A low-truncation-error scheme for a step-index profile is applied to analysis of a three-dimensional waveguide with the aid of the alternating-direction implicit method. The propagation constants of a single and a coupled rib waveguide are analyzed by use of the imaginary distance procedure. A fast convergence rate, which is not obtainable with the conventional second-order schemes, is realized, leading to highly accurate evaluation of the coupling length. A reduction in discretization error is also demonstrated in the beam-propagation analysis of a tilted rib-waveguide coupler.
© 2000 Optical Society of America
Junji Yamauchi, Toshiyuki Murata, and Hisamatsu Nakano, "Semivectorial H-field analysis of rib waveguides by a modified beam-propagation method based on the generalized Douglas scheme," Opt. Lett. 25, 1771-1773 (2000)