Optical transmission device

Abstract

Provided is an optical transmission device capable of acheiving both a configuration in which a plurality of optical amplifiers having different amplifiable wavelength ranges can be easily applied, and a configuration in which route control in core wire units of optical fibers can be performed. An optical transmission device according to the present disclosure comprises: a first wavelength group splitter that splits an input signal into optical signals of a wavelength group; an optical amplifier that amplifies the optical signals of the wavelength group; an optical signal reception function unit and an optical signal transmission function unit that input and output desired optical signals to own nodes thereof; an optical switch function unit that is capable of selecting whether to connect the optical signals generated by the optical signal transmission function unit such that it is possible to select whether to propagate the amplified optical signals of the wavelength group to the optical signal reception function unit side; a first wavelength group multiplexer that multiplexes desired optical signals which have been generated and / or the optical signals of the wavelength group, the optical signals being amplified for each input / output port; and a first optical switch that is capable of selecting an output path of the optical signals output from respective wavelength group multiplexers.

Description

Optical Transmission Equipment

[0001] The present disclosure relates to an optical transmission device.

[0002] With the spread of the Internet, the demand for data communication networks is rapidly increasing. To meet this rapidly increasing demand, optical communication networks that can transmit large amounts of data with low power consumption are being widely constructed.

[0003] In addition to the function of directly connecting two points, such an optical communication network can also flexibly set routes by using optical transmission equipment that employs optical switches.

[0004] In recent years, an optical transmission device configuration called CDC-ROADM (Colorless, Directionless, Contentionless-Reconfigurable Optical Add Drop Multiplexer) has been widely used as an example of an optical transmission device that uses such an optical switch (see, for example, Non-Patent Document 1). Optical transmission devices in the form of CDC-ROADM are a method for efficient data communication in multi-directional networks such as multi-ring and mesh networks, and are characterized by their effectiveness in efficient management of communication resources.

[0005] Fig. 1 is a diagram showing a conceptual configuration of an optical transmission device 100 having the form of a conventional CDC-ROADM. As shown in Fig. 1, the optical transmission device 100 includes a 1-input, L-output wavelength selective switch (hereinafter referred to as WSS) 110, an L-input, 1-output WSS 120, an M-input, N-output receiver transponder aggregator (hereinafter referred to as TPA) 130, and an N-input, M-output transmitter TPA 140. Fig. 1 depicts a configuration in which M WSSs 110, 110-1 to 110-M, and M WSSs 120, 1210 to 120-M, are arranged.

[0006] Of the output terminals of the L number of WSSs 110-1 to 110-M, the output terminal of M-1 is connected to the input terminal of M-1 WSSs 120 having a branch number different from its own branch number. For example, the output terminal of M-1 of WSS 110-1 is connected to the input terminal of WSSs 120 (WSSs 120-2 to 120-M) other than WSS 120-1. In other words, the connection relationship between the output terminal of WSS 110 and the input terminal of WSS 120 is configured such that the wiring between WSSs 110 and WSS 120 with the same branch number, which forms the return path, is deleted from a fully meshed wiring state.

[0007] Of the output terminals of the L number of WSSs 110-1 to 110-M, one output terminal is connected to the input terminal of the receiver TPA 130. Also, of the input terminals of the L number of WSSs 1210 to 120-M, one input terminal is connected to the output terminal of the transmitter TPA 140.

[0008] The 1-input, L-output WSSs 110-1 to 110-M have an optical switching function that allows users to select an output terminal for each wavelength of the input wavelength-multiplexed signal and output the wavelength-multiplexed signal. Furthermore, the L-input, 1-output WSSs 1210 to 120-M have a function to multiplex the input optical signals to form the output wavelength-multiplexed signal. The receiver TPA 130, for example, is a multicast switch configured by fully meshing M 1-input, N-output optical splitters 131 and N M-input, 1-output optical switches 132, and can output an optical signal input to any of the input terminals from any output terminal. The transmitter TPA 140, for example, is a multicast switch configured by fully meshing N 1-input, M-output optical switches 141 and M N-input, 1-output optical couplers 142, and can wavelength-multiplex and output an optical signal input from an input terminal as needed from any output terminal.

[0009] In the optical transmission device 100 configured in this manner, the optical signal input from the input terminal of the N-input / M-output transmitter TPA 140 may be of any wavelength and can be output from any of the WSSs 120-1 to 120-M. Optical signals of the same wavelength can be input to different input terminals of the transmitter TPA 140 under the condition that they are not output from the same WSS 120-1 to 120-M. Furthermore, the optical signal output from the output terminal of the M-input / N-output receiver TPA 130 can be an optical signal input from any of the WSSs 110-1 to 110-M. In other words, the optical transmission device 100 has functions known as colorless (capable of outputting any wavelength), directionless (capable of outputting to any route), and contentionless (no wavelength or route collisions).

[0010] As another example of an optical transmission device that uses an optical switch, in order to simplify the device configuration of the optical transmission device, a configuration is known in which the path switching unit is not only per signal wavelength, but also a combination of path switching per wavelength group consisting of multiple signal wavelengths (see, for example, non-patent document 2).

[0011] 2 is a diagram showing a conceptual configuration of a conventional optical transmission device 200. As described above, in order to simplify the device configuration, the optical transmission device 200 has a configuration in which path switching is performed not only in units of signal wavelengths but also in units of wavelength groups each consisting of a plurality of signal wavelengths. 2, the optical transmission device 200 includes P 1-input, Q-output wavelength group demultiplexers 210-1 through 210-P, P Q-input, 1-output wavelength group multiplexers 220-1 through 220-P, Q (P+R)-input, (P+R)-output optical switches 230-1 through 230-Q provided for each wavelength group, R 1-input, S-output wavelength demultiplexers 240-q-1 through 240-q-R provided for the qth wavelength group optical signals (q is an integer between 1 and Q) output from the optical switches 230-1 through 230-Q, R S-input, 1-output wavelength multiplexers 250-q-1 through 250-q-R provided for the qth wavelength group, and Q×S 2R-input, 2R-output optical switches 260-1 through 260-S provided for each wavelength. Note that FIG. 2 shows an example in which P=2, Q=5, S=8, R=2, and q=1. Also in FIG. 2, the number of wavelengths of optical signals per fiber propagating through each transmission path (which may be an optical fiber) is depicted in the balloon blocks.

