Perfectly matched layer (PML) boundary conditions are incorporated into the full-vectorial beam propagation method (BPM) based on a finite element scheme for the three-dimensional (3-D) anisotropic optical waveguide analysis. In the present approach, edge elements based on linear-tangential and quadratic-normal vector basis functions are used for the transverse field components. To show the validity and usefulness of this approach, numerical examples are shown for Gaussian beam propagation in proton-exchanged LiNbO3 optical waveguides. Numerical accuracy of the present PML boundary condition is investigated in detail by comparing the results with those of the conventional absorbing boundary condition (ABC).
Kunimasa Saitoh and Masanori Koshiba, "Full-Vectorial Finite Element Beam Propagation Method with Perfectly Matched Layers for Anisotropic Optical Waveguides," J. Lightwave Technol. 19, 405- (2001)