Patent ID: 7433599

Claim:
An automatic dispersion compensation device with a variable chromatic dispersion compensator for incoming optical signals input from an optical transmitter transmitting optical signals for a plurality of channels through a transmission line, comprising: a transmission quality measurement unit measuring transmission quality of incoming optical signals for each of the plurality of channels; a determination unit detecting whether the transmission quality is depended upon the optical signal wavelength, and reporting a degradation of the incoming optical signal as a degradation due to a chromatic dispersion if the transmission quality is depended upon the optical signal wavelength; a chromatic dispersion compensation amount control unit controlling the variable chromatic dispersion compensator in such a way as to compensate for the degradation due to the chromatic dispersion if the determination unit reports that the transmission quality is depended upon the optical signal wavelength, wherein if the transmission quality is dependent on an optical signal wavelength, then it is determined that there is chromatic dispersion and compensation is performed, and if the transmission quality is not dependent on the optical signal wavelength then it is determined that there is no chromatic dispersion; and a residual chromatic dispersion amount increase/decrease unit increasing/decreasing the difference in the amount of dispersion compensation between channels for any residual amount of chromatic dispersion obtained as a result of compensation by the variable chromatic dispersion compensator, depending on the optical signal wavelength; and a chromatic dispersion amount increase/decrease judgment unit comparing the measurement result of transmission quality after compensation by the variable chromatic dispersion compensator and the residual chromatic dispersion amount increase/decrease unit, between channels, and judging whether the amount of chromatic dispersion in the transmission line increases or decreases.