Principles for optimizing quantum transduction in piezo-optomechanical systems

Two-way microwave-optical quantum transduction is essential to connecting distant superconducting qubits via optical fiber and to enable quantum networking at a large scale. In Blésin, Tian, Bhave, and Kippenberg's article [], they lay out a two-way quantum transducer converting between microwave photons and telecom-band photons by way of an intermediary gigahertz-band phonon mode utilizing piezoelectric and optomechanical interactions respectively (and are the first to work out the quantum piezoelectric coupling). In this work, we examine both the piezoelectric, and optomechanical interactions from first principles, and together with the evanescent coupling between optical modes, discuss what parameters matter most in optimizing this kind of quantum transducer. For its additional utility, we have also compiled a table of relevant properties of optical materials that may be used as elements in transducers.