Patent ID: 7016586

Claim:
A planar waveguide structure having a first core layer, a second core layer and an inter-core cladding layer disposed between a surface of the first core layer and a surface of the second core layer, wherein the inter-core cladding layer comprises a first region having a first refractive index, n inter , and a plurality of sub-regions formed therein having a second refractive index, n sub , said plurality of sub-regions comprising an array in a plane that is parallel to the surfaces of the two core layers wherein each sub-region is enclosed by said first region in said plane and extends perpendicular to said plane but does not extend into the first or the second core layer, the array of sub-regions giving rise to a photonic band structure region, which is effective to perturb an evanescent field of an optical signal propagating through the first and second core layers.