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Quantum key distribution over 122 km of standard telecom fiber

C. Gobby·Z. L. Yuan·A. J. Shields
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Abstract

We report the first demonstration of quantum key distribution over a standard telecom fiber exceeding 100 km in length. Through careful optimisation of the interferometer and single photon detector, we achieve a quantum bit error ratio of 8.9% for a 122km link, allowing a secure shared key to be formed after error correction and privacy amplification. Key formation rates of up to 1.9 kbit/sec are achieved depending upon fiber length. We discuss the factors limiting the maximum fiber length in quantum cryptography.

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C. Gobby, Z. L. Yuan, A. J. Shields. 2004-12-22. Quantum key distribution over 122 km of standard telecom fiber. https://doi.org/10.1063/1.1738173

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