Transmission Nonreciprocity in a Mutually Coupled Circulating Structure
arXiv:1908.03280 · doi:10.1103/PhysRevLett.120.203904
The paper proposes a three‑cavity (or fiber‑ring) structure that achieves nonreciprocal light transmission using linear optics, either through gain saturation or asymmetric coupling, without violating Lorentz reciprocity.
Abstract
Breaking Lorentz reciprocity was believed to be a prerequisite for nonreciprocal transmissions of light fields, so the possibility of nonreciprocity by linear optical systems was mostly ignored. We put forward a structure of three mutually coupled microcavities or optical fiber rings to realize optical nonreciprocity. Although its couplings with the fields from two different input ports are constantly equal, such system transmits them nonreciprocally either under the saturation of an optical gain in one of the cavities or with the asymmetric couplings of the circulating fields in different cavities. The structure made up of optical fiber rings can perform nonreciprocal transmissions as a time-independent linear system without breaking Lorentz reciprocity. Optical isolation for inputs simultaneously from two different ports and even approximate optical isolator operations are implementable with the structure.
6 pages and 4 figures. The resolutions of the figure files are lowered, and the supplementary materials are not included, due to the upload limit imposed by ArXiv