Mode calculation by beam propagation method combined with digital signal processing technique

A robust computational scheme for calculation of multiple modes of optical waveguides is developed and presented. The new method uses the beam propagation methods to generate the modal fields and a digital signal processing technique for mode parameter extraction. It can be applied to both guided and leaky modes with different formulations (i.e., scalar, semi-vector or full-vector) and discretizations (e.g., finite difference or finite element). Salient features of the new method are discussed and advantages over other computational methods based on boundary-value eigen solvers and initial-value propagation solvers are demonstrated by way of examples.