Quantum-enabled microwave-to-optical transduction via silicon nanomechanics

An interface between microwave and optical photons offers the potential to network remote superconducting quantum processors. To preserve fragile quantum states, a microwave-to-optical transducer must operate efficiently in the quantum-enabled regime by generating less than one photon of noise referred to its input. Here we achieve these criteria using an integrated electro-optomechanical device made from crystalline silicon. Our platform eliminates the need for heterogeneous integration with piezoelectric materials by utilizing electrostatic actuation of gigahertz-frequency nanomechanical oscillators. Leveraging the ultra-low mechanical dissipation in silicon, our microwave-to-optical transducers achieve below one photon of input-referred added noise (n_add = 0.58) under continuous-wave laser drives. This demonstration of continuous quantum-enabled microwave-to-optical transduction improves the upconversion rate by about two orders of magnitude beyond the state of the art (R = 0.47-1.9 kHz). The increased transduction rate and scalable fabrication of our devices may facilitate near-term use of transducers in distributed quantum computers and quantum networks.