Patent ID: 7209662

Claim:
A wavelength multiplex transmission device, comprising: a block band unit for subjecting a plurality of signal lights of different wavelengths to dispersion compensation on a band basis and outputting the compensated signal lights, a continuous wave light output unit outputting a continuous wave light which supplements power of each said compensated signal light and outputting a continuous wave light signal, a band multiplexing unit, connected to input i) the compensated signal lights output from the block band unit and ii) the continuous wave light signal output from the continuous wave light output unit, the band multiplexing unit multiplexing all the inputted compensated signal light output from said block band unit together with the continuous wave light output from said continuous wave light output unit, and a total band optical amplifier for amplifying all the signal lights multiplexed by the band multiplexing unit in the lump and transmitting the amplified signal lights to a transmission path, wherein, said block band unit includes for each said band: and individual dispersion compensating unit for subjecting each signal light to dispersion compensation, wherein said individual dispersion compensating unit includes: a first dispersion compensating fiber for conducting dispersion compensation with an amount of compensation differing with each signal, and a channel optical amplifier for compensating for a pass loss of each signal light at the first dispersion compensating fiber and output the compensated signal light, and a first optical attenuator for adjusting power level of each signal light output from the channel optical amplifier, a wavelength multiplexing unit for multiplexing all the signal lights subjected to dispersion compensation by the individual compensating unit, and a block dispersion compensating unit for subjecting all the signal lights multiplexed by the wavelength multiplexing unit to dispersion compensation, said block dispersion compensating unit including: a second dispersion compensating fiber for subjecting all the signal lights multiplexed by said wavelength multiplexing unit to dispersion compensation, a band optical amplifier for compensating for a pass loss of all the signal lights at the second dispersion compensating fiber and outputting the compensated signal lights, and a second optical attenuator for adjusting power level of all the signal lights output from the band optical amplifier, and, wherein so as to have power of each signal light output from said band optical amplifier fixed regardless of the number of the signal lights, said second optical attenuator has attenuation adjusted according to attenuation of said first optical attenuator.