Optical transmission system, optical transmission apparatus and transmission method

1. An optical transmission system, comprising:

a transmission apparatus; and

a reception apparatus, the transmission apparatus and the reception apparatus being interconnected via a first transmission line and a second transmission line, wherein

the transmission apparatus includes:

a first transmitter configured to output a first optical signal having a wavelength belonging to a first wavelength band;

a first switch configured to output the first optical signal being outputted from the first transmitter toward the first transmission line or the second transmission line;

a first wavelength converter configured to convert the first optical signal being outputted from the first switch toward the first transmission line into a second optical signal having a wavelength belonging to a second wavelength band other than the first wavelength band;

a second transmitter configured to output a third optical signal having a wavelength belonging to the first wavelength band;

a first multiplexer configured to multiplex the second optical signal and the third optical signal and output the multiplexed optical signal to the first transmission line; and

a second multiplexer configured to wavelength-multiplex optical signals including the first optical signal outputted from a plurality of first transmitters, and output a multiplexed optical signal to the first switch, and

the reception apparatus includes:

a demultiplexer configured to demultiplex the multiplexed optical signal inputted from the first transmission line into the third optical signal and the second optical signal;

a first receiver configured to receive the third optical signal from the demultiplexer;

a second wavelength converter configured to convert the second optical signal into the first optical signal; and

a second receiver configured to receive the first optical signal that being converted from the second optical signal or the first optical signal received through the second transmission line.

2. An optical transmission apparatus comprising:

a first transmitter configured to output a first optical signal having a wavelength belonging to a first wavelength band;

a switch configured to output the first optical signal being outputted from the first transmitter toward a first transmission line or a second transmission line;

a wavelength converter configured to convert the first optical signal being outputted from the switch toward the first transmission line into a second optical signal having a wavelength belonging to a second wavelength band other than the first wavelength band;

a second transmitter configured to output a third optical signal having a wavelength belonging to the first wavelength band;

a first multiplexer configured to multiplex the second optical signal and the third optical signal, and output a multiplexed optical signal to the first transmission line; and

a second multiplexer configured to wavelength-multiplex optical signals including the first optical signal outputted from a plurality of first transmitters, and output a multiplexed optical signal to the switch.

3. The optical transmission apparatus according to claim 2 , further comprising:

a second multiplexer configured to wavelength-multiplex optical signals including the first optical signal outputted from a plurality of first transmitters via a plurality of switches, and output a multiplexed optical signal to the wavelength converter.

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

the switch outputs the first optical signal toward the second transmission line when the first optical signal having a wavelength with a fault.

5. An optical transmission method comprising:

outputting a first optical signal having a wavelength belonging to a first wavelength band;

wavelength-multiplexing optical signals including the first optical signal outputted from a plurality of first transmitters, and outputting the multiplexed optical signal;

outputting, by a switch, the first optical signal included in the multiplexed optical signal toward a first transmission line or a second transmission line;

converting the first optical signal being outputted toward the first transmission line into a second optical signal having a wavelength in a second wavelength band other than the first wavelength band;

outputting a third optical signal having a wavelength belonging to the first wavelength band; and

multiplexing the second optical signal and the third optical signal, and outputting the multiplexed optical signal to the first transmission line.

6. The optical transmission method according to claim 5 , further comprising:

wavelength-multiplexing the first optical signals outputted toward the first transmission line among a plurality of first optical signals having different wavelengths; and

wavelength-converting a plurality of wavelength-multiplexed first optical signals.

7. The optical transmission method according to claim 5 , further comprising:

wavelength-multiplexing a plurality of first optical signals having different wavelengths, the first optical signals being outputted from a plurality of first transmitters,

outputting the plurality of wavelength-multiplexed first optical signal toward the first transmission line or the second transmission line.

8. The optical transmission method according to claim 5 , wherein

outputting the first optical signal toward the second transmission line when the first optical signal having a wavelength with a fault.