[0012] An optical signal multiplexed with Q×S (5×8=40 in FIG. 2 ) different wavelengths is input from the outside to one of wavelength group demultiplexers 210-1 to 210-P (wavelength group demultiplexers 210-1 to 210-2 in FIG. 2 ) as an input optical signal to optical transmission device 200. Each of wavelength group demultiplexers 210-1 to 210-2 demultiplexes the optical signal multiplexed with Q×S=40 different wavelengths into optical signals of Q=5 different wavelength groups into which S=8 different wavelengths are multiplexed, and outputs the demultiplexed optical signals of Q=5 different wavelength groups from different ports. That is, the input signal light input to optical transmission device 200 is input to one of wavelength group demultiplexers 210-1 to 210-2 and demultiplexed into optical signals multiplexed with S=8 different wavelengths. Each of the demultiplexed optical signals of the five different wavelength groups is input to optical switches 230-1 to 230-Q (optical switches 230-1 to 230-5 in FIG. 2 ) via a transmission path.

[0013] Optical switches 230-1 to 230-5 are optical switches provided one for each of the optical signals of the five wavelength groups. Each of optical switches 230-1 to 230-5 has (P+R) (2+2=4 in FIG. 2 ) input ports, of which P=2 input ports are connected to output ports of wavelength group demultiplexers 210-1 to 210-2 that output optical signals of the corresponding wavelength groups. For example, the first output port of wavelength group demultiplexer 210-1 is connected to the input port of optical switch 230-1, and the fifth output port of wavelength group demultiplexer 210-1 is connected to 230-5. Similarly, the first output port of wavelength group demultiplexer 210-2 is connected to the input port of optical switch 230-1, and the fifth output port of wavelength group demultiplexer 210-2 is connected to 230-5. Then, in each of optical switches 230-1 to 230-5, the optical signals of the input wavelength groups are output from any output port. The connection relationships of the remaining R input ports of the optical switches 230-1 to 230-Q (that is, the input ports not connected to 210-1 to 210-Q) will be described separately later.

[0014] The wavelength group multiplexers 220-1 to 220-P (wavelength group multiplexers 220-1 to 220-2 in the figure) are connected to the output ports of the optical switches 230-1 to 230-5, and have the function of multiplexing the optical signals of the wavelength groups output from the optical switches 230-1 to 230-5 and outputting the multiplexed signals to the outside via a transmission path. Of the (P+R)= output ports of the optical switches 230-1 to 230-5, P=2 output ports are connected to the input ports of the wavelength group multiplexers 220-1 to 220-2 that input signals of the corresponding wavelength groups. For example, the first output port of the optical switch 230-1 is connected to the input port of the wavelength group multiplexer 220-1, and the second output port is connected to the input port of the wavelength group multiplexer 220-2. Similarly, the first output port of the optical switch 230-5 is connected to the input port of the wavelength group multiplexer 220-1, and the second output port is connected to the input port of the wavelength group multiplexer 220-2. The optical signals of the wavelength groups output from the two output ports of the optical switches 230-1 to 230-5 are multiplexed by the wavelength group multiplexers 220-1 and 220-2, respectively, and output to the outside.

[0015] Each of the optical switches 230-1 to 230-5 further includes R (2 in FIG. 2 ) output ports that are not connected to the wavelength group multiplexers 220-1 to 220-2. Now, assuming q=1, and focusing on the optical switch 230-1 that inputs and outputs optical signals of the first wavelength group, the R=2 output ports of the optical switch 230-1 are input to wavelength demultiplexers 240-q-1 to q-R (wavelength demultiplexers 240-1-1 to 1-2 in FIG. 2 ) with 1 input and S outputs (1 input, 8 outputs in FIG. 2 ). Each of the wavelength demultiplexers 240-1-1 to 1-2 has the function of outputting S=8 wavelengths that make up the q=1 wavelength group from a different port. Similarly, when q=2, the R=2 output ports of the optical switch 230-2 are input to wavelength demultiplexers 240-2-1 to 2-2 (not shown) with 1 input and 8 outputs, respectively.

[0016] Optical switches 260-1 to 260-40 are 2R input / 2R output (4 input / 4 output in FIG. 2 ) optical switches, each provided for a wavelength demultiplexed by wavelength demultiplexers 240-q-1 to q-R, with R=2 input ports connected to output ports of wavelength demultiplexers 240-q-1 to 240-q-R that output optical signals of the corresponding wavelengths. For example, the output ports of wavelength demultiplexers 240-1-1 to 240-1-2 are input to optical switches 260-1 to 260-8, as shown in FIG. 2 . Similarly, wavelength demultiplexers 240-2-1 to 2-2 (not shown) are connected to optical switches 260-9 to 260-16.

[0017] Each of the optical switches 230-1 to 230-5 further includes R (2 in FIG. 2) input ports that are not connected to the wavelength group demultiplexers 210-1 to 210-2. Now, assuming q=1, and focusing on the optical switch 230-1 that inputs and outputs optical signals of the first wavelength group, the R input ports of the optical switch 230-1 are connected to output ports of wavelength multiplexers 250-q-1 to 250-q-R (250-1-1 to 250-1-2 in FIG. 2), each with S inputs and 1 output (8 inputs and 1 output in FIG. 2). The wavelength multiplexers 250-1-1 to 250-1-2 have the function of multiplexing optical signals having different wavelengths and outputting optical signals of wavelength groups with S=8 outputs. The optical signals having different wavelengths are optical signals propagated from the R=8 output ports of the optical switches 260-1 to 260-8. That is, the output ports of optical switches 260-1 to 260-8 are connected to the input ports of wavelength multiplexers 250-1-1 to 250-1-2. Similarly, the output ports of optical switches 260-9 to 260-16 are connected to the input ports of wavelength multiplexers 250-2-1 to 250-2-2 (not shown).

[0018] Optical switches 260-1 to 260-40 further include R=2 output ports that are not connected to wavelength multiplexers 250-q-1 to 250-q-R. These output ports are connected to optical signal receiver groups. Optical switches 260-1 to 260-40 also include R=2 input ports that are not connected to wavelength demultiplexers 240-q-1 to 240-q-R. These input ports are connected to optical signal transmitter groups. Note that FIG. 2 depicts a configuration in which optical switch 260-1 is connected to a receiver group and a transmitter group by two optical fibers each (in other words, a configuration in which the receiver group is composed of two receivers and the transmitter group is composed of two transmitters), but this is intended as an example, and any number of receivers and transmitters can be installed depending on the design.

[0019] The optical transmission device 200 having such a configuration is configured so that, after an input optical signal (wavelength-multiplexed signal) input from a transmission path is demultiplexed into wavelength groups, it can be selected, depending on the routing settings of the optical switches 230-1 to 230-Q, whether the input optical signal is selected and input to wavelength group multiplexers 220-1 to 220-P and multiplexed before being output to the outside, or whether the input is selected and input to wavelength demultiplexers 240-q-1 to 240-q-R and demultiplexed into wavelength groups. Furthermore, the optical transmission device 200 is configured so that, depending on the routing settings of the optical switches 260-1 to 260-Q×S, it can be selected whether the optical signals demultiplexed by wavelength by wavelength demultiplexers 240-q-1 to 240-q-R are selected and received by a selected optical signal receiver, or whether the optical signals are selected and input to wavelength multiplexers 250-q-1 to 250-q-R and a wavelength group signal is generated.

