Gallium nitride phononic integrated circuits platform for GHz frequency acoustic wave devices

Abstract

Strong transverse confinement of high-frequency sound and low-loss routing in on-chip waveguides will bring new degrees of freedom to manipulate GHz frequency acoustic waves, analogous to the change brought forth by silicon integrated photonics to the routing and manipulation of light on a chip. Here, we demonstrate that high frequency (>3 GHz) sound can be efficiently guided in μm-scale gallium nitride (GaN) waveguides and ring resonators by exploiting the strong velocity contrast available in the GaN on silicon carbide (SiC) platform. Given the established use of GaN devices in RF amplifiers, our work opens up the possibility of building RF devices with tight integration between the active and passive components on the same die.