Multi-wavelength optical modulation circuit and wavelength-division multiplexed optical signal transmitter

A wavelength-division multiplexed optical signal transmitter, comprising:

• a multi-wavelength generation light source that generates multi-wavelength light having a plurality of wavelengths;
• and
• a multi-wavelength optical modulation circuit,
• wherein the multi-wavelength optical modulation circuit is provided with:
• a wavelength-group demultiplexer that receives the multi-wavelength light to demultiplex the multi-wavelength light into wavelength groups formed from the respective plurality of wavelengths;
• a plurality of channel demultiplexers that demultiplex each wavelength group into light of the respective wavelengths;
• a plurality of optical modulators that modulates the light of each wavelength demultiplexed by the channel demultiplexers with transmission signals;
• a plurality of channel multiplexers that multiplex the modulated signal light of each wavelength output from the plurality of optical modulators for each wavelength group;
• and
• a wavelength-group multiplexer that multiplexes the wavelength-division multiplexed signal light of each wavelength group output from each channel multiplexer,
• wherein a frequency band of the multi-wavelength light is equal to or greater than free spectral ranges of the channel demultiplexers and the channel multiplexers,
• the wavelength-group demultiplexers and the wavelength-group multiplexers have free spectral ranges equal to or greater than the frequency band in which the multi-wavelength light output from the multi-wavelength generation light source is located, and
• the channel demultiplexers and the channel multiplexers have free spectral ranges that correspond to a difference in transmission center frequencies between ports of the wavelength-group demultiplexer and the wavelength-group multiplexer where wavelengths are adjacent.

A multi-wavelength optical modulation circuit, comprising:

• a wavelength-group demultiplexer that receives amplified spontaneous emission light and demultiplexes the amplified spontaneous emission light into wavelength groups formed from a respective plurality of wavelengths;
• a plurality of channel demultiplexers that demultiplex each wavelength group into light of the respective wavelengths;
• a plurality of optical modulators that modulate the light of respective wavelengths demultiplexed by the channel demultiplexers with transmission signals;
• a plurality of channel multiplexers that multiplex and modulated signal light of each wavelength output from the optical modulators for each wavelength group;
• and
• a wavelength-group multiplexer that multiplexes the wavelength-division multiplexed signal light of each wavelength group output from each channel multiplexer,
• wherein a frequency band of the amplified spontaneous emission light is equal to or greater than free spectral ranges of the channel demultiplexers and the channel multiplexers,
• the wavelength-group demultiplexer and the wavelength-group multiplexer have free spectral ranges equal to or greater than the frequency band of the amplified spontaneous emission light, and
• the channel demultiplexers and the channel multiplexers have free spectral ranges that correspond to a difference in transmission center frequencies between ports of the wavelength-group demultiplexer and the wavelength-group multiplexer where wavelengths are adjacent.

A wavelength-division multiplexed optical signal transmitter, comprising:

• a polarization maintain optical fiber amplifier input of which is optically terminated and that outputs amplified spontaneous emission light;
• and
• a multi-wavelength optical modulation circuit,
• wherein the multi-wavelength optical modulation circuit is provided with:
• a wavelength-group demultiplexer that receives the amplified spontaneous emission light to demultiplex the amplified spontaneous emission light into wavelength groups formed from a respective plurality of wavelengths;
• a plurality of channel demultiplexers that demultiplex each wavelength group into light of the respective wavelengths;
• a plurality of optical modulators that modulate the light of each wavelength demultiplexed by the channel demultiplexers with transmission signals;
• a plurality of channel multiplexers that multiplex the modulated signal light of each wavelength output from the plurality of optical modulators for each wavelength group;
• and
• a wavelength-group multiplexer that multiplexes the wavelength-division multiplexed signal light of each wavelength group output from each channel multiplexer,
• wherein a frequency band of the amplified spontaneous emission light is equal to or greater than free spectral ranges of the channel demultiplexers and the channel multiplexers,
• the wavelength-group demultiplexers and the wavelength-group multiplexers have free spectral ranges equal to or greater than the frequency band in which the amplified spontaneous emission light output from the polarization maintain optical fiber amplifier is located, and
• the channel demultiplexers and the channel multiplexers have free spectral ranges that correspond to a difference in transmission center frequencies between ports of the wavelength-group demultiplexer and the wavelength-group multiplexer where wavelengths are adjacent.