Patent ID: 7366422

Claim:
A dispersion compensating device comprising: a virtually imaged phased array (VIPA) plate which is an optical component having two first and second reflecting surfaces that are opposite and parallel to each other, where light that has been converged in one-dimensional direction is incident between said two reflecting surfaces and, while the incident light is being multiply reflected at the two reflecting surfaces, a part of the light is transmitted through said second reflecting surface, and the transmitted light interferes to output substantially linearly dispersed light at an angle that is different depending on a wavelength; a lens that converges the light of each wavelength that is output from said optical component; a mirror having a reflecting surface that reflects the light converged by passing through said lens, where the reflecting surface has a shape capable of giving a constant wavelength dispersion to the light of each wavelength that is output from said optical component with respect to a direction substantially parallel to an angle dispersion direction at said optical component, and a shape capable of giving a different wavelength dispersion to the light of each wavelength that is output from said optical component with respect to a direction substantially perpendicular to the angle dispersion direction at said optical component; and high refractive index side monitor means for monitoring the light that is input into the VIPA plate and emitted from said first reflecting surface.