New fast Fourier transform and finite-element approaches to the calculation of multiple-stripe-geometry laser modes

Abstract

We have developed a new method, based on the split-step fast Fourier transform algorithm, for calculating the modes of a general graded-index active waveguiding structure and demonstrate that the method can be applied to the periodic part of the Bloch function and hence to a strictly periodic multiple-stripe-geometry laser. We also develop a second approach involving the finite-element method.