Certifying position-momentum entanglement at telecommunication wavelengths

TL;DR

This paper demonstrates the first experimental certification of position-momentum EPR entanglement of photon pairs at telecommunication wavelengths, showing high-dimensional quantum correlations compatible with existing telecom infrastructure.

Contribution

It reports the first certification of position-momentum EPR entanglement at telecom wavelengths using SPDC, advancing integration into quantum communication networks.

Findings

EPR correlations certified with up to 45 standard deviations

Entanglement of formation exceeds one, indicating high-dimensional entanglement

Source operates at 1550 nm, compatible with current telecom infrastructure

Abstract

TheThe successful employment of high-dimensional quantum correlations and its integration in telecommunication infrastructures is vital in cutting-edge quantum technologies for increasing robustness and key generation rate. Position-momentum Einstein-Podolsky-Rosen (EPR) entanglement of photon pairs are a promising resource of such high-dimensional quantum correlations. Here, we experimentally certify EPR correlations of photon pairs generated by spontaneous parametric down-conversion (SPDC) in a nonlinear crystal with type-0 phase-matching at telecommunication wavelength for the first time. To experimentally observe EPR entanglement, we perform scanning measurements in the near- and far-field planes of the signal and idler modes. We certify EPR correlations with high statistical significance of up to 45 standard deviations. Furthermore, we determine the entanglement of formation of our source to be greater than one, indicating a dimensionality of greater than 2. Operating at telecommunication wavelengths around 1550 nm, our source is compatible with today's deployed telecommunication infrastructure, thus paving the way for integrating sources of high-dimensional entanglement into quantum-communication infrastructures.