45° waveguide isolators with phase mismatch

45° waveguide isolators based on magneto-optic channel waveguides with phase mismatch can be realized simply by choosing a proper orientation of the input polarization. This is demonstrated theoretically by visualizing the magneto-optic mode coupling as ‘‘coupling tracks’’ on the Poincaré sphere, and is verified experimentally for real waveguides with considerable phase mismatch. More than 30 dB isolation is feasible in practical devices.