Analysis and design of semileaky-type thin-film optical waveguide isolator

This paper describes an optical waveguide isolator that utilizes the unidirectional guided-radiation mode coupling in a magnetooptic/anisotropic slab guide. The basic structure is the semileaky-type waveguide that has been previously used as a polarization mode filter. Specific features of the proposed device are its compact one-section form resulting from the inherent polarization-discrimination property and the relaxed dimensional tolerance due to the automatic phase-matching of coupled modes. Design data and a related discussion are given for the example of LiNbO3/YIG/GGG layered structure operating in the 1.15-μm-wavelength region.