M. Lohmeyer et al., Phase-matched rectangular magnetooptic waveguides for applications in integrated optics isolators: numerical assessment, OPT COMMUN, 158(1-6), 1998, pp. 189-200
Phase matching between the fundamental TE and TM modes is an essential cond
ition for complete polarization rotation in magnetooptic waveguides with lo
ngitudinally directed magnetization. This condition can be satisfied with e
mbedded square waveguides or with raised strip waveguides, provided that th
e core dimensions are suitably chosen. Based on coupled mode theory for the
vectorial modes of rectangular isotropic waveguides, we numerically simula
te the performance of such devices in an experimental isolator setup, inclu
ding birefringence and optical absorption. Fabrication tolerances with resp
ect to all relevant parameters can be evaluated by simple perturbational ex
pressions. Numerical verification shows that these formulas are accurate en
ough for practical purposes. The tolerances qualify the traditional polariz
ation rotator setup as competitive to recent proposals for integrated optic
al isolators based on nonreciprocal interferometry. (C) 1998 Elsevier Scien
ce B.V. All rights reserved.