 in the optical communication device 9. The optical splitter 942 distributes an optical signal transmitted from one of the add ports of the optical add / drop unit 932 in the optical communication device 9 to the optical transceivers 943, 944, 945, and 946. Optical fibers transmit optical signals between the optical splitter 941 and the add port of the optical add / drop unit 932, and between the drop port of the optical add / drop unit 932 and the optical splitter 942.

[0153] The optical splitters 941 and 942 and the optical transceivers 943, 944, 945, and 946 may be collectively referred to as a multi-wavelength optical signal transmitting and receiving means.

[0154] Optical fibers are also present between the optical splitters 941 and 942 and the optical transceivers 943, 944, 945, and 946. Furthermore, the optical transceivers 943, 944, 945, and 946 may be located in different locations.

[0155] In the optical communication system 91 configured as described above, the optical communication device 9 can add an optical signal transmitted from at least one of the optical transceivers 943, 944, 945, and 946 to a path. In addition, at least one of the optical transceivers 943, 944, 945, and 946 can receive an optical signal dropped from a path by the optical communication device 9.

[0156] That is, in this embodiment, an optical signal transmitted from at least one of the optical transceivers 943, 944, 945, and 946 can be added to multiple paths (e.g., path 1 and path 2) via a single add port of the optical add / drop unit 932. Furthermore, an optical signal dropped from multiple paths (e.g., path 1 and path 2) can be received by at least one of the optical transceivers 943, 944, 945, and 946 via a single drop port of the optical add / drop unit 932.

[0157] FIG. 25 is a block diagram showing an example of the internal configuration of a computer when at least some of the functions of any of the optical communication devices 1, 2, 3, 4, 5, 6, 7, 8, and 9 described in the first to ninth embodiments are realized using a computer. As shown in the figure, the computer includes a central processing unit 1901, a RAM 1902, an input / output port 1903, input / output devices 1904 and 1905, and a bus 1906. The computer itself can be realized using existing technology. The central processing unit 1901 executes instructions contained in a program read from the RAM 1902, etc. In accordance with each instruction, the central processing unit 1901 writes data to the RAM 1902, reads data from the RAM 1902, and performs arithmetic and logical operations. The RAM 1902 stores data and programs. Each element included in the RAM 1902 has an address and can be accessed using the address. Note that RAM is an abbreviation for "random access memory." The input / output port 1903 is a port through which the central processing unit 1901 exchanges data with external input / output devices. The input / output devices 1904 and 1905 exchange data with the central processing unit 1901 via the input / output port 1903. The bus 1906 is a common communication path used within the computer. For example, the central processing unit 1901 reads and writes data from the RAM 1902 via the bus 1906. Also, for example, the central processing unit 1901 accesses the input / output port 1903 via the bus 1906.

[0158] The input / output devices 1904 and 1905 are, for example, control circuits associated with the WSS and MCS shown below. That is, any of the optical communication devices 1, 2, 3, 4, 5, 6, 7, 8, and 9 is equipped with a central processing unit 1901 (CPU). This central processing unit 1901 may control the settings of a multiplexing unit (e.g., WSS), demultiplexing unit (e.g., WSS), branching unit (e.g., MCS, Multicast Switch), and insertion unit (e.g., MCS). In some cases, the multiplexing unit and demultiplexing unit are configured as a single box and equipped with a single central processing unit. Similarly, in some cases, the branching unit and insertion unit are configured as a single box and equipped with a single central processing unit.

[0159] [Modifications] In the above-described embodiments, the block diagrams shown in Figures 1 to 12 and 15 to 24 illustrate configurations of optical communication devices in which the number of optical add / drop units (M) is 2 and the number of paths (N) is 2. However, in each embodiment, M is not limited to 2 or N is not limited to 2. That is, the number of optical add / drop units (M) may be 1 or a predetermined integer equal to or greater than 3. Furthermore, the number of paths (N) may be 1 or a predetermined integer equal to or greater than 3.

[0160] The optical communication devices described in the first to ninth embodiments execute the following communication method. In this communication method, the optical communication device adds a first optical signal to a path and drops a second optical signal from the path. Here, for convenience, the optical signal added from the add port is called a "first optical signal." Also, for convenience, the optical signal dropped from the drop port is called a "second optical signal."

