An investigation of the mode characteristics of SOI submicron rib waveguides using the film mode matching method

The mode characteristics of SOI (silicon-on-insulator) submicron rib waveguides are very different from those of micrometer-sized ones. Using the full-vector film mode matching method, we propose a simple criterion to determine whether a waveguide mode is guided or not. The single-mode condition for deep-etched waveguides is obtained using this criterion. We also obtain the inherent TM mode leakage and sharp cancelation effects due to TE-TM mode coupling in shallow-etched rib waveguides from numerical simulations, which agree well with the analytical results based on total internal reflection and interference theories.

National Natural Science Foundation of China 60577044 Ministry of Science and Technology '973' Plan 2006CB302803 2007CB613405 Ministry of Science and Technology 2006AA032424 This work was supported in part by the National Natural Science Foundation of China (Grant No. 60577044), the Ministry of Science and Technology '973' Plan (Grant Nos 2006CB302803 and 2007CB613405), and the Ministry of Science and Technology '863' plan (Grant No. 2006AA032424). The authors are grateful to Ladislav Prkna from Charles University and the Academy of Sciences of the Czech Republic, Prague, for his supply of the code of FMM mode solver, and Photon Design Corp., Oxford, UK, for their technical support in the use of their software.