Distributing Polarization Entangled Photon Pairs with High Rate over Long Distance through Standard Telecommunication Fiber

TL;DR

This paper demonstrates high-rate distribution of polarization-entangled photon pairs over 50 km of standard telecommunication fiber, enabling practical quantum communication with existing infrastructure.

Contribution

It introduces a bright non-degenerate photon pair source optimized for low dispersion and high detection efficiency, achieving over 10,000 pairs per second over long distances.

Findings

Entanglement distribution achieved over 50 km fiber

Photon pair rate exceeds 10,000 s$^{-1}$

Optimized wavelengths for low dispersion and high detection efficiency

Abstract

Entanglement distribution over long distances is essential for many quantum communication schemes like quantum teleportation, some variants of quantum key distribution, or implementations of a quantum internet. Distributing entanglement through standard telecommunication fiber is particularly important for quantum key distribution protocols with low vulnerability over metropolitan distances. However, entanglement distribution over long distance through optical fiber so far could only be accomplished with moderate photon pair rates. In this work, we present entanglement distribution over 50km of standard telecommunication fiber with pair rate more than 10,000 s$^{-1}$ using a bright non-degenerate photon pair source. Signal and idler wavelengths of this source are optimized for low dispersion in optical fiber and high efficiency for single-photon avalanche diode detectors, respectively. The resulting modest hardware requirement and high rate of detected entangled photon pairs could significantly enhance practical entanglement-based quantum key distribution in existing metropolitan fiber networks.