Patent ID: 8615167

Claim:
A WDM optical transmission system comprising: a plurality of optical add/drop multiplexer nodes optically coupled by a transmission line; and a first processor and a second processor provided with two adjacent optical add/drop multiplexer nodes respectively among the plurality of optical add/drop multiplexer nodes, wherein the first processor is operative to control a power level corresponding to each channel of WDM light for a unit section between the two adjacent add/drop multiplexer nodes, and the second processor is operative to calculate an amount of adjustment of a reception level capable of increasing an optical signal-to-noise ratio for each channel of the WDM light reaching the optical add/drop multiplexer node positioned at a receiving end of the unit section based on information on amplification operation of the WDM light in at least one optical-amplification repeating node disposed on the optical transmission line in the unit section, and to adjust a power level corresponding to each channel of the WDM light transmitted on the transmission line from the optical add/drop multiplexer node positioned at a transmission end of the unit section in accordance with a calculation result calculated by the second processor.