[0161] As one step in the communication method, the first optical signal to be inserted into a path is input from an add port of an optical drop-add unit, the first optical signal input from the add port is passed to a path coupling / separation unit by the optical cross-connect unit, the path coupling / separation unit receives the first optical signal from the optical cross-connect unit and separates it by path, the path coupling / separation unit passes the separated first optical signal to the optical cross-connect unit by path, and the optical cross-connect unit sends the separated first optical signal toward a target path. Furthermore, as one process, the optical cross-connect unit receives the second optical signal to be branched from a path and passes it to the path coupling / separation unit, the path coupling / separation unit receives the second optical signals received from a plurality of paths from the optical cross-connect unit and combines them for each branch port of the optical branching / insertion unit, the optical cross-connect unit receives the second optical signals combined for each branch port from the path coupling / separation unit and passes them to the optical branching / insertion unit having the target branch port, and the second optical signal received by the optical branching / insertion unit is output from the target branch port.

[0162] As described above, according to any of the first to ninth embodiments, when multiple optical signals with different wavelengths are added from the same add port of an optical add-drop unit, it is possible to send each optical signal to a different path. Furthermore, it is possible to drop multiple optical signals with different wavelengths from different paths to the same drop port of the optical add-drop unit. At the same time, it is possible to obtain CDC, i.e., colorless (wavelength independent), directionless (direction independent), and contentionless (contention free) characteristics.

[0163] The present invention can be used in, for example, communications using optical signals, although the scope of use of the present invention is not limited to this.

[0164] 1, 2, 3, 4, 5, 6, 7, 8, 9 Optical communication device 91 Optical communication system 131 Optical cross connect unit 132, 133 Optical add / drop unit 138 Path coupling / separation unit 231 Optical cross connect unit 232, 233 Optical add / drop unit 238 Path coupling / separation unit 331 Optical cross connect unit 332, 333 Optical add / drop unit 338 Path coupling / separation unit 431 Optical cross connect unit 432, 433 Optical add / drop unit 438 Path coupling / separation unit 531 Optical cross connect unit 532, 533 Optical add / drop unit 538 Path coupling / separation unit 631 Optical cross connect unit 632, 633 Optical add / drop unit 638 Path coupling / separation unit 731 Optical cross connect unit 732, 733 Optical add / drop units 738 Path coupling / separation unit 831 Optical cross connect unit 832, 833 Optical add / drop units 838 Path coupling / separation unit 931 Optical cross connect unit 932, 933 Optical add / drop units 938 Path coupling / separation unit 941, 942 Optical splitters 943, 944, 945, 946 Optical transceiver 1901 Central processing unit 1902 RAM 1903 Input / output ports 1904, 1905 Input / output devices 1906 Bus 2311 First demultiplexing unit 2312 First multiplexing unit 2313 Second demultiplexing unit 2314 Second multiplexing unit 2321 First insertion unit 2322 First branching unit 2331 Second insertion unit 2332 Second branching unit 2381 Third multiplexing unit 2382 Third demultiplexing unit 2383 Fourth multiplexing unit 2384 Fourth demultiplexing unit 3311 First demultiplexing unit 3312 First multiplexing unit 3313 Second demultiplexing unit 3314 Second multiplexing unit 3321 First insertion unit 3322 First branching unit 3331 Second insertion unit 3332 Second branching unit 3381 Third multiplexing unit 3382 Third demultiplexing unit 4311 First demultiplexing unit 4312 First multiplexing unit 4313 Second demultiplexing unit 4314 Second multiplexing unit 4321 First insertion unit 4322 First branching unit 4331 Second insertion unit 4332 Second branching unit 4381 Direction separation unit 4382 Direction coupling unit 4401,4402 wavelength recombination section 5311 first demultiplexing section 5312 first multiplexing section 5313 second demultiplexing section 5314 second multiplexing section 5321 first insertion section 5322 first branching section 5331 second insertion section 5332 second branching section 6311 first demultiplexing section 6312 first multiplexing section 6313 second demultiplexing section 6314 second multiplexing section 6321 first insertion section 6322 first branching section 6331 second insertion section 6332 second branching section 6381 third multiplexing section 6382 third demultiplexing section 6383 fourth multiplexing section 6384 fourth demultiplexing section 7311 first demultiplexing section 7312 first multiplexing section 7313 second demultiplexing section 7314 second multiplexing section 7321 First insertion section 7322 First branching section 7331 Second insertion section 7332 Second branching section 7381 Third multiplexing section 7382 Third demultiplexing section 7383 Fourth multiplexing section 7384 Fourth demultiplexing section 8311 First demultiplexing section 8312 First multiplexing section 8313 Second demultiplexing section 8314 Second multiplexing section 8321 First insertion section 8322 First branching section 8331 Second insertion section 8332 Second branching section 8381 Third multiplexing section 8382 Third demultiplexing section 8383 Fourth multiplexing section 8384 Fourth demultiplexing section 44011 1xL WSS 44012 Optical coupler 44021 Optical splitter 44022 Kx1 WSS,