[0020] Furthermore, the optical transmission device 200 is configured so that an optical signal output from a transmitter is selectively input to wavelength multiplexers 250-q-1 to 250-q-R by route setting of optical switches 260-1 to 260-Q×S, and a wavelength-group signal is generated. Similarly, the optical transmission device 200 is also configured so that a wavelength-group signal generated by wavelength multiplexers 250-q-1 to 250-q-R is selectively input to wavelength-group multiplexers 220-1 to 220-P by route setting of optical switches 230-1 to 230-Q, and is multiplexed and then output to the outside.

[0021] By using such an optical transmission device 200, a user can select whether to route an input optical signal (wavelength multiplexed signal) in units of wavelength or in units of wavelength group. Compared to devices that perform route control entirely in units of wavelength, this optical transmission device 200 can reduce the degree of freedom in route control by providing a processing hierarchy for wavelength groups, which has a coarse routing control granularity, and can also simplify the device configuration.

[0022] Typically, the amount of data that can be transmitted through a single optical fiber is limited to the product of the number of signals that can be wavelength-multiplexed on the optical fiber and the signal speed of the optical transmitter / receiver. However, recent technological trends in optical transmission devices have made it difficult to improve frequency utilization efficiency. Therefore, to double the signal speed, the occupied wavelength band also doubles, and the number of signals that can be wavelength-multiplexed is halved, resulting in no increase in the amount of data that can be transmitted through a single optical fiber. Under these circumstances, one way to increase the amount of data that can be transmitted through a single optical fiber is to widen the wavelength band used for transmission.

[0023] Generally, the wavelength band used for transmission is determined by optical devices that have limitations on the wavelengths that can be used, and in many cases, the wavelength range that can be amplified by an optical amplifier coincides with the wavelength band used for transmission. In this case, widening the wavelength band used for transmission means using multiple types of optical amplifiers that can be used in different wavelength ranges for optical transmission.

[0024] However, the conventional optical transmission device 100 is not designed to accommodate multiple types of optical amplifiers with different amplifiable wavelength ranges, and is therefore not easily adaptable to multiple types of optical amplifiers. In contrast, the optical transmission device 200 includes wavelength group demultiplexers 210-1 to 210-P and wavelength group multiplexers 220-1 to 220-P, and is therefore easily adaptable to multiple types of optical amplifiers by matching the amplifiable wavelength ranges with the wavelength groups.

[0025] However, in recent optical transmission equipment, the number of signals that can be wavelength-division multiplexed onto a single optical fiber has tended to decrease, and the bandwidth of signals that follow the same route has been increasing year by year (the rule of thumb is that it has increased tenfold in about ten years). Given these trends, it is possible that in future optical transmission equipment, the ability to control individual optical fiber cores may become more important than the ability to control signals so that each wavelength follows a different route.

[0026] T. Watanabe, K. Suzuki and T. Takahashi: “Silica-based PLC transponder aggregators for colorless, directionless, and contentionless ROADM,” Optical Fiber Communication Conference (OFC), Paper OTh3D.1 (2012). O. Moriwaki et al., “Terabit-scale hierarchical compact optical cross-connect system employing PLC devices and optical backplane,” 2010 Conference on Optical Fiber Communication (OFC / NFOEC), collocated National Fiber Optic Engineers Conference, Paper PDPC9 (2010).

[0027] The present disclosure has been made in consideration of the above-mentioned problems, and its purpose is to provide an optical transmission device that is both easily configured to apply multiple types of optical amplifiers with different amplifiable wavelength ranges and capable of performing route control on an optical fiber core-by-core basis.

[0028] In order to achieve such an object, the present disclosure provides an optical transmission device having one or more input / output ports for wavelength-multiplexed signals, the optical transmission device including: a first wavelength group demultiplexer that demultiplexes an input wavelength-multiplexed signal into optical signals of two or more wavelength groups; a plurality of optical amplifiers that amplify each of the optical signals of the wavelength groups output from the wavelength group demultiplexer; an optical signal receiving function unit that receives a desired optical signal from the optical signals of the wavelength group amplified by the optical amplifier; and an optical signal transmitting function unit that generates the desired optical signal; and an optical signal transmitting function unit that is disposed on the output side of each of the optical amplifiers and that determines whether the amplified optical signal of the wavelength group is propagated to the optical signal receiving function unit or passes through as is in response to a control signal from a user. and an optical switch function unit configured to select and output either an optical signal of a passed wavelength group or a desired optical signal generated by the optical signal transmission function unit in response to a control signal from a user; a first wavelength group multiplexer arranged on the output side of the optical switch function unit, which multiplexes and outputs, for each input / output port, each of the optical signals of the wavelength group amplified by the optical amplifier and each of the desired optical signals generated by the optical signal transmission function unit; and a multi-input multi-output first optical switch configured to allow a user to select an output route for the optical signal output from each of the wavelength group multiplexers for each input port.

[0029] 1 is a diagram showing a conceptual configuration of an optical transmission device 100 having the form of a CDC-ROADM according to the prior art; FIG. 2 is a diagram showing a conceptual configuration of an optical transmission device 200 according to the prior art; FIG. 3 is a diagram showing a conceptual configuration of an optical transmission device 300 according to the present disclosure; FIG. 4 is a diagram showing another conceptual configuration of the optical transmission device 300 according to the present disclosure; FIG. 5 is a conceptual diagram showing exemplary configurations of an optical signal receiving function unit 311 and an optical signal transmitting function unit 312 constituting the optical transmission device 300 according to the present disclosure, where (a) shows the configuration of the optical signal receiving function unit 311 and (b) shows the configuration of the optical signal transmitting function unit 312; FIG. 6 is a conceptual diagram showing another exemplary configuration of the optical signal receiving function unit 311 and the optical signal transmitting function unit 312 constituting the optical transmission device 300 according to the present disclosure, where (a) shows the configuration of the optical signal receiving function unit 311 and (b) shows the configuration of the optical signal transmitting function unit 312. 1A and 1B are conceptual diagrams showing another exemplary configuration of the optical signal receiving function unit 311 and the optical signal transmitting function unit 312 constituting the optical transmission device 300 according to the present disclosure, where (a) shows the configuration of the optical signal receiving function unit 311 and (b) shows the configuration of the optical signal transmitting function unit 312. 1A and 1B are conceptual diagrams showing another exemplary configuration of the optical signal receiving function unit 311 and the optical signal transmitting function unit 312 constituting the optical transmission device 300 according to the present disclosure, where (a) shows the configuration of the optical signal receiving function unit 311 and (b) shows the configuration of the optical signal transmitting function unit 312. 1B are conceptual diagrams showing another exemplary configuration of the optical signal receiving function unit 311 and the optical signal transmitting function unit 312 constituting the optical transmission device 300 according to the present disclosure, where (a) shows the configuration of the optical signal receiving function unit 311 and (b) shows the configuration of the optical signal transmitting function unit 312.

