WIDE-BAND OPTICAL MODULATION VIA THE MAGNETOOPTIC INTERACTION IN A BISMUTH-LUTETIUM-IRON GARNET FILM

Optical modulation with a bandwidth of about 3 GHz centered at 5.75 GH z was observed in a thin film of [BiLu](3)Fe5O12 using the magneto-opt ical interaction, A microstrip transducer was placed in contact with t he film and TM polarized optical guided modes were excited beneath and parallel to the transducer. The TM-->TE mode conversion was measured as a function of the angle between an in-plane field, of up to 100 Oe, and the optical beam, The bandwidth of the modulation was limited by the microwave components used in the external circuit, The experiments qualitatively agree with a simple model that describes a modulation o f the optical beam by a nonresonant precession of the magnetization ab out an equilibrium. (C) 1997 American Institute of Physics.