Experimental realization of optomechanically induced non-reciprocity

Non-magnetic non-reciprocal transparency and amplification is experimentally achieved by optomechanics using a whispering-gallery microresonator. The idea may lead to integrated all-optical isolators or non-reciprocal phase shifters. Non-reciprocal devices, such as circulators and isolators, are indispensable components in classical and quantum information processing in integrated photonic circuits1. Aside from these applications, the non-reciprocal phase shift is of fundamental interest for exploring exotic topological photonics2, such as the realization of chiral edge states and topological protection3,4. However, incorporating low-optical-loss magnetic materials into a photonic chip is technically challenging5. In this study we experimentally demonstrate non-magnetic non-reciprocity using optomechanical interactions in a whispering gallery microresonator, as proposed in a previous work6. Optomechanically induced non-reciprocal transparency and amplification are observed and a non-reciprocal phase shift of up to 40° is also demonstrated. The underlying mechanism of optomechanically induced non-reciprocity has great potential for all-optical controllable isolators and circulators, as well as non-reciprocal phase shifters in integrated photonic chips.