Reduction of the temperature dependence of the nonreciprocal effect of magneto-optic channel waveguides

The nonreciprocal effect is the difference Delta beta= P-forward - beta(bac kward) between forward and backward-propagation constants of optical modes. This effect is analyzed for the fundamental TM00 mode of channel waveguide s in epitaxially grown magnetic garnet films. To increase \Delta beta\, dou ble layers with opposite signs of Faraday rotation are used to prepare the waveguides. It is shown that the temperature dependence of Delta beta can b e reduced considerably if the layer with positive Faraday rotation, which i s at room temperature close to the Curie point, is replaced by a paramagnet ic layer with negligible Faraday rotation. Concurrently, however, \Delta be ta\ is decreased by similar to 35% at 295 K. (C) 1999 Optical Society of Am erica OCIS codes: 130.3130, 160.3820, 230.3240, 230.7380, 230.3810.