Patent ID: 8169703
Filing Date: 2012-05-01
Classification: G02B

Abstract:
1. An optical apparatus comprising: a first diffraction grating formed on or within a grating substrate and comprising a first set of diffractive elements that are substantially straight and substantially parallel to one another and that are characterized by a first grating wavevector; and a second diffraction grating formed on or within the same grating substrate as the first diffraction grating and comprising a second set of diffractive elements that are substantially straight, substantially parallel to one another, and not parallel to the diffractive elements of the first set, and that are characterized by a second grating wavevector that is not parallel to the first grating wavevector, wherein: the first diffraction grating is arranged on or within the grating substrate so as to diffract as a freely propagating optical beam and disperse spatially according to wavelength at least a first portion of an optical signal incident as a freely propagating optical beam on the first diffraction grating at an input incidence angle; the second diffraction grating is arranged on or within the grating substrate so as to diffract as a freely propagating optical beam and disperse spatially according to wavelength at least a second portion of the optical signal incident as a freely propagating optical beam on the second diffraction grating at the input incidence angle; and the first and second diffraction gratings are arranged on or within the grating substrate so that the first and second diffracted portions of the optical signal are dispersed along corresponding first and second dispersion directions that are not parallel to one another.