Optical transmission apparatus, terminal station apparatus, optical communication system, and optical communication method

1. An optical transmission apparatus comprising:

a first multiplexing unit, a plurality of optical signals of different frequencies arranged in a frequency grid being input to the first multiplexing unit, the first multiplexing unit being configured to multiplex the input optical signals;

a dummy light output unit configured to identify one or more dummy lights to be arranged in the frequency grid based on the plurality of optical signals and output the identified one or more dummy lights;

a second multiplexing unit configured to multiplex the plurality of optical signals multiplexed by the first multiplexing unit and the one or more dummy lights output from the dummy light output unit to output a wavelength-multiplexed optical signal; and

a control unit configured to be capable of controlling the dummy light output unit, wherein

the control unit:

receives information indicating ports disposed in the first multiplexing unit respectively corresponding to the plurality of optical signals;

identifies frequencies of the plurality of optical signals based on the information indicating the ports;

identifies frequencies of the one or more dummy lights based on the frequencies of the plurality of optical signals; and

controls the dummy light output unit to output the one or more dummy lights of the identified frequencies.

2. The optical transmission apparatus according to claim 1 , wherein

a signal indicating frequencies of the plurality of optical signals is received, and

frequencies of the one or more dummy lights are identified based on the received signal.

3. The optical transmission apparatus according to claim 1 , further comprising an optical monitor unit configured to monitor intensities of the plurality of optical signals multiplexed by the first multiplexing unit and output a signal indicating a monitoring result to the control unit, wherein

the control unit:

identifies the frequencies of the plurality of optical signals multiplexed by the first multiplexing unit based on the signal indicating the monitor result;

identifies the frequencies of the one or more dummy lights based on the frequencies of the plurality of optical signals; and

controls the dummy light output unit to output the one or more dummy lights of the identified frequencies.

4. The optical transmission apparatus according to claim 1 , wherein, when an optical signal of a frequency different from those of the plurality of optical signals is additionally input to the first multiplexing unit, the dummy light output unit identifies a dummy light corresponding to the frequency of the optical signal to be added from the one or more dummy lights, and stops outputting the identified dummy light.

5. The optical transmission apparatus according to claim 1 , wherein, when there is an optical signal that is blocked not to be input to the first multiplexing unit in the plurality of the optical signals input to the first multiplexing unit, the dummy light output unit identifies a dummy light corresponding to a frequency of the optical signal to be blocked, and newly outputs the identified dummy light.

6. The optical transmission apparatus according to claim 1 , wherein

a plurality of frequency slots having a predetermined width are arranged in the frequency grid, and

in each of the plurality of frequency slots, one optical signal or one dummy light are arranged, or one or more optical signals and one or more dummy lights are arranged without overlapping.

7. A terminal station apparatus comprising:

one or more optical transceivers; and

an optical transmission apparatus in which a plurality of optical signals of different wavelengths are input from the one or more optical transceivers, wherein

the optical transmission apparatus comprises:

a first multiplexing unit, a plurality of optical signals of different frequencies arranged in a frequency grid being input to the first multiplexing unit, the first multiplexing unit being configured to multiplex the input optical signals;

a dummy light output unit configured to identify one or more dummy lights to be arranged in the frequency grid based on the plurality of optical signals and output the identified one or more dummy lights;

a second multiplexing unit configured to multiplex the plurality of optical signals multiplexed by the first multiplexing unit and the one or more dummy lights output from the dummy light output unit to output a wavelength-multiplexed optical signal; and

a control unit configured to be capable of controlling the dummy light output unit, wherein

the control unit:

receives information indicating ports disposed in the first multiplexing unit respectively corresponding to the plurality of optical signals;

identifies frequencies of the plurality of optical signals based on the information indicating the ports;

identifies frequencies of the one or more dummy lights based on the frequencies of the plurality of optical signals; and

controls the dummy light output unit to output the one or more dummy lights of the identified frequencies.

8. The terminal station apparatus according to claim 7 , wherein

a signal indicating frequencies of the plurality of optical signals is received, and

frequencies of the one or more dummy lights are identified based on the received signal.

