Piezo-Optomechanical Signal Transduction Using Lamb-Wave Supermodes in a Suspended GalliumArsenide Photonic-Integrated-Circuit Platform

Piezoelectric optomechanical platforms present one of the most promising routes towards efficient transduction of signals from the microwave to the optical frequency domains. While there has been significant recent progress particularly on the materials front, alternative device architectures that can potentially meet the stringent efficiency requirements of quantum transducers need to be continuously explored. In. this work, we utilize the mechanical supermode principle to improve the overall microwave-to-optical transduction efficiency, by fabricating Lamb-wave resonators that are hybridized with the mechanical breathing modes of a rib waveguide in a suspended gallium arsenide (GaAs) photonic-integrated-circuit platform. Combining the strong elasto-optic interactions available in GaAs with the increased phonon injection efficiency enabled by this architecture, we demonstrate signal transduction up to 7 GHz, and an increase in transduction efficiency of approximately 25 times for the hybridized mode (f_m ≈ 2 GHz), using this approach. We also outline routes for improving device performance to enable quantum transduction within this platform.