[0030] Various embodiments of the present disclosure will be described in detail below with reference to the drawings. The same or similar reference numerals indicate the same or similar elements, and redundant description may be omitted. Materials and numerical values ​​are for illustrative purposes only and are not intended to limit the technical scope of the present disclosure. The following description is an example, and some configurations may be omitted or modified, or additional configurations may be added, as long as they do not deviate from the gist of one embodiment of the present disclosure.

[0031] FIG. 3 is a diagram conceptually illustrating the configuration of an optical transmission device 300 according to the present disclosure. As shown in FIG. 3, the optical transmission device 300 is an optical transmission device having one or more input ports for inputting and outputting wavelength-multiplexed signals, and one or more output ports. The optical transmission device 300 includes wavelength group demultiplexers 303a and 303b connected to each of the input ports of the optical transmission device 300 and demultiplexing the wavelength-multiplexed signal input to each input port into optical signals of two or more wavelength groups, optical amplifiers 304a1 to 304a3 and 304b1 to 304b3 connected to each output port of the wavelength group demultiplexers 303a and 303b and configured to be able to amplify the wavelength range of the optical signals of each demultiplexed wavelength group, single-input multiple-output optical switches 305a1 to 305a3 and 305b1 to 305b3 connected to each output port of the optical amplifiers 304a1 to 304a3 and 304b1 to 304b3, and one of the output ports of the optical switches 305a1 to 305a3 and 305b1 to 305b3. The optical signal receiving function unit 311 is connected to the output ports of the connected multiple-input, single-output optical switches 306a1-306a3, 306b1-306b3, and the optical signal receiving function unit 311 is connected to the output ports of the optical switches 305a1-305a3, 305b1-305b3 that are not connected to the optical switches 306a1-306a3, 306b1-306b3. Among the ports, the optical signal transmission function unit 312 is connected to an input port that is not connected to an output port of the optical switches 305a1-305a3, 305b1-305b3, wavelength group multiplexers 307a, b are connected to the output ports of each of the optical switches 306a1-306a3, 306b1-306b3, and a multi-input multi-output optical switch 308 is connected to the output ports of each of the wavelength group multiplexers 307a, b.

[0032] Although FIG. 3 illustrates two pairs of input and output ports of the optical transmission device 300, this is for illustrative purposes only, and the number of input and output ports of the optical transmission device 300 may be any number depending on the design.

[0033] Furthermore, in FIG. 3, three optical amplifiers 304, three optical switches 305, and three optical switches 306 are arranged for each pair of input and output ports, but this is intended as an example, and any number of optical amplifiers 304, optical switches 305, and optical switches 306 may be arranged depending on the design.

[0034] When a wavelength-multiplexed signal is input from outside the optical transmission device 300, the externally input wavelength-multiplexed signal is demultiplexed into optical signals of two or more wavelength groups (three in FIG. 3 ) by each of the wavelength group demultiplexers 303 a and 303 b. Each of the demultiplexed optical signals of the wavelength groups is input to the optical amplifiers 304 a 1 to 304 a 3 and 304 b 1 to 304 b 3. Examples of combinations of wavelength groups and optical amplifier 304 settings include when the wavelength group is the C band and the optical amplifier 304 is a C-band EDFA, when the wavelength group is the L band and the optical amplifier 304 is an L-band EDFA, or when the wavelength group is the S band and the optical amplifier 304 is a thulium-doped fiber amplifier TDFA.

[0035] Optical switches 305a1-305a3, 305b1-305b3 are configured in advance to determine, in response to a control signal from a user, whether to output the optical signals of the wavelength group amplified by optical amplifiers 304a1-304a3, 304b1-304b3 to optical switches 306a1-306a3, 306b1-306b3 or optical signal receiving function unit 311. Meanwhile, optical switches 306a1-306a3, 306b1-306b3 are configured to output either the optical signals of the wavelength group propagated from optical switches 305a1-305a3, 305b1-305b3 or light input from optical signal transmitting function unit 312, in response to a control signal from a user.

[0036] The optical signal receiving functional unit 311 and the optical signal transmitting functional unit 312 are configured to input and output desired optical signals to and from their own nodes, and perform the add / drop function in the ROADM system. That is, if a user selects (controls) any of the optical switches 305 to propagate an amplified optical signal of the wavelength group to the optical signal receiving functional unit 311, the signal is output (dropped) to the own node, and if the amplified optical signal of the wavelength group and the optical signal transmitted from the optical signal transmitting functional unit 312 are combined in any of the optical switches 306, the signal is input (added) to the own node. Note that, depending on the settings (user control) of the optical switches 305 and 306, the amplified optical signal of the wavelength group can also be passed through (though) as is.

[0037] In FIG. 3, the optical switches 305 and 306 are depicted as separate, independent optical switches, but these may be replaced with an integrated multi-input, multi-output optical switch.

[0038] The number of input ports of the optical signal receiving functional unit 311 and the number of output ports of the optical signal transmitting functional unit 312 are each the product of the input ports of the optical transmission device 300 and the type of optical amplifier 304 (corresponding to the number of wavelength groups used by the optical transmission device 300). Detailed configurations of each of the optical signal receiving functional unit 311 and the optical signal transmitting functional unit 312 will be described later with reference to FIGS. 5 to 9.

[0039] Wavelength group multiplexer 307a multiplexes (combines) the optical signals of the wavelength groups output from each of optical switches 306a1-306a3, and outputs the multiplexed signals to optical switch 308. Similarly, wavelength group multiplexer 307b multiplexes the optical signals of the wavelength groups output from each of optical switches 306b1-306b3, and outputs the multiplexed signals to optical switch 308. Optical switch 308 is configured in advance to determine the output route of the wavelength multiplexed signals input from wavelength group multiplexers 307a and 307b in response to a control signal from the user.

[0040] The optical transmission device 300 according to the present disclosure may further include first optical multiplexers 301 a, b on the input sides of the wavelength group demultiplexers 303 a, b, and optical signal sources 302 a, b that input optical signals to the first optical multiplexers 301 a, b, as shown in Fig. 4. In addition, the optical transmission device 300 according to the present disclosure may include second optical multiplexers 309 a, b on the output side of the optical switch 308, and second optical signal sources 310 a, b that input optical signals to the second optical multiplexers 309 a, b, as shown in Fig. 4.

