Patent ID: 6943940

Claim:
An optical communication system comprising: a plurality of transmitters transmitting lights at different wavelengths, respectively; a multiplexer multiplexing the lights at different wavelengths together into a WDM light, and providing the WDM light to an optical transmission line; a plurality of optical amplifiers arranged along the transmission line to amplify the WDM light traveling through the transmission line; a demultiplexer demultiplexing the WDM light transmitted through the transmission line and the plurality of optical amplifiers into the lights at different wavelengths; and a plurality of receivers receiving the lights demultiplexed by the demultiplexer, wherein the plurality of optical amplifiers include a first-type optical amplifier and a second-type optical amplifier, the first-type optical amplifier includes a first amplification stage demultiplexing the WDM light into first and second lights, separately amplifying the first and second lights, and multiplexing the amplified first and second lights together into a multiplexed light, a dispersion compensator compensating for dispersion in the multiplexed light, and a second amplification stage demultiplexing the dispersion compensated, multiplexed light into the first and second lights, separately amplifying the demultiplexed first and second lights, and multiplexing the separately amplified first and second lights into a WDM light which is provided to the transmission line, and the second-type optical amplifier includes a demultiplexer demultiplexing the WDM light into the first and second lights, a first amplification stage amplifying the demultiplexed first light, providing dispersion compensation to the amplified first light, and amplifying the dispersion compensated first light, to output a first stage light, a second amplification stage amplifying the demultiplexed second light, providing dispersion compensation to the amplified second light, and amplifying the dispersion compensated second light, to output a second stage light, and a multiplexer multiplexing the first and second stage lights together into a WDM light provided to the optical transmission line.