Entanglement swapping between independent and asynchronous integrated photon-pair sources

TL;DR

This paper demonstrates high-visibility entanglement swapping between two independent integrated silicon nitride photon-pair sources, showcasing their potential for scalable quantum communication networks.

Contribution

It presents the first implementation of entanglement swapping using two independent integrated silicon nitride microring resonator sources with high spectral purity and interference visibility.

Findings

Spectral purity up to 0.97 achieved

HOM interference visibility of 93.2% observed

Entanglement swapping visibility reached 91.2%

Abstract

Integrated photonics represents a technology that could greatly improve quantum communication networks in terms of cost, size, scaling, and robustness. A key benchmark for this is to demonstrate their performance in complex quantum networking protocols, such as entanglement swapping between independent photon-pair sources. Here, using time-resolved detection, and two independent and integrated Si$_3$N$_4$ microring resonator photon-pair sources, operating in the CW regime at telecom wavelengths, we obtained spectral purities up to $0.97 \pm 0.02$ and a HOM interference visibility between the two sources of $V_{\rm HOM}=93.2 \pm 1.6\,\%$. This results in entanglement swapping visibility as high as $91.2 \pm 3.4\,\%$