INTEGRATED OPTICAL CIRCULATOR BASED ON RADIATIVELY COUPLED MAGNETOOPTIC WAVE-GUIDES

In a three-guide coupler with multimode central waveguide, more than t wo modes of the entire structure participate in the coupling between t he outer waveguides. Using a three-mode approximation we found simple conditions for complete power transfer between the outer waveguides: t he device length has to match certain multiples of the conventionally defined coupling length. The specific form of the relevant modes allow s us to design a magneto-optic isolator or circulator with significant ly reduced device length (as compared to the conventional nonreciproca l coupler). The performance of the proposed devices is simulated by pr opagating-mode calculations. Estimates for admissible fabrication tole rances for the layer thicknesses are presented. (C) 1997 Society of Ph oto-Optical Instrumentation Engineers.