Interaction between guided optical waves and magnetostatic waves in bismuth-doped yttrium-iron-garnet waveguide under inclined magnetic fields

The noncollinear interaction between guided optical waves and magnetostatic waves under inclined bias magnetic field is studied in detail. The diffrac tion efficiency (DE) and the mode-conversion efficiency (MCE) of guided opt ical waves with magnetostatic forward volume waves in the bismuth-doped ytt rium-iron-garnet (Bi-doped YIG) waveguide are calculated numerically. The c alculation results indicate that the DE and the MCE are different in physic al conception and the DE is not equal to the MCE in magnitude under incline d bias magnetic field. The DE may be greatly increased by using an appropri ately inclined bias magnetic field, which has been experimentally confirmed in a pure YIG waveguide. By using an inclined bias magnetic field and the Bi-doped YIG waveguide, under the phase-matching conditions, the maximum DE can come up to 79.5% or more. (C) 1999 American Institute of Physics. [S00 21-8979(99)04518-1].