[0041] The first optical multiplexing means 301a, b has a common port that serves as the input side for an externally input wavelength-multiplexed signal and the output side for an optical signal with a shorter wavelength than the externally input wavelength-multiplexed signal, a long-wavelength port connected to the wavelength group demultiplexer 303, and a short-wavelength port connected to a light source (first optical signal source 302a, b described below) for an optical signal with a shorter wavelength than the wavelength-multiplexed signal. The first optical multiplexing means 301a, b having such a configuration corresponds to a device generally called a WDM coupler, and has the function of inputting an externally input wavelength-multiplexed signal from the common port, outputting it from the long-wavelength port, and propagating it to the wavelength group demultiplexer. Furthermore, the first optical multiplexing means 301a, b also has the function of propagating an optical signal with a shorter wavelength than the externally input wavelength-multiplexed signal from the short-wavelength port to the common port, i.e., in the opposite direction to the other optical signal (the externally input wavelength-multiplexed signal). This function makes it possible to amplify the optical signal intensity of some or all of the other signal light. Optical signals having wavelengths shorter than the wavelength multiplexed signal input from outside are output from first optical signal sources 302a and 302b. The first optical signal source 302 may be a Raman pump light source that amplifies a certain wavelength range on the super wavelength side of the light source by propagating a high signal level through a transmission line. Note that the optical transmission device 300 may be configured such that the same function as the first optical multiplexing means 301a and 301b is realized inside the wavelength group demultiplexer 303.

[0042] The second optical multiplexing means 309a, b has a common port that serves as the output side for the wavelength-multiplexed signal input to the optical switch 308 and for optical signals with wavelengths shorter than the wavelength-multiplexed signal input from an external source, a long-wavelength port connected to the optical switch 308, and a short-wavelength port connected to a light source (second optical signal source 310a, b described below) for optical signals with wavelengths shorter than the wavelength-multiplexed signal. The second optical multiplexing means 309a, b having this configuration corresponds to a device generally called a WDM coupler, and has the function of inputting the wavelength-multiplexed signal output from the optical switch 308 through the long-wavelength port and propagating it to the outside. Furthermore, the second optical multiplexing means 309a, b also has the function of propagating light with wavelengths shorter than the wavelength-multiplexed signal input from an external source from the short-wavelength port to the common port, i.e., propagating light with wavelengths shorter than the wavelength-multiplexed signal input from an external source, in the same direction as other signal light (optical signal output from the optical switch 308). This function makes it possible to amplify the optical signal intensity of some or all of the other signal light. Optical signals having wavelengths shorter than the wavelength-multiplexed signal output from the optical switch 308 are output from second optical signal sources 310a, b. The second optical signal sources 310a, b may be Raman pump light sources that amplify a certain wavelength range on the super wavelength side of the light source by propagating a high signal level through a transmission line. Note that the optical transmission device 300 may be configured such that the same function as the second optical multiplexing means 309a, b is realized within the optical switch 308.

[0043] 5A and 5B are conceptual diagrams showing exemplary configurations of the optical signal receiving function unit 311 and the optical signal transmitting function unit 312 constituting the optical transmission device 300 according to the present disclosure, where (a) shows the configuration of the optical signal receiving function unit 311 and (b) shows the configuration of the optical signal transmitting function unit 312. In one example, the optical signal receiving function unit 311 constituting the optical transmission device 300 according to the present disclosure includes, as shown in FIG. 4A, demultiplexers 400a-c connected to the respective output ports of the optical switch 305, and optical receivers 401a1, a2, 401b1, b2, 401c1, and c2 connected to the respective output ports of the demultiplexers 400a-c. On the other hand, the optical signal transmitting function unit 312 includes multiplexers 402a-c connected to the respective input ports of the optical switch 306, and optical transmitters 403a1, a2, 403b1, b2, 403c1, c2 connected to the respective input ports of the multiplexers 402a-c, as shown in FIG. 4(b).

[0044] In this example, the wavelengths that each of the demultiplexers 400a-c can demultiplex are predetermined according to the output port. Similarly, the wavelengths that each of the multiplexers 402a-c can multiplex are predetermined according to the input port. That is, the wavelengths of the optical signals received by each of the optical receivers 401a1, a2, 401b1, b2, 401c1, and c2 are determined by the demultiplexers 400a-c. Similarly, the wavelengths of the optical signals transmitted by each of the optical transmitters 403a1, a2, 403b1, b2, 403c1, and c2 are determined by the multiplexers 402a-c.

[0045] In the optical transmission device 300 according to the present disclosure having such a configuration, assume that the optical signal receiving unit 311 receives an optical signal of a wavelength group that has passed through one of the optical amplifiers 304 corresponding to the same wavelength group, and the optical signal output from the optical signal transmitting unit 312 is combined with the path of the optical signal of the wavelength group that has passed through the other optical amplifier corresponding to the same wavelength group. In such a case, as described above, the signal wavelength and input route received by the optical receiver 401 and the signal wavelength and output route sent by the optical transmitter 403 are determined by the demultiplexer 400 and the multiplexer 402, and therefore the device does not have the functions known as colorless (the ability to output any wavelength) or directionless (the ability to output to any route). However, the provision of multiple optical amplifiers 304 makes it easy to apply multiple types of optical amplifiers with different amplifiable wavelength ranges, and enables signal control for each core of the optical fiber for the wavelength-multiplexed signals input from each optical fiber to the input ports of the optical transmission device 300 connected to each of the wavelength group demultiplexers 303 a and 303 b.

[0046] 6A and 6B are conceptual diagrams showing another exemplary configuration of the optical signal receiving functional unit 311 and the optical signal transmitting functional unit 312 constituting the optical transmission device 300 according to the present disclosure, where (a) shows the configuration of the optical signal receiving functional unit 311 and (b) shows the configuration of the optical signal transmitting functional unit 312. In one example, the optical signal receiving functional unit 311 constituting the optical transmission device 300 according to the present disclosure includes, as shown in FIG. 6A, demultiplexers 404a-c connected to output ports of the optical amplifier 304, and optical receivers 401a1, a2, 401b1, b2, 401c1, and c2 connected to the output ports of the demultiplexers 404a-c, respectively. On the other hand, the optical signal transmitting function unit 312 includes multiplexers 405a-c connected to the respective input ports of the optical switch 306, and optical transmitters 403a1, a2, 403b1, b2, 403c1, c2 connected to the respective input ports of the multiplexers 405a-c, as shown in FIG. 5(b).

