A time domain beam propagation method based on a finite element scheme

A formulation of the time domain beam propagation method based on the finite element method (FETD-BPM) is presented for the first time, so far as the authors are aware. The performance of the FETD-BPM is enhanced by introducing the Pade equation, allowing broadband characterization, and by using perfectly matched layer boundary conditions so as to eliminate spurious reflection from the edges of the analysis region. Specifically the characteristics are analyzed for optical filters using a refractive index-modulated optical grating and a photonic bandgap, and the validity and usefulness of the present method are demonstrated. (C) 1999 Scripta Technica.