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

A formulation of the time domain beam propagation method based on the finit e 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 introduci ng the Pade equation, allowing broadband characterization, and by using per fectly matched layer boundary conditions so as to eliminate spurious reflec tion from the edges of the analysis region. Specifically the characteristic s are analyzed for optical filters using a refractive index-modulated optic al grating and a photonic bandgap, and the validity and usefulness of the p resent method are demonstrated. (C) 1999 Scripta Technica.