Magnetooptical waveguides having nonreciprocal phase shift for both TE and TM modes can be prepared by properly adjusting the spatial variation of the Faraday rotation. Such waveguides are attractive to realize optical isolators. We investigate four concepts of magnetooptical waveguides which yield equal nonreciprocal phase shifts for the fundamental TE and TM modes. A polarization-independent Mach-Zehnder-type integrated optical isolator is presented. All the calculations are performed using material parameters typical for garnet films.
O. Zhuromskyy, H. tsch, M. Lohmeyer, L. Wilkens, and P. Hertel, "Magnetooptical Waveguides with Polarization-Independent Nonreciprocal PhaseShift," J. Lightwave Technol. 19, 214- (2001)