Microresonator Isolators and Circulators Based on the Intrinsic Nonreciprocity of the Kerr Effect

TL;DR

This paper demonstrates how intrinsic Kerr nonlinearity in microresonators can be exploited to create optical isolators and circulators with high isolation, advancing integrated photonics without requiring magnetic materials.

Contribution

It introduces a novel approach using Kerr effect-induced nonreciprocity in microresonators to realize optical isolators and circulators, with experimental validation and theoretical modeling.

Findings

Over 24 dB optical isolation achieved

Theoretical model for power scaling of nonreciprocity

Potential for integration into photonic circuits

Abstract

Nonreciprocal light propagation is important in many applications, ranging from optical telecommunications to integrated photonics. A simple way to achieve optical nonreciprocity is to use the nonlinear interaction between counterpropagating light in a Kerr medium. Within a ring resonator, this leads to spontaneous symmetry breaking, with the result that light of a given frequency can circulate in one direction, but not in both directions simultaneously. In this work, we demonstrate that this effect can be used to realize optical isolators and circulators based on a single ultra- high-Q microresonator. We obtain isolation of more than 24 dB and develop a theoretical model for the power scaling of the attainable nonreciprocity.