Design of a release-free piezo-optomechanical quantum transducer

TL;DR

This paper introduces a novel, release-free piezo-optomechanical transducer that improves thermal anchoring and reduces noise, enabling efficient quantum microwave-optics conversion on a chip.

Contribution

It presents a new release-free transducer design using silicon-on-sapphire and lithium niobate, enhancing thermal and mechanical coherence for quantum transduction.

Findings

Design achieves high mechanical and optomechanical performance.

Integration of SOS and lithium niobate improves thermal anchoring.

Platform is suitable for low-power integrated photonics applications.

Abstract

Quantum transduction between microwave and optical photons could combine the long-range connectivity provided by optical photons with the deterministic quantum operations of superconducting microwave qubits. A promising approach to quantum microwave-optics transduction uses an intermediary mechanical mode along with piezo-optomechanical interactions. So far, such transducers have been released from their underlying substrate to confine mechanical fields -- preventing proper thermal anchoring and creating a noise-efficiency trade-off resulting from optical absorption. Here, we introduce a release-free, i.e. non-suspended, piezo-optomechanical transducer intended to circumvent this noise-efficiency trade-off. We propose and design a silicon-on-sapphire (SOS) release-free transducer with appealing piezo- and optomechanical performance. Our proposal integrates release-free lithium niobate electromechanical crystals with silicon optomechanical crystals on a sapphire substrate meant to improve thermal anchoring along with microwave and mechanical coherence. It leverages high-wavevector mechanical modes firmly guided on the chip surface. Beyond quantum science and engineering, the proposed platform and design principles are attractive for low-power acousto-optic systems in integrated photonics.