2-GHz clock quantum key distribution over 260 km of standard telecom fiber

[Eugen Leitl]

http://arxiv.org/abs/1203.4323

2-GHz clock quantum key distribution over 260 km of standard telecom fiber

Shuang Wang, Wei Chen, Jun-Fu Guo, Zhen-Qiang Yin, Hong-Wei Li, Zheng Zhou,
Guang-Can Guo, Zheng-Fu Han

(Submitted on 20 Mar 2012)

    We report a demonstration of quantum key distribution (QKD) over a
standard telecom fiber exceeding 50 dB in loss and 250 km in length. The
differential phase shift QKD protocol was chosen and implemented with 2 GHz
system clock rate. By careful optimization of the 1-bit delayed
Faraday-Michelson interferometer and the use of the super-conducting single
photon detector (SSPD), we achieved a quantum bit error rate below 2% when
the fiber length was no more than 205 km, and of 3.45% for the 260 km length
fiber with 52.9 dB loss. We also improved the quantum efficiency of SSPD to
obtain high key rate for 50 km length. 

Subjects: 	Quantum Physics (quant-ph)

Journal reference: 	Optics Letters, 37, 1008-1010 (2012)

DOI: 	10.1364/OL.37.001008

Cite as: 	arXiv:1203.4323v1 [quant-ph]