Patent ID: 7016587

Claim:
A method of fabricating a silicon-rib waveguide for a micro-optical device, comprising the steps of: providing a silicon-on-insulator structure having a single crystal silicon wafer surface thereof being bonded to a surface of a silicon wafer with a layer of insulative bonding material; patterning a surface of the single crystal silicon wafer opposite said surface bonded to the surface of the silicon wafer to form at least one silicon rib waveguide, the at least one silicon rib waveguide having a top surface and opposing side walls and end walls; forming a silicon nitride cladding layer on said top surface and said opposing side walls and end walls of the at least one silicon rib, said silicon nitride cladding layer having a predetermined thickness; and determining said predetermined thickness of said silicon nitride cladding layer for the combined use thereof as an anti-reflection coating and as an optical loss reducing layer, said predetermined thickness suitable for such combined use being based upon a multiple of the light wave length (λ) of a light transmitted through said silicon rib waveguide divided by four times the index of refraction (n) of the silicon nitride cladding layer (λ/4n).