Long-distance entanglement-based quantum key distribution over optical fiber

T. Honjo, S. W. Nam, H. Takesue, Q. Zhang, H. Kamada, Y. Nishida, O. Tadanaga, M. Asobe, B. Baek, R. Hadfield, S. Miki, M. Fujiwara, M. Sasaki, Z. Wang, K. Inoue, Y. Yamamoto

Research output: Contribution to journalArticlepeer-review

86 Citations (Scopus)


We report the first entanglement-based quantum key distribution (QKD) experiment over a 100-km optical fiber. We used superconducting single photon detectors based on NbN nanowires that provide high-speed single photon detection for the 1.5-mu m telecom band, an efficient entangled photon pair source that consists of a fiber coupled periodically poled lithium niobate waveguide and ultra low loss filters, and planar lightwave circuit Mach-Zehnder interferometers (MZIs) with ultra stable operation. These characteristics enabled us to perform an entanglement-based QKD experiment over a 100-km optical fiber. In the experiment, which lasted approximately 8 hours, we successfully generated a 16 kbit sifted key with a quantum bit error rate of 6.9% at a rate of 0.59 bits per second, from which we were able to distill a 3.9 kbit secure key. (C) 2008 Optical Society of America

Original languageEnglish
Pages (from-to)19118-19126
Number of pages9
JournalOptics Express
Issue number23
Publication statusPublished - 10 Nov 2008


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