Abstract

The propagation-beam, or beam-propagation, method has been extensively used to simulate waveguide devices.^1-3 Both three-dimensional (3D) and two-dimensional (2D) calculations have been used. The 2D calculation requires substantially less computer time, however, it uses the effective index, which is an approximation to the real index profile.⁴ The effective-index method has been demonstrated to provide accurate results for single-mode structures. On the other hand, Y junctions are commonly used in waveguide devices. At the branching point, a Y junction may support more than one mode locally. It is interesting to compare 2D and 3D results for waveguide devices with Y junctions.

© 1990 Optical Society of America