MICROWAVE AND MAGNETOOPTIC MEASUREMENTS OF NONLINEAR DISPERSIVE MAGNETOSTATIC WAVES IN A YTTRIUM-IRON-GARNET-GADOLINIUM-GALLIUM-GARNET WAVE-GUIDE

Nonlinear propagation characteristics of magnetostatic surface waves ( MSSWs) with carrier frequencies ranging from 0.5 to 7.0 GHz and magnet ostatic forward volume waves (MSFVWs) with carrier frequencies ranging from 0.5 to 5.0 GHz in yttrium iron garnet-gadolinium gallium garnet waveguides have been measured in a delay line configuration using both microwave and guided-wave magnetooptic (MO) methods. The latter, invo lving noncollinear guided-wave MO Bragg interaction, was employed for the first time. For the MSSW, nonlinear characteristics including powe r limiting, discrete sideband modulation, continuum sideband modulatio n, and group splitting were observed and measured. Among such nonlinea r characteristics, continuum modulation spectrum was observed and meas ured for the first time. For the MSFVW, nonlinear characteristics incl uding parametric instability and soliton formation were also observed and measured. The MO data obtained by scanning the location of the inc ident light beam right beneath the input transducer and along the MSW propagation path has shown that the nonlinear characteristics observed were related to propagation and not to electromagnetic to MSW convers ion effects at the input. Theoretical estimates are in a fair agreemen t with the experimental data, Finally, compression of an input pulse o f 60 rf cycles (20 ns in width) to an output pulse of 6 rf cycles (2 n s in width) using a 3 GHz MSFVW pulse was also demonstrated. (C) 1998 American Institute of Physics.