Collinear interaction of the optical waveguide modes and surface magnetostatic waves in a Lu sub 2. 14 Bi sub 0. 86 Fe sub 4. 94 Mg sub 0. 06 O sub 12 film (SU)

This paper reports the maximum diffraction efficiency per unit microwave power achieved so far in experiments on the interaction of optical waveguide modes with magnetostatic waves (MSW) in ferrimagnetic films. To obtain high efficiency of the interaction a film of Lu{sub 2 .14}Bi{sub 0.86}Fe{sub 4.94}Mg{sub 0.06}O{sub 12} grown on a gadolinium gallium garnet substrate, and collinear propagation of the surface MSW and guided light were used. Measurements of the spectrum of optical modes in the film have shown extremely high values of the birefringence between a TE and a TM mode, induced by the mismatch of the lattice parameters of the film and the substrate ({Delta}{ital n}{sub bi} = 4.5 {times} 10{sup {minus}3}). A He-Ne laser ({lambda}=1.152 {mu}m) was used as the source of optical radiation. The measurements of the efficiency of the interaction were carried out for two geometries: (i) parallel propagation of the light and MSW, and (ii) antiparallel propagation of the light and MSW. As predicted by theory, the efficiency of the parallel interaction was higher than that of the antiparallel interaction. The efficiency for the case of the parallel interaction was of the order of 0.8% per 1 mW of the MSW microwave power.