Realization of Directional Amplification in a Microwave Optomechanical Device

Directional amplification is essential in superconducting quantum information experiments, to measure small signals without disturbing potentially fragile sources. While several classes of amplifiers provide directionality and good noise figures, they generally have low levels of saturation. Optomechanical amplifiers would not suffer from this limitation. This work demonstrates a microwave directional amplifier, based on the directional interference effect between two optomechanical amplifiers. The study reveals this amplifier's robustness to typical nonidealities, and allows the formulation of guidelines for designing multimode optomechanical devices for applied or fundamental physics.