[0047] In the optical signal receiving function unit 311 illustrated in FIG. 6(a), unlike the configuration illustrated in FIG. 5(a), the demultiplexers 404a-c are configured so that the wavelengths output to the output ports can be set arbitrarily. For example, the demultiplexers 404a-c can be WSSs. Similarly, in the optical signal transmitting function unit 312 illustrated in FIG. 6(b), unlike the configuration illustrated in FIG. 5(b), the multiplexers 405a-c are configured so that the wavelengths input to the input ports can be set arbitrarily. For example, the multiplexers 405a-c can be WSSs.

[0048] The demultiplexers 404a-c may be configured to be capable of demultiplexing input optical signals without wavelength dependency, and the multiplexers 405a-c may be configured to be capable of multiplexing input optical signals without wavelength dependency. For example, the demultiplexers 404a-c may be optical splitters, and the multiplexers 405a-c may be optical couplers.

[0049] Even in the optical transmission device 300 according to the present disclosure having such a configuration, when the optical signal receiving function unit 311 receives an optical signal of a wavelength group that has passed through one of the optical amplifiers 304 corresponding to the same wavelength group, and the optical signal output from the optical signal transmitting function unit 312 is merged into the path of the optical signal of the wavelength group that has passed through one of the optical amplifiers corresponding to the same wavelength group, as described above, the signal wavelength received by the optical receiver 401 can be changed by setting the demultiplexer 400, and the input direction is determined by the demultiplexer 400, and the signal wavelength sent by the optical transmitter 403 can be changed by setting the multiplexer 405, and the input direction is determined by the multiplexer 405, so a function called colorless (capable of outputting any wavelength) is realized, but the function called directionless (capable of outputting to any direction) is not provided. However, by arranging multiple optical amplifiers 304, it is easy to apply multiple types of optical amplifiers with different amplifiable wavelength ranges, and it becomes possible to control the wavelength-multiplexed signals input from each optical fiber to the input ports of the optical transmission device 300 connected to each of the wavelength group demultiplexers 303a, b on a core-wire basis for each optical fiber.

[0050] 7A and 7B are conceptual diagrams showing another exemplary configuration of the optical signal receiving function unit 311 and the optical signal transmitting function unit 312 constituting the optical transmission device 300 according to the present disclosure, where (a) shows the configuration of the optical signal receiving function unit 311 and (b) shows the configuration of the optical signal transmitting function unit 312. In one example, the optical signal receiving function unit 311 constituting the optical transmission device 300 according to the present disclosure includes, as shown in FIG. 7( a), demultiplexers 406a-c connected to the output ports of the optical amplifier 304, single-input, multiple-output optical switches 407a1, b1, c1, 407a2, b2, c2 connected to the multiple output ports of the demultiplexers 406a-c, multiple-input, single-output optical switches 408a1, b1, c1 connected to the output ports of the optical switches 407a1, b1, c1, multiple-input, single-output optical switches 408a2, b2, c2 connected to the output ports of the optical switches 407a2, b2, c2, and optical receivers 401a1, a2, 401b1, b2, 401c1, c2 connected to the output ports of the optical switches 408a1, b1, c1, 408a2, b2, c2, Similarly, as shown in FIG. 7(b), the optical signal transmission function unit 312 includes a multiplexer 409 connected to each input port of the optical switch 306, multiple-input, single-output optical switches 410a1, b1, c1, 410a2, b2, c2 connected to each of the multiple input ports of the multiplexers 409a-c, single-input, multiple-output optical switches 411a1, b1, c1 connected to each input port of the optical switches 410a1, b1, c1, single-input, multiple-output optical switches 411a2, b2, c2 connected to each input port of the optical switches 410a2, b2, c2, and optical transmitters 403a1, a2, 402b1, b2, 403c1, c2 connected to each input port of the optical switches 411a1, b1, c1, 411a2, b2, c2.

[0051] In this example, the provision of optical switches 407 and 408 enables the user to control to which optical receiver 401 an optical signal of the wavelength group input to the optical signal receiving function unit 311 is to be guided. Similarly, in the above example, the provision of optical switches 410 and 411 enables the user to control from which optical transmitter 403 of the optical signal transmitting function unit 312 an optical signal of the wavelength group input is to be output.

[0052] In the optical transmission device 300 according to the present disclosure having such a configuration, it is assumed that the optical signal receiving functional unit 311 receives an optical signal of a wavelength group that has passed through one of the optical amplifiers 304 corresponding to the same wavelength group, and the optical signal output from the optical signal transmitting functional unit 312 is combined with the path of the optical signal of the wavelength group that has passed through the optical amplifier corresponding to the same wavelength group. In such a case, the wavelengths of the optical signals received by each optical receiver 401 and the optical signals transmitted by each optical transmitter 403 are determined by the ports used by the demultiplexer 406 and the multiplexer 409. Meanwhile, the input path of the signal received by the optical receiver 401 and the output path of the signal transmitted by the optical transmitter 403 can be arbitrarily set by the user through control of the optical switches 407, 408 and the optical switches 410, 411, and are not affected by the path settings of the other optical receivers 401 and optical transmitters 403. Therefore, the optical transmission device 300 does not have a function called colorless (capable of outputting any wavelength), but it does have functions called directionless (capable of outputting to any route) and contentionless (no wavelength or route collisions). Furthermore, the provision of multiple optical amplifiers 304 makes it easy to apply multiple types of optical amplifiers with different amplifiable wavelength ranges, and enables signal control for each core of the optical fiber for wavelength-multiplexed signals input from each optical fiber to the input ports of the optical transmission device 300 connected to each of the wavelength group demultiplexers 303 a, b.

[0053] 8A and 8B are conceptual diagrams showing another exemplary configuration of the optical signal receiving functional unit 311 and the optical signal transmitting functional unit 312 constituting the optical transmission device 300 according to the present disclosure, where (a) shows the configuration of the optical signal receiving functional unit 311 and (b) shows the configuration of the optical signal transmitting functional unit 312. In one example, the optical signal receiving functional unit 311 constituting the optical transmission device 300 according to the present disclosure includes, as shown in FIG. 8A, demultiplexers 412a-c connected to the output port of the optical amplifier 304, multiple-input, single-output optical switches 413a-f connected to each of the multiple output ports of the demultiplexers 412a-c, and optical receivers 401a-f connected to each of the output ports of the optical switches 413a-f. Similarly, as shown in FIG. 8(b), the optical signal transmission function unit 312 includes multiplexers 414a-c connected to each input port of the optical switch 306, single-input, multiple-output optical switches 415a-f connected to each of the multiple input ports of the multiplexers 414a-c, and optical transmitters 403a-f connected to each input port of the optical switches 415a-f.

