Integrated AlGaAs source of highly indistinguishable and energy-time entangled photons

TL;DR

This paper presents a chip-based AlGaAs source capable of generating highly indistinguishable and energy-time entangled photon pairs at telecom wavelengths, advancing integrated quantum photonics.

Contribution

It introduces a novel AlGaAs chip source that produces bright, indistinguishable, and energy-time entangled photons with high fidelity and practical brightness.

Findings

Brightness of $7.2\times10^6$ pairs/s

Hong-Ou-Mandel visibility of $89\pm3\%$

Bell parameter $S=2.70\pm0.10$

Abstract

The generation of nonclassical states of light in miniature chips is a crucial step towards practical implementations of future quantum technologies. Semiconductor materials are ideal to achieve extremely compact and massively parallel systems and several platforms are currently under development. In this context, spontaneous parametric down conversion in AlGaAs devices combines the advantages of room temperature operation, possibility of electrical injection and emission in the telecom band. Here we report on a chip-based AlGaAs source, producing indistinguishable and energy-time entangled photons with a brightness of $7.2\times10^6$ pairs/s and a signal-to-noise ratio of $141\pm12$. Indistinguishability between the photons is demonstrated via a Hong-Ou-Mandel experiment with a visibility of $89\pm3\%$, while energy-time entanglement is tested via a Franson interferometer leading to a value for the Bell parameter $ S=2.70\pm0.10$.