LIGHT-PROPAGATION IN A PLANAR DIELECTRIC WAVE-GUIDE WITH A GYROTROPICLAYER

The nature of the magneto-optic Kerr effect in a planar dielectric wav eguide geometry has been investigated by calculation of the Jones matr ix for a planar waveguide structure with a gyrotropic magnetic materia l as one wall. The intensity of the component of the field that is in the polarization state orthogonal to the input was calculated as a fun ction of length of the gyrotropic material and input polarization stat e. The degree of polarization rotation depends on the relative orienta tion of the magnetization in the magnetic material and the direction o f propagation. It is found that there exists an optimal waveguide leng th and input polarization at which the output signal is maximized and that a significant enhancement in polarization rotation is available w ith respect to free-space reflection. These results indicate that a ma gnetic-film-bounded planar waveguide can be used for device applicatio ns such as magnetic field sensors or magneto-optic modulators. (C) 199 8 Optical Society of America OCIS codes: 060.2370, 060.4080, 230.3810, 230.7390, 350.5500.