Patent ID: 7499620

Claim:
A low loss optical waveguiding structure disposed on a top surface of a silicon-on-insulator (SOI) wafer comprising a silicon substrate, a buried dielectric layer and a relatively thin silicon surface waveguiding layer disposed over the buried dielectric layer, the low loss optical waveguiding structure comprising a relatively thin dielectric layer disposed over at least a portion of the relatively thin silicon surface waveguiding layer; and a silicon waveguiding structure disposed over at least a portion of the relatively thin dielectric layer, the combination of the contiguous portions of the relatively thin silicon surface waveguiding layer, the relatively thin dielectric layer and the silicon waveguiding structure forming an optical waveguiding region, wherein both the relatively thin silicon surface waveguiding layer and the silicon waveguiding structure are defined as exhibiting at least one rounded edge in the waveguiding region to reduce optical loss in the optical waveguiding structure.