Patent ID: 6956700

Claim:
A wavelength dispersion compensating apparatus, comprising: an optical component having two mutually parallel reflective surfaces, in which a light condensed in the one-dimensional direction is incident between said reflective surfaces, and a part of said incident light is transmitted through one of said reflective surfaces while said incident light being multiple-reflected on the reflective surfaces, so that lights dispersed, due to interference by said transmitted light, in a substantially linear direction at different angles according to wavelengths are output; a lens which condenses the lights of respective wavelengths output from the optical component; a mirror having a reflective surface which reflects the lights which have passed through the lens to be condensed, in which said reflective surface has a shape capable to give constant wavelength dispersion to the lights of respective wavelengths output from said optical component, in a direction substantially parallel to a direction of angular dispersion in said optical component, and also capable to give different wavelength dispersion to the lights of respective wavelengths output from said optical component, in a direction substantially perpendicular to the direction of angular dispersion in said optical component; and a slide mechanism which slides said mirror in the direction substantially perpendicular to the direction of angular dispersion in said optical component, to vary the wavelength dispersion to be given to the lights of respective wavelengths output from said optical component according to a sliding amount of said mirror, wherein said wavelength dispersion compensating apparatus further comprises: a variable dispersion diffraction grating disposed between said optical component and said lens, which is capable to disperse the lights output from said optical component in different angles according to wavelengths, and also capable to change an amount of the angular dispersion, in the direction substantially perpendicular to the direction of angular dispersion in said optical component; and a rotation mechanism which rotates said lens and said mirror integrally about a reference point on said variable dispersion diffraction grating according to a diffraction angle in said variable dispersion diffraction grating, and wherein wavelength dispersion slope is varied independently of the wavelength dispersion, according to an angular dispersion amount of said variable dispersion diffraction grating and a rotation amount of said rotation mechanism.