Quantum teleportation across a metropolitan fibre network

TL;DR

This paper demonstrates quantum teleportation over a 6.2 km metropolitan fibre network using telecommunication wavelengths, advancing the distance for practical quantum communication and supporting future quantum internet development.

Contribution

It reports the first teleportation of a telecommunication-wavelength photon over several kilometres, a significant improvement over previous distances, using a real fibre network.

Findings

Teleportation distance increased from 818 m to 6.2 km.

Successful teleportation of telecommunication-wavelength photons.

Supports development of quantum repeaters and global quantum internet.

Abstract

If a photon interacts with a member of an entangled photon pair via a so-called Bell-state measurement (BSM), its state is teleported over principally arbitrary distances onto the second member of the pair. Starting in 1997, this puzzling prediction of quantum mechanics has been demonstrated many times; however, with one very recent exception, only the photon that received the teleported state, if any, travelled far while the photons partaking in the BSM were always measured closely to where they were created. Here, using the Calgary fibre network, we report quantum teleportation from a telecommunication-wavelength photon, interacting with another telecommunication photon after both have travelled over several kilometres in bee-line, onto a photon at 795~nm wavelength. This improves the distance over which teleportation takes place from 818~m to 6.2~km. Our demonstration establishes an important requirement for quantum repeater-based communications and constitutes a milestone on the path to a global quantum Internet.