Eficient Finite Element Modelling of Optical Waveguides with Arbitrary Curved Interfaces

Abstract

In this paper an efficient numerical approach based on the finite element method to analyse optical waveguides with smooth and arbitrary shaped dielectric interfaces is reported. Our strategy combines three numerical aspects: an efficient refinement, an efficient sparse matrix solvers, and proper boundary conditions. The adaptive mesh refinement algorithm takes into account simple first order linear (straight sided) triangles which produces high global accuracy instead of resorting to quadratic curve triangles. The effectiveness of the present scheme has been checked by computing the modes and correspondent birefringency of elliptical core fibers reported in the literature. Also, a symmetric 2x2 fused-fiber coupler is analysed pointing out critical geometric parameters in the design of this structure.