Inherent polarization entanglement generated from a monolithic semiconductor chip

TL;DR

This paper demonstrates a monolithic gallium arsenide chip that directly generates polarization-entangled photon pairs via spontaneous parametric down conversion, promising scalable and stable quantum photonic devices.

Contribution

It introduces a monolithic BRW architecture capable of producing polarization-entangled photons without additional filtering or compensation, advancing integrated quantum photonics.

Findings

Successful generation of polarization-entangled photons on-chip

Non-classical polarization correlations confirmed

Potential for scalable quantum information processing

Abstract

Creating miniature chip scale implementations of optical quantum information protocols is a dream for many in the quantum optics community. This is largely because of the promise of stability and scalability. Here we present a monolithically integratable chip architecture upon which is built a photonic device primitive called a Bragg reflection waveguide (BRW). Implemented in gallium arsenide, we show that, via the process of spontaneous parametric down conversion, the BRW is capable of directly producing polarization entangled photons without additional path difference compensation, spectral filtering or post-selection. After splitting the twin-photons immediately after they emerge from the chip, we perform a variety of correlation tests on the photon pairs and show non-classical behaviour in their polarization. Combined with the BRW's versatile architecture our results signify the BRW design as a serious contender on which to build large scale implementations of optical quantum processing devices.