Quantum Squeezing Induced Optical Nonreciprocity

TL;DR

This paper introduces a novel all-optical nonreciprocal device using quantum squeezing in coupled resonators, enabling chip-scale optical isolation and quantum information processing with high fidelity and low loss.

Contribution

It presents a new method to achieve optical nonreciprocity through quantum squeezing and chiral photon interactions in integrated resonator systems.

Findings

Achieves >40 dB isolation ratio in optical diode.

Fidelity >98% for the quasi-circulator.

Insertion loss <1 dB for both devices.

Abstract

We propose an all-optical approach to achieve optical nonreciprocity on a chip by quantum squeezing one of two coupled resonator modes. By parametric pumping a nonlinear resonator unidirectionally with a classical coherent field, we squeeze the resonator mode in a selective direction due to the phase-matching condition, and induce a chiral photon interaction between two resonators. Based on this chiral interresonator coupling, we achieve an all-optical diode and a three-port quasi-circulator. By applying a second squeezed-vacuum field to the squeezed resonator mode, our nonreciprocal device also works for single-photon pulses. We obtain an isolation ratio of >40 dB for the diode and fidelity of $>98\%$ for the quasi-circulator, and insertion loss of <1 dB for both. We also show that nonreciprocal transmission of strong light can be switched on and off by a relative weak pump light. This achievement implies a nonreciprocal optical transistor. Our protocol opens up a new route to achieve integrable all-optical nonreciprocal devices permitting chip-compatible optical isolation and nonreciporcal quantum information processing.