FORWARD VOLUME WAVE MICROWAVE ENVELOPE SOLITONS IN YTTRIUM-IRON-GARNET FILMS - PROPAGATION, DECAY, AND COLLISION

Magnetostatic forward volume wave (FVW) microwave magnetic envelope solitons in 7.2 mum thick, single-crystal yttrium iron garnet films have been studied at 5.6-6.0 GHz. Rectangular input pulses with peak powers up to 3 W and pulse widths 5-50 ns were used. Single soliton output pulses with a characteristic increase in amplitude and pulse narrowing are observed when the power or width of the rectangular input microwave pulse exceeds threshold levels. Above these levels, output pulse peak power versus input power or pulse width exhibits a nonlinear increase and shows saturation effects. Multiple peak output profiles are observed for pulse powers and widths well above threshold. Solitons could be formed for all frequencies within the usable, low transmission loss portion of the magnetostatic FVW band. The use of reflected pulses from the film edge made it possible to study soliton decay and soliton collisions. The soliton decay rate was found to be approximately twice the linear rate, as expected from theory. The collision of solitons was found to occur with no significant change in shape and velocity. The various characteristic times from theory for pulse decay, pulse dispersion, nonlinear response, and propagation are found to be consistent with the experimental results.