Abstract

Modeling and simulation are important to the optimum design and precise prediction of the possible performance of optical guided-wave devices. One of the commonly used numerical methods for the simulation of wave propagation in optical waveguides is the beam propagation method (BPM)^1,2 and its variations.^3,4 Since all these methods assume Fresnel approximation, the reflection of the waves due to the inhomogeneous perturbations along the waveguiding axis has been neglected. The reflection, however, may not be negligible at abrupt junctions and certainly become dominant in structures such as distributed feedback reflectors. A finite-difference time-domain technique (FDTD) that solves the Maxwell′s equations directly has been recently introduced and in principle can be applied to the structures that both the reflection and the polarization effects become important.⁵ Since most practical optical waveguides are weakly-guiding, the scalar analysis is often sufficient. Therefore, as an alternative approach, we propose to apply FDTD technique to the scalar analysis.

© 1991 Optical Society of America