Patent ID: 7046930

Claim:
An optical communication system for performing Wavelength Division Multiplexing (WDM) optical communication, comprising: (a) an optical reception device comprising: Bit Error Rate (BER) measurement means for measuring BERs of individual optical signals with different wavelengths that are received from a sending end, and BER transmission means for transmitting BER information back to the sending end; and (b) an optical transmission device disposed at the sending end, comprising: wavelength assignment means for assigning each wavelength for optical signals to at least one of high Quality-of-Service (QoS) communication and low QoS communication, wavelength-assignment exchanging means for identifying, based on the BER information, wavelengths in the high QoS communication with high BERs and exchanging the identified wavelengths having the high BERs with an equal number of wavelengths having low BERs in the low QoS communication, unless the wavelengths having the high BERs in the high QoS communication outnumber the low BERs being used for the low QoS communication, and optical signal transmission means for multiplexing the wavelengths to transmit the optical signals.