ANALYSIS OF Y-BRANCHING OPTICAL CIRCULATOR USING MAGNETOOPTIC MEDIUM AS A SUBSTRATE

A slab-type Y-branching optical circulator is proposed and analyzed. The circulator operation is based on the difference in the propagation constants of the modes with opposite propagation directions in the nonreciprocal waveguide. This circulator uses the magnetooptic material as a substrate of the nonreciprocal waveguide to enhance the difference in the propagation constants. The configuration may reduce the propagation loss due to the absorption of the magnetooptic material. Calculations of the transverse magnetic-field distributions in the waveguide show a circulator property of the Y-branching waveguide. The effect of the magnitude of the magnetooptic activity on the circulator property is discussed.