Modeling and Numerical Analysis for Silicon-on-Insulator Rib Waveguide Corners

Silicon-on-insulator (SOI) waveguide designs have shown merit in highly integrated photonic devices and the associated manufacturing technique has achieved an acceptable level of maturity in the microphotonic industry. Thus, the sharp bending of SOI waveguides and/or deflection of light between SOI waveguides are the considerable interest for practical integrated SOI components. In this paper, a theoretical model is proposed for studying a variety of SOI rib waveguide corner mirror structures. Using the model, the precise positioning of the reflector is first studied, then the minimum acceptable reflector length and width are analyzed, and finally an effective reflecting interface (ERI) is found and determined by considering Goos-Hanchen effect. After being optimized with respect to the parameters: dimension (the length and width), position, surface roughness and tilt angle of mirror plane, and material refractive index of reflector, and their relations, the transfer efficiency of the corner mirror can achieve over 96% and 92% at the mirror-plane tilt-angles of respective 0deg and 1deg over a wide range of the corner angles of 80-120deg even accounting for the 100-Aring surface roughness of reflector is considered. The results of the model are validated via a full simulation using the commercial software tool: OptiFDTD.