Experimental Demonstration of Free-Space Decoy-State Quantum Key Distribution over 144 km

Author(s): T. Schmitt-Manderbach, A. Zeilinger, J. G. Rarity, C. Kurtsiefer, Z. Sodnik, J. Perdigues, T. Scheidl, F. Tiefenbacher, R. Ursin, M. Fuerst, H. Weier, H. Weinfurter

Journal: Physical Review Letters

Volume: 98

Page(s): 010504

Year: 2007

DOI Number: --

Link: Link to publication


We report on the experimental implementation of a Bennett-Brassard 1984 (BB84) protocol type quantum key distribution over a 144 km free-space link using weak coherent laser pulses. Optimization of the link transmission was achieved with bidirectional active telescope tracking, and the security was ensured by employing decoy-state analysis. This enabled us to distribute a secure key at a rate of 12:8 bit=s at an attenuation of about 35 dB. Utilizing a simple transmitter setup and an optical ground station capable of tracking a spacecraft in low earth orbit, this outdoor experiment demonstrates the feasibility of global key distribution via satellites.

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