Nonlinear Surface Acoustic Wave Grating for Parametric Amplification

In this paper we explore parametric amplification on the acoustic wave platform for the purpose of developing nonlinear devices such as amplifiers and mixers. The advantage of acoustic wave platform over conventional electromagnetic platform is that the former obtains great leverage on short wavelength and low loss of acoustic wave at radio frequency to achieve devices with small footprints and high quality factor. To realize efficient parametric amplification a nonlinear surface acoustic wave (SAW) grating is employed to couple acoustic waves through different frequencies. Novel implementation of nonlinear SAW grating by coupling nonlinear permittivity of Barium Strontium Titanite (BST) to mechanical stiffness of Lithium Niobate has been proved by both theory and simulation. Parametric gain is realized with optimal grating length and tunable permittivity of commercial BST thin film.