Electromechanical cooperativity greater than 1,000 in an electro-opto-mechanical transducer

Realizing a network of superconducting quantum computational nodes connected over long distances by optical fibers will require a highly efficient and low-noise microwave-to-optical transducer. A mechanical mode of a Si3N4 membrane simultaneously coupled to a superconducting LC circuit and a high finesse optical Fabry-Perot cavity can mediate transduction between the electromagnetic modes with the help of strong parametric pumps. Our implementation of such a transducer has achieved 47% efficiency and only 3.2 photons of input-referred added noise in up-conversion [1]. Surpassing the quantum threshold of 1 photon of added noise can be achieved by optimization of the microwave cavity loss rate, the technical noise induced by the microwave pump, and the electromechanical coupling rate. Here, we present progress on these optimizations with the goal of ground-state cooling the mechanical mode with the electromechanical interaction, a necessary requirement for quantum-enabled microwave-to-optical transduction.

[1] Brubaker, B. M., Kindem, J. M., Urmey, M.D, et. al., Optomechanical Ground-State Cooling in a Continuous and Efficient Electro-Optic Transducer, Phys. Rev. X 12, 021062