Two-photon interference from a bright single photon source at telecom wavelengths

TL;DR

This paper demonstrates a bright, deterministic single-photon source at telecom wavelengths using a quantum dot in a nanophotonic cavity, achieving high purity and partial indistinguishability for quantum communication.

Contribution

It introduces a cavity-enhanced quantum dot source capable of producing high-purity, indistinguishable photons at telecom wavelengths with significant emission rate improvements.

Findings

High out-coupling efficiency exceeding 36%

Purcell enhancement of spontaneous emission up to 4

Two-photon interference visibility of 67% with post-selection

Abstract

Long-distance quantum communication relies on the ability to efficiently generate and prepare single photons at telecom wavelengths. In many applications these photons must also be indistinguishable such that they exhibit interference on a beamsplitter, which implements effective photon-photon interactions. However, deterministic generation of indistinguishable single photons with high brightness remains a challenging problem. We demonstrate two-photon interference at telecom wavelengths using an InAs/InP quantum dot in a nanophotonic cavity. The cavity enhances the quantum dot emission, resulting in a nearly Gaussian transverse mode profile with high out-coupling efficiency exceeding 36% after multi-photon correction. We also observe Purcell enhanced spontaneous emission rate up to 4. Using this source, we generate linearly polarized, high purity single photons at 1.3 micron wavelength and demonstrate the indistinguishable nature of the emission using a two-photon interference measurement, which exhibits indistinguishable visibilities of 18% without post-selection and 67% with post-selection. Our results provide a promising approach to generate bright, deterministic single photons at telecom wavelength for applications in quantum networking and quantum communication.