Patent ID: 8055135

Claim:
A dispersion compensator that compensates dispersion occurring in an optical pulse, said dispersion compensator comprising: a first diffraction grating that extracts a light having a specific wavelength from a light having mixed wavelengths; a collimator lens that converts the light having the specific wavelength extracted by said first diffraction grating into a parallel light beam; a spatial filter from which a pulsed light having a single peak is emitted as an autocorrelation light for a light having a strong correlation with an optical pulse to be dispersion-compensated, and from which a scattered light is emitted as a cross-correlation light for a light having a weak correlation with an optical pulse to be dispersion-compensated, the light having the strong correlation and the light having the weak correlation being included in the lights passing through said collimator lens; a focus lens that focuses the light on which dispersion compensating processing has been performed in said spatial filter; and a second diffraction grating that restores the light focused by said focus lens to the light having the mixed wavelengths, wherein said dispersion compensator compensates dispersion occurring in the optical pulse having the strong correlation with the optical pulse to be dispersion-compensated, with the autocorrelation light treated as a dispersion-compensated optical pulse.