On-chip low loss heralded source of pure single photons

TL;DR

This paper presents a low-loss, on-chip heralded single-photon source in silica photonics, achieving high purity and efficiency, advancing quantum photonic technologies.

Contribution

Demonstrates a silica photonic chip generating heralded single photons with high purity and efficiency without filtering, suitable for quantum optics applications.

Findings

Heralding efficiency of 40% achieved

Single photon purity of 0.86 measured

Potential for high-purity output across spectral regions

Abstract

A key obstacle to the experimental realization of many photonic quantum-enhanced technologies is the lack of low-loss sources of single photons in pure quantum states. We demonstrate a promising solution: generation of heralded single photons in a silica photonic chip by spontaneous four-wave mixing. A heralding efficiency of 40%, corresponding to a preparation efficiency of 80% accounting for detector performance, is achieved due to efficient coupling of the low-loss source to optical fibers. A single photon purity of 0.86 is measured from the source number statistics without filtering, and confirmed by direct measurement of the joint spectral intensity. We calculate that similar high-heralded-purity output can be obtained from visible to telecom spectral regions using this approach. On-chip silica sources can have immediate application in a wide range of single-photon quantum optics applications which employ silica photonics.