Perfect Optical Nonreciprocity with Mechanical Driving in a Three-Mode Optomechanical System *

Nonreciprocal devices are indispensable for building quantum networks and ubiquitous in modern communication technology. Here, we study perfect optical nonreciprocity in a three-mode optomechanical system with mechanical driving.The scheme relies on the interference between optomechanical interaction and mechanical driving. We find perfect optical nonreciprocity can be achieved even though nonreciprocal phase difference is zero if we drive the system by a mechanical driving with a nonzero phase. We obtain the essential conditions for perfectoptical nonreciprocity and analyze properties of the optical nonreciprocal transmission. These results can be used to control optical transmission in quantum information processing.