Optical relay device, optical communication system, optical relay method, and storage medium

1. An optical relay device comprising:

an optical brancher unit that receives a wavelength multiplexed optical signal;

a controller unit that specifies a first wavelength and outputs notification information;

a wavelength selector switch that selects an optical signal having the first wavelength from the received wavelength multiplexed optical signal, applies intensity-modulation in accordance with the notification information to the selected optical signal by filtering light power of the optical signal having the first wavelength in accordance with the notification information, adds the intensity-modulated optical signal back to the wavelength multiplexed optical signal, and outputs the wavelength multiplexed optical signal; and

a light output source that generates dummy light having a wavelength, being different from the first wavelength, for compensating for a change in optical intensity of the optical signal having the first wavelength due to the filtering, and outputs the dummy light to the wavelength selector switch.

2. The optical relay device according to claim 1 , wherein the wavelength selector switch includes a variable optical attenuator which attenuates light power of the optical signal having the specified wavelength in accordance with the notification information.

3. The optical relay device according to claim 1 , wherein the controller unit outputs notification information for indicating a state of the optical relay device.

4. The optical relay device according to claim 1 , wherein the controller unit specifies the first wavelength in accordance with a control signal input from an external source.

5. The optical relay device according to claim 1 , wherein the brancher unit branches the received wavelength multiplexed optical signal and outputs one of the wavelength multiplexed optical signals to an external destination and the other to the wavelength selector switch.

6. The optical relay device according to claim 1 , wherein

the wavelength multiplexed optical signal is a combination of an optical signal having a second wavelength to which intensity-modulation in accordance with control information is applied and a plurality of optical signals having wavelengths different from the second wavelength;

the wavelength selector switch extracts an optical signal having the second wavelength from the received wavelength multiplexed optical signal based on an input control signal; and

the controller unit acquires the control information from the extracted optical signal having the second wavelength and performs predetermined control based on the acquired control information.

7. The optical relay device according to claim 6 , wherein

the control information is information that specifies the first wavelength; and

the controller unit specifies the first wavelength based on the acquired control information.

8. The optical relay device according to claim 1 , wherein the controller unit outputs notification information for indicating a state of the optical relay device.

9. The optical relay device according to claim 1 , wherein the controller unit specifies the first wavelength in accordance with a control signal input from an external source.

10. The optical relay device according to claim 1 , wherein the optical brancher unit branches the received wavelength multiplexed optical signal and outputs one of the wavelength multiplexed optical signals to an external destination and the other to the wavelength selector switch.

11. The optical relay device according to claim 1 , wherein

the wavelength multiplexed optical signal is a combination of an optical signal having a second wavelength to which intensity-modulation in accordance with control information is applied and a plurality of optical signals having wavelengths different from the second wavelength;

the wavelength selector switch extracts an optical signal having the second wavelength from the received wavelength multiplexed optical signal based on an input control signal; and

the controller unit acquires the control information from the extracted optical signal having the second wavelength and performs predetermined control based on the acquired control information.

12. An optical communication system comprising an optical transmitter and an optical relay device,

the optical transmitter comprising:

a plurality of transmitter units that outputs optical signals having different wavelengths, the optical signals being available for data communication;

a transmitting-side wavelength selector switch that multiplexes the plurality of output optical signals into a wavelength multiplexed optical signal and transmits the wavelength multiplexed optical signal; and

a transmitting-side controller unit that specifies a second wavelength and outputs control information;

the optical relay device comprising:

an optical brancher unit that receives the wavelength multiplexed optical signal;

a receiving-side controller unit that specifies a first wavelength and outputs notification information; and

a receiving-side wavelength selector switch that selects an optical signal having the first wavelength from the received wavelength multiplexed optical signal, applies intensity-modulation in accordance with the notification information to the selected optical signal, adds the intensity-modulated optical signal back to the wavelength multiplexed optical signal, outputs the wavelength multiplexed optical signal, and extracts the optical signal having the second wavelength from the received wavelength multiplexed optical signal,

wherein the receiving-side controller unit acquires the control information from the extracted optical signal having the second wavelength and performs predetermined control based on the acquired control information.

13. The optical communication system according to claim 12 , wherein

the transmitting-side unit outputs control information for controlling the optical relay device; and

the receiving-side controller unit outputs notification information for indicating a state of the optical relay device.

14. The optical communication system according to claim 12 , further comprising a controller which transmits a control signal for specifying the second wavelength, wherein

the transmitting-side controller unit and the receiving-side wavelength selector switch identify the second wavelength in accordance with the received control signal; and

the receiving-side controller unit identifies the first wavelength based on the acquired control information.

15. An optical relay method comprising:

receiving a wavelength multiplexed optical signal; specifying a first wavelength and outputting notification information;

selecting an optical signal having the first wavelength from the received wavelength multiplexed optical signal, applying intensity-modulation by filtering in accordance with the notification information to the selected optical signal, adding the intensity-modulated optical signal back to the wavelength multiplexed optical signal and outputting the wavelength multiplexed optical signal;

generating dummy light having a wavelength, being different from the first wavelength, for compensating for a change in optical intensity of the optical signal having the first wavelength due to the filtering; and outputting the dummy light.

16. An optical relay device comprising:

an optical brancher unit that receives a wavelength multiplexed optical signal;

a controller unit that specifies a first wavelength and outputs notification information;

a wavelength selector switch that selects an optical signal having the first wavelength from the received wavelength multiplexed optical signal, applies intensity-modulation in accordance with the notification information to the selected optical signal by filtering light power of the optical signal having the first wavelength in accordance with the notification information, adds the intensity-modulated optical signal back to the wavelength multiplexed optical signal, and outputs the wavelength multiplexed optical signal, wherein the wavelength selector switch includes a variable optical attenuator which attenuates light power of the optical signal having the specified wavelength in accordance with the notification information; and

a light output source that generates dummy light having a wavelength, being different from the first wavelength, for compensating for a change in optical intensity of the optical signal having the first wavelength due to the filtering, and outputs the dummy light to the wavelength selector switch.