A nonreciprocal reconfigurable microwave optomechanical circuit: isolation, circulation and directional amplification*

Nonreciprocal devices such as isolators or circulators are ubiquitous in a wide range of communication systems and are particularly indispensable in the readout chains of superconducting quantum circuits. Typically, the operation of these devices relies on ferrite materials. Here we realise reconfigurable nonreciprocal transmission between two microwave modes using purely optomechanical interactions in a superconducting electromechanical circuit. We analyse the transmission as well as the noise properties of this system. The scheme relies on the interference in two mechanical modes that mediate coupling between microwave cavities. We show how quantum-limited circulators can be realized with the same principle and discuss the progress towards all-optomechanically mediated directional amplifiers. The technology can be built on-chip without any external magnetic field, rendering it compatible with superconducting quantum circuits. The results also highlight the potential of utilising dissipation in multimode optomechanical systems.