Feasibility of 300 km quantum key distribution with entangled states

Autor(en)

Thomas Scheidl, Rupert Ursin, Alessandro Fedrizzi, Sven Ramelow, Xiaosong Ma, Thomas Herbst, Robert Prevedel, Lothar Ratschbacher, Johannes Kofler, Thomas Jennewein, Anton Zeilinger

Abstrakt

A significant limitation of practical quantum key distribution (QKD) setups is currently their limited operational range. It has recently been emphasized (Ma et al 2007 Phys. Rev. A 76 012307) that entanglement-based QKD systems can tolerate higher channel losses than systems based on weak coherent laser pulses (WCP), in particular, when the source is located symmetrically between the two communicating parties, Alice and Bob. In the work presented here, we experimentally study this important advantage by implementing different entanglement-based QKD setups on a 144 km free-space link between the two Canary Islands of La Palma and Tenerife. We established three different configurations where the entangled photon source was placed at Alice's location, asymmetrically between Alice and Bob and symmetrically in the middle between Alice and Bob, respectively. The resulting quantum channel attenuations of 35, 58 and 71 dB, respectively, significantly exceed the limit for WCP systems (Ma et al 2007 Phys. Rev. A 76 012307). This confirms that QKD over distances of 300 km and even more is feasible with entangled state sources placed in the middle between Alice and Bob.

Organisation(en)

Quantenoptik, Quantennanophysik und Quanteninformation

Externe Organisation(en)

Österreichische Akademie der Wissenschaften (ÖAW)

Journal

New Journal of Physics

Band

11

Anzahl der Seiten

13

ISSN

1367-2630

DOI

https://doi.org/10.1088/1367-2630/11/8/085002

Publikationsdatum

2009

Peer-reviewed

Ja

ÖFOS 2012

103026 Quantenoptik

Link zum Portal

https://ucrisportal.univie.ac.at/de/publications/5556a61c-201b-4bb3-b1e0-a262a2af4278