Noncollinear interaction of guided optical waves and magnetostatic forwardvolume waves under inclined bias magnetic field

Coupled-mode equations for Stokes and anti-Stokes interactions of guided op tical waves with magnetostatic forward volume waves under inclined magnetic field are given. Calculation results indicate that, only at normal magneti zation, the diffraction efficiency (DE) is equal to the mode-conversion eff iciency (MCE) in magnitude; by comparison to the case of normal magnetizati on, the DE and the MCE can be increased greatly under appropriate inclined magnetic field. For the YIG waveguide used, the DE for the Stokes interacti on is much greater than that for the anti-Stokes interaction when the incli ned angle \theta\ < 25 degrees and the MCE is symmetrical about theta. For the Bi-doped YIG film, the MCE presents a rapid oscillation with theta. The obtained results tally with the experiments.