A quantum optical valve in a nonlinear-linear resonator junction

TL;DR

This paper introduces a quantum optical valve based on a nonlinear-linear resonator junction that can function as a diode, rectified source, or splitter, advancing non-reciprocal photonic devices for quantum applications.

Contribution

It proposes a simple, versatile quantum device structure capable of multiple rectification functions, including diode, photon source, and splitter, relevant for quantum photonic circuits.

Findings

The nonlinear-linear junction acts as a versatile quantum optical valve.

It can be tuned to operate as a photonic diode or rectified source.

The device enables non-reciprocal operations in integrated quantum photonics.

Abstract

Electronic diodes, which enable the rectification of an electrical energy flux, have played a crucial role in the development of current microelectronics after the invention of semiconductor p-n junctions. Analogously, signal rectification at specific target wavelengths has recently become a key goal in optical communication and signal processing. Here we propose a genuinely quantum device with the essential rectifying features being demonstrated in a general model of a nonlinear-linear junction of coupled resonators. It is shown that such a surprisingly simple structure is a versatile valve and may be alternatively tuned to behave as: a photonic diode, a single or two-photon rectified source turning a classical input into a quantum output depending on the input frequency, or a quantum photonic splitter. Given the relevance of non-reciprocal operations in integrated circuits, the nonlinear-linear junction realises a crucial building component in prospective quantum photonic applications.