Nonlinear phase shifters based on forward volume spin waves

A microwave nonlinear phase shifter based on forward volume spin waves (FVSWs) is studied. The device is fabricated with perpendicularly magnetized 5.2-mu m thick single-crystal yttrium iron garnet film. The performance characteristics of the device are measured for the bias magnetic field of 1850-3700 Oe. The obtained results show that the nonlinear phase shifter produces a power-dependent phase shift of a microwave signal. The nonlinear phase shift (NLPS) appears with the signal power increasing and demonstrates almost linear rise up to 180 degrees. With constant incident microwave power, the NLPS is a decreasing function of the bias magnetic field. A nonlinear damping of the FVSWs restricts the linear rise of the device output power with incident power increasing. The experimental data are in good agreement with theory. The phenomenological parameters describing the FVSWs nonlinear damping are determined. (C) 2013 American Institute of Physics. [http://dx.doi.org/10.1063/1.4795165]