Quantum entanglement distribution with 810 nm photons through active telecommunication fibers

TL;DR

This paper demonstrates the distribution of polarization-entangled 810 nm photons through active telecom fibers, enabling quantum key distribution over 6 km with standard network infrastructure.

Contribution

It introduces a practical setup for distributing entangled photons through active telecom fibers carrying classical signals, suitable for real-world quantum networks.

Findings

Successful distribution of entangled photons over 6 km

Compatibility with standard telecom fibers and signals

Quantum key distribution achieved in a real network environment

Abstract

We demonstrate the distribution of polarization-entangled photons for the purpose of quantum key distribution (QKD) along active telecom fibers. Entangled photon pairs of 810 nm wavelength generated by a Sagnac interferometer source were coupled into standard telecom single mode fibers. The fibers were either dark or carrying a standardized 1550 nm ethernet signals (1000BASE-ZX) with a nominal speed of 1 GBps from regular media converter devices, without any requirements on the optical power or spectrum transmitted. Our system demonstrates a QKD network covering 6 km in distance with a central service provider for classical and quantum data.