Nonlinear FDTD method for the simulation of the optical effects in silicon waveguides

Abstract

As the interest for Silicon-On-Insulator (SOI) waveguides is increasing, it would be valuable to have an explicit simulation method to provide a framework for quick and low cost analysis of the optical effects in silicon waveguides. This paper focuses on modeling the inherent optical properties of silicon waveguides using the finite-difference-time-domain (FDTD) method. Emphasis was placed on nonlinearities which are: Kerr effect, Two Photon Absorption (TPA), Stimulated Raman Scattering, Free Carrier Absorption (FCA) and Free Carrier Plasma (FCP). These effects have been included directly in an extended FDTD simulator through time-dependent Maxwell's equations and using the nonlinear constitutive relation. The objective is to develop a time-domain algorithm for investigating the complex physical phenomena inherited in silicon waveguides before photonic devices are fabricated. The FDTD method is an attractive choice due to its explicit nature which makes the least possible approximations, its simplicity and its accuracy of the results. To check the validity of our simulations, the results have been compared with those shown in the literature.