Patent ID: 8798477

Claim:
A chromatic dispersion monitor for estimating a chromatic dispersion in accordance with a chromatic dispersion correlation amount sequence, comprising: an adaptive filter controlled by filter coefficients; a chromatic dispersion correlation amount calculating unit connected to an output of the adaptive filter and producing the chromatic dispersion correlation amount sequence, wherein the chromatic dispersion correlation amount sequence is obtained based on the filter coefficients of the adaptive filter; a phase differential unit, connected to an output of the chromatic dispersion correlation amount calculating unit and for obtaining a phase difference sequence by performing a phase differential calculation in accordance with the chromatic dispersion correlation amount sequence, the chromatic dispersion correlation amount sequence being an expression in frequency domain for channel transfer function of a monitored channel; a phase difference differential unit, connected to an output of the phase differential unit and for obtaining a phase difference differential sequence by performing a phase difference differential operation; and a chromatic dispersion estimating unit, connected to an output of the phase difference differential unit and for estimating the chromatic dispersion in accordance with the phase difference differential sequence obtained by the phase difference differential unit.