Quantum-enabled interface between microwave and telecom light (2107.08303v1)

Abstract: Photons at telecom wavelength are the ideal choice for high density interconnects while solid state qubits in the microwave domain offer strong interactions for fast quantum logic. Here we present a general purpose, quantum-enabled interface between itinerant microwave and optical light. We use a pulsed electro-optic transducer at millikelvin temperatures to demonstrate nanosecond timescale control of the converted complex mode amplitude with an input added noise of $N^{oe}_\textrm{in} = 0.16^{+0.02}_{-0.01}$ ($N^{eo}_\textrm{in} = 1.11^{+0.15}_{-0.07}$) quanta for the microwave-to-optics (reverse) direction. Operating with up to unity cooperativity, this work enters the regime of strong coupling cavity quantum electro-optics characterized by unity internal efficiency and nonlinear effects such as the observed laser cooling of a superconducting cavity mode. The high quantum cooperativity of $C_q>10$ forms the basis for deterministic entanglement generation between superconducting circuits and light.