Bell states generation on a III-V semiconductor chip at room temperature

TL;DR

This paper reports the successful generation of polarization-entangled photon pairs at room temperature using an AlGaAs semiconductor waveguide, advancing integrated quantum photonics with high fidelity and potential for electrical injection.

Contribution

It introduces a novel room-temperature, telecom-wavelength entangled photon source on a III-V semiconductor chip with high fidelity and compatibility with electrical injection.

Findings

Raw fidelity to Bell state of 0.83

Theoretical model explains entanglement control

Compatibility with electrical injection demonstrated

Abstract

We demonstrate the generation of polarization-entangled photon pairs at room temperature and telecom wavelength in a AlGaAs semiconductor waveguide. The source is based on spontaneous parametric down conversion with a counterpropagating phase-matching scheme. The quality of the two-photon state is assessed by the reconstruction of the density matrix giving a raw fidelity to a Bell state of 0.83; a theoretical model, taking into account the experimental parameters, provides ways to understand and control the amount of entanglement. Its compatibility with electrical injection, together with the high versatility of the generated two-photon state, make this source an attractive candidate for completely integrated quantum photonics devices.