Optical signal demultiplexing device, optical signal reception device, and optical signal demultiplexing method

1. An optical demultiplexing device comprising:

a first optical coupler configured to branch an optical signal in which signals having a plurality of wavelength intervals different from one another are multiplexed by the number of wavelength intervals;

a plurality of band division units arranged so as to correspond to each of the plurality of wavelength intervals, the plurality of band division units generating, for each of the wavelength intervals, a band division signal in which a signal band of an optical signal branched by the first optical coupler is divided by a predetermined bandwidth and an odd channel and an even channel are separated from each other in each of the wavelength intervals;

a plurality of multiplexing units arranged, for each of the signal bands that have been divided, so as to correspond to the odd channel and the even channel, the plurality of multiplexing units multiplexing, for each of the signal bands that have been divided, the band division signals, output from the band division units, including odd channels of the respective wavelength intervals, and multiplexing, for each of the signal bands that have been divided, the band division signals including the even channels of the respective wavelength intervals;

a plurality of second optical couplers arranged, for each of the signal bands that have been divided, so as to correspond to the odd channel and the even channel, the plurality of second optical couplers branching each of a multiplexed signal including odd channels of the respective wavelength intervals multiplexed by using each of the multiplexing units and a multiplexed signal including even channels of the respective wavelength intervals into a plurality of communication devices; and

a controller configured to control the band division units,

wherein each of the plurality of band division units includes a wavelength selective switch, and

wherein the controller controls the wavelength selective switch based on information indicating a signal arrangement of the signals in the respective wavelength intervals in the optical signal, causes the wavelength selective switch to output a signal of a wavelength band in which a signal of a corresponding wavelength interval is present to the multiplexing units, and causes the wavelength selective switch to cut off a signal of a wavelength band in which a signal of the corresponding wavelength interval is not present.

2. The optical demultiplexing device according to claim 1 , wherein each of the plurality of band division units further includes an interleaver separating the odd channel and the even channel in each of the wavelength intervals.

3. The optical demultiplexing device according to claim 2 , wherein each of the plurality of band division units includes first and second wavelength selective switches, the first wavelength selective switch dividing an optical signal including the odd channels separated using the interleaver by the predetermined bandwidth, and the second wavelength selective switch dividing an optical signal including the even channels separated using the interleaver by the predetermined bandwidth.

4. The optical demultiplexing device according to claim 3 , wherein the first and second wavelength selective switches included in each of the plurality of band division units respectively comprise a first port optically coupled to an output of the interleaver and second ports that correspond to the number of signal bands to be divided.

5. The optical demultiplexing device according to claim 1 , wherein the wavelength selective switch included in each of the plurality of the band division units also functions as an interleaver that separates the odd channel and the even channel.

6. The optical demultiplexing device according to claim 5 , wherein each of the plurality of wavelength selective switches comprises a first port optically coupled to an output of the first optical coupler, second ports the number of which corresponds to the number of signal bands to be divided, and third ports the number of which corresponds to the number of signal bands to be divided, the plurality of wavelength selective switches outputting, from each of the second ports, an optical signal having a wavelength that corresponds to the odd channel, the optical signal having been divided by the predetermined bandwidth, and the plurality of wavelength selective switches outputting, from each of the third ports, an optical signal having a wavelength that corresponds to the even channel, the optical signal having been divided by the predetermined bandwidth.

7. The optical demultiplexing device according to claim 1 , wherein the wavelength selective switch included in each of the plurality of band division units divides the optical signal into signal bands whose boundary wavelength is a wavelength in which a signal is not present in each of the signals in which the odd channels and the even channels in the respective wavelength intervals are separated from each other.

8. An optical signal reception device comprising:

a first optical coupler configured to branch an optical signal in which signals having a plurality of wavelength intervals different from one another are multiplexed by the number of wavelength intervals;

a plurality of band division units arranged so as to correspond to each of the plurality of wavelength intervals, the plurality of band division units generating, for each of the wavelength intervals, a band division signal in which a signal band of an optical signal branched by the first optical coupler is divided by a predetermined bandwidth and an odd channel and an even channel are separated from each other in each of the wavelength intervals;

a plurality of multiplexing units arranged, for each of the signal bands that have been divided, so as to correspond to the odd channel and the even channel, the plurality of multiplexing units multiplexing, for each of the signal bands that have been divided, the band division signals, output from the band division units, including odd channels of the respective wavelength intervals, and multiplexing, for each of the signal bands that have been divided, the band division signals including the even channels of the respective wavelength intervals;

a plurality of second optical couplers arranged, for each of the signal bands that have been divided, so as to correspond to the odd channel and the even channel, the plurality of second optical couplers branching each of a multiplexed signal including odd channels of the respective wavelength intervals multiplexed by using each of the multiplexing units and a multiplexed signal including even channels of the respective wavelength intervals into a plurality of communication devices;

a controller configured to control the band division means; and

an optical receiver configured to receive the multiplexed signals branched by the second optical coupler,

wherein each of the plurality of band division units includes a wavelength selective switch, and

wherein the controller controls the wavelength selective switch based on information indicating a signal arrangement of the signals in the respective wavelength intervals in the optical signal, causes the wavelength selective switch to output a signal of a wavelength band in which a signal of a corresponding wavelength interval is present to be output to the multiplexing units, and causes the wavelength selective switch to cut off a signal of a wavelength band in which a signal of the corresponding wavelength interval is not present.

9. An optical demultiplexing method comprising:

branching an optical signal in which signals having a plurality of wavelength intervals different from one another are multiplexed by the number of wavelength intervals;

generating, for each of the optical signals that have been branched, a band division signal in which a signal band of an optical signal that has been branched is divided by a predetermined bandwidth and an odd channel and an even channel are separated from each other in each of the wavelength intervals;

multiplexing, for each of the signal bands that have been divided, a band division signals including odd channels of the respective wavelength intervals;

multiplexing, for each of the signal bands that have been divided, a band division signals including even channels of the respective wavelength intervals; and

branching each of a multiplexed signal including odd channels of the respective wavelength intervals multiplexed and a multiplexed signal including even channels of the respective wavelength intervals into a plurality of communication devices, wherein when the band division signal is generated, a wavelength selective switch is controlled based on information indicating a signal arrangement of the signals in the respective wavelength intervals in the optical signal, thereby causing a signal of a wavelength band in which a signal of a corresponding wavelength interval is present to be included in the band division signal, and causing a signal of a wavelength band in which a signal of the corresponding wavelength interval is not present to be cut off by the wavelength selective switch.