[0054] In such an example, the demultiplexers 412a-c are configured so that the output wavelength can be set or the demultiplexing can be performed wavelength-independently, and the multiplexers 414a-c are also configured so that the input wavelength can be set or the multiplexing can be performed wavelength-independently.

[0055] Furthermore, the optical switches 413a-f and the optical switches 415a-f each allow the user to arbitrarily control the output path of an optical signal.

[0056] In the optical transmission device 300 according to the present disclosure having such a configuration, it is assumed that the optical signal receiving unit 311 receives an optical signal of a wavelength group that has passed through one of the optical amplifiers 304 corresponding to the same wavelength group, and the optical signal output from the optical signal transmitting unit 312 is merged with the path of the optical signal of the wavelength group that has passed through the optical amplifier corresponding to the same wavelength group. In such a case, the wavelengths of the optical signals received by each optical receiver 401 and the optical signals transmitted by each optical transmitter 403 can be arbitrarily set in response to a control signal from a user. Similarly, the input path of the signal received by the optical receiver 401 and the output path of the signal transmitted by the optical transmitter 403 can also be arbitrarily set by the user, and are not affected by the path settings of other optical receivers 401 and optical transmitters 403. Therefore, the optical transmission device 300 achieves functions called colorless (capable of outputting any wavelength), directionless (capable of outputting to any path), and contentionless (no collisions between wavelengths and paths). Furthermore, by arranging multiple optical amplifiers 304, it is easy to apply multiple types of optical amplifiers with different amplifiable wavelength ranges, and it becomes possible to control the wavelength-multiplexed signals input from each optical fiber to the input ports of the optical transmission device 300 connected to each of the wavelength group demultiplexers 303a, b on a core-wire basis for that optical fiber.

[0057] 9A and 9B are conceptual diagrams showing another exemplary configuration of the optical signal receiving functional unit 311 and the optical signal transmitting functional unit 312 constituting the optical transmission device 300 according to the present disclosure, where (a) shows the configuration of the optical signal receiving functional unit 311 and (b) shows the configuration of the optical signal transmitting functional unit 312. In one example, the optical signal receiving functional unit 311 constituting the optical transmission device 300 according to the present disclosure includes, as shown in FIG. 9A, wavelength group multiplexers 416a-c connected to output ports of the optical switch 305, demultiplexers 417a-c connected to output ports of the wavelength group multiplexers 416a-c, multiple-input, single-output optical switches 418a-f connected to each output port of the demultiplexers 417a-c, and optical receivers 401a-f connected to each output port of the optical switches 418a-f. Similarly, as shown in FIG. 9(b), the optical signal transmission function unit 312 includes wavelength group demultiplexers 419a-c connected to the input ports of the optical switch 306, multiplexers 420a-c connected to the input ports of the wavelength group demultiplexers 419a-c, single-input, multiple-output optical switches 421a-f connected to each input port of the multiplexers 420a-c, and optical transmitters 403a-f connected to each input port of the optical switches 421a-f.

[0058] In such an example, the demultiplexers 417a-c are configured so that the output wavelength can be set or the demultiplexing can be performed wavelength-independently, and the multiplexers 420a-c are also configured so that the input wavelength can be set or the multiplexing can be performed wavelength-independently.

[0059] In the optical transmission device 300 according to the present disclosure having such a configuration, it is assumed that the optical signal receiving unit 311 receives optical signals of multiple wavelength groups via the optical amplifier 304, and the optical signal output from the optical signal transmitting unit 312 is merged with the path of the optical signal of the wavelength group that has passed through the optical amplifier 304. In such a case, the wavelengths of the optical signals received by each optical receiver 401 and the optical signals transmitted by each optical transmitter 403 can be arbitrarily set in response to a control signal from a user. Similarly, the input path of the signal received by the optical receiver 401 and the output path of the signal transmitted by the optical transmitter 403 can also be arbitrarily set by the user, and are not affected by the path settings of other optical receivers 401 and optical transmitters 403. Therefore, except for the ability to set paths across multiple wavelength groups, the optical transmission device 300, like the embodiment shown in FIG. 8, achieves functions known as colorless (capable of outputting any wavelength), directionless (capable of outputting to any path), and contentionless (no collisions between wavelengths and paths). Furthermore, by arranging multiple optical amplifiers 304, it is easy to apply multiple types of optical amplifiers with different amplifiable wavelength ranges, and it becomes possible to control the wavelength-multiplexed signals input from each optical fiber to the input ports of the optical transmission device 300 connected to each of the wavelength group demultiplexers 303a, b on a core-wire basis for that optical fiber.

[0060] In yet another example, the optical signal receiving function unit 311 to which signal light of a wavelength group that has passed through an optical amplifier corresponding to one or more wavelength groups is input and the optical signal transmitting function unit 312 that merges into the path can also be configured in the same way as the optical transmission device 100.

[0061] As described above, the optical transmission device according to the present disclosure has a configuration that can easily apply multiple types of optical amplifiers with different amplifiable wavelength ranges and can perform path control for each optical fiber core. Such an optical transmission device is expected to be put into practical use as an optical transmission device that can transmit a much larger amount of data than conventional technology.

[0062] 100 Optical transmission device 110 Wavelength selective switch (WSS) 130 Receiver transponder aggregator (TPA) 131 Output optical splitter 132 Optical switch 141 Optical switch 142 Optical coupler 200 Optical transmission device 210-1 Wavelength group demultiplexer 210-2 Wavelength group demultiplexer 220-1 Wavelength group multiplexer 220-2 Wavelength group multiplexer 230-1 Optical switch 230-2 Optical switch 230-5 Optical switch 240-q-R Wavelength demultiplexer 250-q-R Wavelength multiplexer 260-1 Optical switch 260-40 Optical switch 260-9 Optical switch 260-Q Optical switch 300 Optical transmission device 301, 301a, b First optical multiplexing means 302, 302a, b First optical signal source 303, 303a, b Wavelength group demultiplexer 304, 304a1-304a3, 304b1-304b3 Optical amplifier 305, 305a1-305a3, 305b1-305b3 Optical switch 306, 306a1-306a3, 306b1-306b3 Optical switch 307a, b Wavelength group multiplexer 308 Optical switch 309a, b Second optical multiplexing means 310a, b Second optical signal source 311 Optical signal receiving function unit 312 Optical signal transmitting function unit 400, 400a-c Demultiplexer 401, 401a1, a2, 401b1, b2, 401c1, c2, 401a-f Optical receiver 402, 402a-c Multiplexer 403, 403a1, a2, 403b1, b2, 403c1, c2, 403a-f Optical transmitter 404a-c Demultiplexer 405a-c Multiplexer 406, 406a-c Demultiplexer 407, 407a1, b1, c1, 407a2, b2, c2 Optical switch 408, 408a1, b1, c1, 408a2, b2, c2 Optical switch 409, 409a-c Multiplexer 410, 410a1, b1, c1, 410a2, b2, c2 Optical switch 411, 411a1, b1, c1, 411a2, b2, c2 Optical switch 412, 412a-c Demultiplexers 413, 413a-f Optical switches 414, 414a-c Multiplexers 415, 415a-f Optical switches 416, 416a-c Wavelength group multiplexers 417, 417a-c Demultiplexers 418, 418a-f Optical switches 419, 419a-c Wavelength group demultiplexers 420, 420a-c Multiplexers 421, 421a-f Optical switches

