5 research outputs found
In-field entanglement distribution over a 96 km-long submarine optical fibre
Techniques for the distribution of quantum-secured cryptographic keys have
reached a level of maturity allowing them to be implemented in all kinds of
environments, away from any form of laboratory infrastructure. Here, we detail
the distribution of entanglement between Malta and Sicily over a 96 km-long
submarine telecommunications optical fibre cable. We used this standard
telecommunications fibre as a quantum channel to distribute
polarisation-entangled photons and were able to observe around 257 photon pairs
per second, with a polarisation visibility above 90%. Our experiment
demonstrates the feasibility of using deployed submarine telecommunications
optical fibres as long-distance quantum channels for polarisation-entangled
photons. This opens up a plethora of possibilities for future experiments and
technological applications using existing infrastructure.Comment: 6 pages, 4 figure
Passively stable distribution of polarisation entanglement over 192 km of deployed optical fibre
Quantum key distribution (QKD) based on entangled photon pairs holds the
potential for repeater-based quantum networks connecting clients over long
distance. We demonstrate long-distance entanglement distribution by means of
polarisation-entangled photon pairs through two successive deployed 96 km-long
telecommunications fibres in the same submarine cable. One photon of each pair
was detected directly after the source, while the other travelled the fibre
cable in both directions for a total distance of 192 km and attenuation of 48
dB. The observed two-photon Bell state exhibited a fidelity 85% 2% and
was stable over several hours. We employed neither active stabilisation of the
quantum state nor chromatic dispersion compensation for the fibre.Comment: 7 pages, 3 figure