Amplification of Microwave Magnetic Envelope Solitons in Thin Yttrium Iron Garnet Films by Parallel Pumping

The parametric amplification of 4.01 GHz, 22 ns wide microwave magnetic envelope (MME) backward volume wave pulses by parallel pumping has been realized in yttrium iron garnet (YIG) films. The parametric parallel pumping was achieved with 15--23 ns wide pulses applied to a strip line resonator at a frequency ωₚ approximately twice the signal frequency ωₛ. Low power linear MME pulse signals were pumped to form solitons with a gain of 20 dB, and soliton signals could be boosted by 8 dB. These large gain factors occur only when ωₚ is upshifted from 2ωₛ by 30 MHz. This upshift is critical and is related to the nonlinear nature of the soliton signal.