arXiv:quant-ph/0501175 · Physical Review A

Security improvement by using a modified coherent state for quantum cryptography

Y. J. Lu, Luobei Zhu, Z. Y. Ou

Published Mar 16, 2005• 21 citations

Abstract

Weak coherent states as a photon source for quantum cryptography have a limit in secure data rate and transmission distance because of the presence of multiphoton events and loss in transmission line. Two-photon events in a coherent state can be taken out by a two-photon interference scheme. We investigate the security issue of utilizing this modified coherent state in quantum cryptography. A 4-dB improvement in the secure data rate or a nearly twofold increase in transmission distance over the coherent state are found. With a recently proposed and improved encoding strategy, further improvement is possible.

DOI: 10.1103/physreva.71.032315

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