Claims

1. An optical transmission device having one or a plurality of input / output ports for wavelength multiplexed signals, comprising: a first wavelength group demultiplexer that demultiplexes the input wavelength multiplexed signal into optical signals of two or more wavelength groups; a plurality of optical amplifiers that amplify each of the optical signals of the wavelength group output from the wavelength group demultiplexer; an optical signal receiving function unit that receives a desired optical signal from the optical signals of the wavelength group amplified by the optical amplifiers; an optical signal transmitting function unit that generates the desired optical signal; an optical switch function unit that is disposed on the output side of each of the optical amplifiers and configured to determine whether the amplified optical signal of the wavelength group is propagated to the optical signal receiving function unit or passed through as is in response to a control signal from a user, and to determine, in response to a control signal from the user, whether to select and output either the optical signal of the wavelength group that has been passed through or the desired optical signal generated by the optical signal transmitting function unit; and a first wavelength group multiplexer that is disposed on the output side of the optical switch function unit and multiplexes and outputs, for each of the input / output ports, each of the optical signals of the wavelength group amplified by the optical amplifiers and each of the desired optical signals generated by the optical signal transmitting function unit. a first optical switch with multiple inputs and multiple outputs configured to allow the user to select an output route of an optical signal output from each of the wavelength group multiplexers for each port on the input side of the input / output ports.

2. The optical transmission device of claim 1, wherein the optical signal receiving function unit further comprises: a plurality of input ports connected to output ports of the optical switch function unit; a plurality of demultiplexers that demultiplex optical signals of the wavelength group input from the input ports and amplified by each of the optical amplifiers; and a plurality of receivers that receive the optical signals demultiplexed by each of the demultiplexers; and the optical signal transmitting function unit further comprises: a plurality of transmitters that generate optical signals; a plurality of multiplexers that multiplex the optical signals input from the transmitters to generate the desired signal; and output ports arranged on the output side of the multiplexers and on the input side of the optical switch function unit; and each of the demultiplexers has predetermined wavelengths that it can demultiplex according to the output port, and each of the multiplexers has predetermined wavelengths that it can multiplex according to the input port.

3. The optical transmission device of claim 1, wherein the optical signal receiving function unit further comprises: a plurality of input ports connected to output ports of the optical switch function unit; a plurality of demultiplexers that demultiplex the optical signals of the wavelength group input from the input ports and amplified by each of the optical amplifiers; and a plurality of receivers that receive the optical signals demultiplexed by each of the demultiplexers; and the optical signal transmitting function unit further comprises: a plurality of transmitters that generate optical signals; a plurality of multiplexers that multiplex the optical signals input from the transmitters to generate the desired signal; and output ports arranged on the output side of the multiplexers and on the input side of the optical switch function unit; each of the demultiplexers is configured to be able to arbitrarily set the wavelength to be output to the output port; and each of the multiplexers is configured to be able to arbitrarily set the wavelength to be input to the input port.

4. The optical transmission device of claim 1, wherein the optical signal receiving function unit further comprises: a plurality of input ports connected to output ports of the optical switch function unit; a plurality of demultiplexers that demultiplex optical signals of the wavelength group input from the input ports and amplified by each of the optical amplifiers; a plurality of receivers that receive the optical signals demultiplexed by each of the demultiplexers; and a second optical switch installed on the output side of each of the receivers; and the optical signal transmitting function unit further comprises: a plurality of transmitters that generate optical signals; a plurality of multiplexers that multiplex the optical signals input from the transmitters to generate the desired signal; output ports located on the output sides of the multiplexers and on the input side of the optical switch function unit; and a third optical switch installed on the output side of each of the transmitters.

5. The optical transmission device according to claim 4, wherein each of the demultiplexers is configured so that the wavelength to be output to the output port can be set arbitrarily, and each of the multiplexers is configured so that the wavelength to be input to the input port can be set arbitrarily.

6. The optical transmission device according to claim 4, wherein each of said demultiplexers is an optical splitter, and each of said multiplexers is an optical coupler.

7. An optical transmission device as claimed in any one of claims 4 to 6, wherein the optical signal receiving function unit further comprises a second wavelength group multiplexer on the input side of each of the demultiplexers, and the optical signal transmitting function unit further comprises a second wavelength group demultiplexer on the output side of each of the demultiplexers.

8. The optical transmission device according to claim 1, further comprising a first optical signal source that generates an optical signal having a shorter wavelength than the wavelength multiplexed signal and inputs the shorter wavelength optical signal to the first wavelength group demultiplexer, the first wavelength group demultiplexer being configured to multiplex the shorter wavelength optical signal and the input wavelength multiplexed signal and to propagate the shorter wavelength optical signal in a direction opposite to that of the input wavelength multiplexed signal.

9. The optical transmission device according to claim 1, further comprising: a first optical signal source that generates an optical signal having a shorter wavelength than the wavelength multiplexed signal; and first optical multiplexing means that is further configured to multiplex the optical signal having the shorter wavelength and the wavelength multiplexed signal input from outside, and to propagate the optical signal having the shorter wavelength in a direction opposite to that of the wavelength multiplexed signal input from outside.

10. The optical transmission device according to claim 1, further comprising a second optical signal source that generates an optical signal having a shorter wavelength than the optical signal output from the first optical switch and inputs the shorter wavelength optical signal to the first optical switch, and the first optical switch is configured to multiplex the shorter wavelength optical signal and the wavelength multiplexed signal output from the wavelength group multiplexer and propagate the shorter wavelength optical signal in the same direction as the wavelength multiplexed signal output from the wavelength group multiplexer.

11. The optical transmission device according to claim 1, further comprising: a second optical signal source that generates an optical signal having a shorter wavelength than the optical signal output from the first optical switch; and second optical multiplexing means that is further configured to multiplex the optical signal having the shorter wavelength and the optical signal output from the first optical switch and to propagate the optical signal having the shorter wavelength in the same direction as the optical signal output from the first optical switch.

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