Modeling the impact of imperfections in high-index-contrast photonic waveguides

By formulating Maxwell's equations in perturbation-matched curvilinear coordinates, we have derived rigorous perturbation theory (PT) and coupled-mode theory expansions that are applicable in the case of generic nonuniform dielectric profile perturbations in high-index-contrast waveguides, including photonic band gap fibers, and two-dimensional (2D) and 3D waveguides. PT is particularly useful in the optimization stage of a component design process where fast evaluation of an optimized property with changing controlling variables is crucial. We demonstrate our method by studying radiation scattering due to common geometric variations in planar 2D photonic crystals waveguides.