Quantum entanglement distribution with 810 nm photons through telecom fibers

TL;DR

This paper demonstrates the distribution of polarization-entangled 810 nm photons through standard telecom fibers, enabling quantum communication with high-quality entanglement over several kilometers using existing infrastructure.

Contribution

It introduces a method for distributing entangled photons at 810 nm through telecom fibers, leveraging better-performing setups at this wavelength compared to traditional telecom wavelengths.

Findings

Achieved 95.6% entanglement visibility.

Distributed entanglement over 6 km fiber.

Performed quantum key distribution over 4.4 km fiber.

Abstract

We demonstrate the distribution of polarization entangled photons of wavelength 810 nm through standard telecom fibers. This technique allows quantum communication protocols to be performed over established fiber infrastructure, and makes use of the smaller and better performing setups available around 800 nm, as compared to those which use telecom wavelengths around 1550 nm. We examine the excitation and subsequent quenching of higher-order spatial modes in telecom fibers up to 6 km in length, and perform a distribution of high quality entanglement (visibility 95.6%). Finally, we demonstrate quantum key distribution using entangled 810 nm photons over a 4.4 km long installed telecom fiber link.