Patent ID: 7118682
Filing Date: 2006-10-10
Classification: G02F

Abstract:
1. A method of making 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 silicon surface waveguiding layer disposed over the buried dielectric layer, the method comprising the steps of: forming a dielectric layer over at least a portion of the silicon surface waveguiding layer; forming a silicon waveguiding structure over at least a portion of the dielectric layer, the combination of the contiguous portions of the silicon surface waveguiding layer, the dielectric layer and the silicon waveguiding structure forming an optical waveguiding region, at least one of both the silicon surface waveguiding layer and the silicon waveguiding structure defined as exhibiting at least one right-angled edge in the waveguiding region; and rounding the at least one right-angled edge in the optical waveguiding region to reduce optical loss in the optical waveguiding structure by forming a sacrificial silicon layer over the silicon waveguiding structure and processing the sacrificial silicon layer to form rounded edges along the borders of the optical waveguiding region.