Patent ID: 8295659

Claim:
A pixel cell comprising: a photo-conversion device formed in association with a substrate; a plurality of material layers over said substrate; and an anti-resonant reflecting optical waveguide structure formed over said photo-conversion device and within said plurality of material layers, said waveguide structure comprising: a trench within at least a portion of said plurality of material layers; a plurality of cladding structures formed along a sidewall of said trench, said plurality of cladding structures being contiguous with each other along at least the entire length of said trench sidewall; and a core material formed in contact with an innermost one of said plurality of cladding structures and filling a remaining portion of said trench, wherein a refractive index of said core material is lower than a refractive index of the innermost cladding structure and wherein a refractive index of a second cladding structure in contiguous contact with said innermost cladding structure is lower than said refractive index of said innermost cladding structure.