Microwave-to-optics conversion in the quantum ground state

Microwave-to-optical quantum converters represent an indispensable component for quantum communication in future quantum networks. To maintain quantum coherence, it is critical for such devices to operate at milli-Kelvin temperatures in the quantum ground state. Integrating photonics with superconductors at milli-Kelvin temperatures is particularly challenging since the optical excitation leads to excess microwave noise, thus placing the device systems in a thermal state as opposed to the desired ground state. In this work, I will present our experimental progress in demonstrating efficient bidirectional microwave-to-optical conversion with an electro-optic device fabricated on an integrated photonic platform in a milli-Kelvin environment. Our device operates near its quantum ground state and meanwhile offers high conversion efficiency that is suitable for building a two-node quantum network through heralding protocols.