Claims

1. An optical communication device comprising: an optical add-drop unit having an add port for adding an optical signal and a drop port for dropping an optical signal; an optical cross-connect unit that connects an optical signal added from said add port to a route, connects an optical signal input from said route to another route, and connects said optical signal input from said route to said optical add-drop unit so that it can be output from said drop port; and a path coupling / separation unit that receives multi-wavelength optical signals added from said add port of said optical add-drop unit from said optical cross-connect unit, separates them by route, and combines each separated optical signal by destination route and outputs it to said optical cross-connect unit, and also receives optical signals input from a plurality of said routes from said optical cross-connect unit, combines them for each drop port, and outputs them to said optical cross-connect unit.

2. The optical communication device according to claim 1, wherein the path coupling / separation unit comprises: a path separation unit that multiplexes optical signals from a plurality of the add ports and demultiplexes the multiplexed optical signals so that they are collected for each destination path; and a path coupling unit that multiplexes optical signals received from a plurality of the paths and demultiplexes the multiplexed optical signals so that they are collected for each target branch port.

3. An optical communication device as claimed in claim 1, wherein an optical signal inserted from a specific add port and sent to a specific route, and an optical signal received from the specific route and output to a specific branch port corresponding to the specific add port, have mutually different wavelengths, and the route coupling and separation unit comprises: a multiplexing unit that combines each of the optical signals inserted from the multiple add ports with each of the optical signals received from the multiple routes; and a demultiplexing unit that demultiplexes the optical signals based on the optical signals combined by the multiplexing unit so that they are grouped for each destination route and so that they are grouped for each target branch port.

4. The optical communication device according to claim 1, wherein the path coupling / separation unit comprises: a path separation unit that rearranges optical signals from a plurality of add ports so that the optical signals are grouped for each destination path; and a path coupling unit that rearranges optical signals received from a plurality of paths so that the optical signals are grouped for each target drop port; wherein the path separation unit is configured using an M-input N-output wavelength rearrangement unit; the path coupling unit is configured using an N-input M-output wavelength rearrangement unit, where M is the number of the optical add / drop units and N is the number of the paths; and wherein the wavelength rearrangement unit outputs L optical signals by rearranging the signals based on the wavelengths of the K input optical signals, and wherein an optical signal of a predetermined wavelength contained in any of the K input optical signals can be output as an optical signal of the L output optical signals.

5. An optical communication device as described in claim 1, wherein an optical signal that is added from a specific add port and sent to a specific path, and an optical signal that is received from the specific path and output to a specific drop port corresponding to the specific add port, have mutually different wavelengths, the path coupling / separation unit is configured using an (M+N) input (M+N) output wavelength recombination unit, M is the number of the optical drop / add units, N is the number of the paths, the wavelength recombination unit outputs L optical signals by recombining based on the wavelengths of the K input optical signals, and an optical signal of a predetermined wavelength contained in any optical signal of the K input optical signals is configured to be output as an optical signal of the L output optical signals.

6. The optical communication device according to claim 1, wherein the optical cross-connect unit passes an optical signal added from a specific one of the add ports to the path coupling / separation unit, and the path coupling / separation unit combines the optical signal added from the specific one of the add ports passed from the optical cross-connect unit so as to become part of an optical signal output from a specific one of the drop ports.

7. An optical communication system comprising: an optical communication device according to any one of claims 1 to 6; and one or more optical transceivers that transmit optical signals to be sent to the plurality of paths to the add port of the optical add / drop unit of the optical communication device, and receive optical signals received from the plurality of paths from the drop port of the optical add / drop unit of the optical communication device.

8. A communication method in which an optical communication device adds a first optical signal to a path and drops a second optical signal from a path, comprising: inputting the first optical signal to be added to a path from an add port of an optical drop-add unit; the optical cross-connect unit passes the first optical signal input from the add port to a path coupling / separation unit; the path coupling / separation unit receives the first optical signal from the optical cross-connect unit and separates it for each path; the path coupling / separation unit passes the separated first optical signal to the optical cross-connect unit for each path; and the optical cross-connect unit sends out the separated first optical signal toward a target path; a communication method in which the optical cross-connect unit receives the second optical signal to be branched from a path and passes it to the path coupling / separation unit, the path coupling / separation unit receives the second optical signals received from a plurality of paths from the optical cross-connect unit and combines them for each branch port of the optical add-drop unit, the optical cross-connect unit receives the second optical signal combined for each branch port from the path coupling / separation unit and passes it to the optical add-drop unit having a target branch port, and the second optical signal received by the optical add-drop unit is output from the target branch port.

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