9. The terminal station apparatus according to claim 7 , further comprising an optical monitor unit configured to monitor intensities of the plurality of optical signals multiplexed by the first multiplexing unit and output a signal indicating a monitoring result to the control unit, wherein

the control unit:

identifies the frequencies of the plurality of optical signals multiplexed by the first multiplexing unit based on the signal indicating the monitor result;

identifies the frequencies of the one or more dummy lights based on the frequencies of the plurality of optical signals; and

controls the dummy light output unit to output the one or more dummy lights of the identified frequencies.

10. The terminal station apparatus according to claim 7 , wherein, when an optical signal of a frequency different from those of the plurality of optical signals is additionally input to the first multiplexing unit, the dummy light output unit identifies a dummy light corresponding to the frequency of the optical signal to be added from the one or more dummy lights, and stops outputting the identified dummy light.

11. The terminal station apparatus according to claim 7 , wherein, when there is an optical signal that is blocked not to be input to the first multiplexing unit in the plurality of the optical signals input to the first multiplexing unit, the dummy light output unit identifies a dummy light corresponding to a frequency of the optical signal to be blocked, and newly outputs the identified dummy light.

12. The terminal station apparatus according to claim 7 , wherein

a plurality of frequency slots having a predetermined width are arranged in the frequency grid, and

in each of the plurality of frequency slots, one optical signal or one dummy light are arranged, or one or more optical signals and one or more dummy lights are arranged without overlapping.

13. An optical communication system comprising:

a first terminal station configured to output a wavelength-multiplexed optical signal; and

a second terminal station configured to receive the wavelength-multiplexed optical signal, wherein

the first terminal station comprises:

one or more optical transceivers; and

an optical transmission apparatus in which a plurality of optical signals of different wavelengths are input from the one or more optical transceivers, wherein

the optical transmission apparatus comprises:

a first multiplexing unit, a plurality of optical signals of different frequencies arranged in a frequency grid being input to the first multiplexing unit, the first multiplexing unit being configured to multiplex the input optical signals;

a dummy light output unit configured to identify one or more dummy lights to be arranged in the frequency grid based on the plurality of optical signals and output the identified one or more dummy lights;

a second multiplexing unit configured to multiplex the plurality of optical signals multiplexed by the first multiplexing unit and the one or more dummy lights output from the dummy light output unit to output a wavelength-multiplexed optical signal; and

a control unit configured to be capable of controlling the dummy light output unit, wherein

the control unit:

receives information indicating ports disposed in the first multiplexing unit respectively corresponding to the plurality of optical signals;

identifies frequencies of the plurality of optical signals based on the information indicating the ports;

identifies frequencies of the one or more dummy lights based on the frequencies of the plurality of optical signals; and

controls the dummy light output unit to output the one or more dummy lights of the identified frequencies.

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

a signal indicating frequencies of the plurality of optical signals is received, and

frequencies of the one or more dummy lights are identified based on the received signal.

15. The optical communication system according to claim 13 , further comprising an optical monitor unit configured to monitor intensities of the plurality of optical signals multiplexed by the first multiplexing unit and output a signal indicating a monitoring result to the control unit, wherein

the control unit:

identifies the frequencies of the plurality of optical signals multiplexed by the first multiplexing unit based on the signal indicating the monitor result;

identifies the frequencies of the one or more dummy lights based on the frequencies of the plurality of optical signals; and

controls the dummy light output unit to output the one or more dummy lights of the identified frequencies.

16. The optical communication system according to claim 13 , wherein, when an optical signal of a frequency different from those of the plurality of optical signals is additionally input to the first multiplexing unit, the dummy light output unit identifies a dummy light corresponding to the frequency of the optical signal to be added from the one or more dummy lights, and stops outputting the identified dummy light.

17. The optical communication system according to claim 13 , wherein, when there is an optical signal that is blocked not to be input to the first multiplexing unit in the plurality of the optical signals input to the first multiplexing unit, the dummy light output unit identifies a dummy light corresponding to a frequency of the optical signal to be blocked, and newly outputs the identified dummy light.