Patent ID: 6999662
Filing Date: 2006-02-14
Classification: G02B

Abstract:
1. An optical device for filtering an optical signal, comprising: an optical input receiving said optical signal; an elongated waveguide connected to said input and having a transverse dimension modified in abrupt steps so as to create a long sequence of segments, said abrupt steps corresponding to a change in the waveguide transverse dimension occurring along said waveguide in less than one tenth of a wavelength of light in a medium of the waveguide, said abrupt steps defining a plurality of spatially interleaved subsets of sharp optically reflecting interfaces, each one of said subsets having said sharp interfaces placed according to a positioning pattern along the waveguide with an accuracy better than one hundredth of a wavelength in terms of the optical path lengths between interfaces belonging to the same subset, in order to coherently reflect light according to a desired optical spectrum, said spectrum of reflected light occupying spectral regions substantially distinct from the spectral regions where other subsets of said sharp interfaces reflect light, wherein said segments are designed for single transverse mode operation over a full spectral range of interest, wherein a reflected filtered output optical signal is generated, wherein the transverse waveguide dimension varies within a range sufficiently narrow that a mode size remains close to its minimum size and does not deviate by more than five percent over said minimum size for the full optical spectrum; an optical output connected to said waveguide for providing said filtered optical signal.