Long-distance entanglement-based quantum key distribution over optical fiber.
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-mum 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.
Honjo
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T
NTT Basic Research Laboratories, NTT Corporation, Atsugi-shi 243-0198, Japan. honjo@will.brl.ntt.co.jp
Nam
S W
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Takesue
H
H
Zhang
Q
Q
Kamada
H
H
Nishida
Y
Y
Tadanaga
O
O
Asobe
M
M
Baek
B
B
Hadfield
R
R
Miki
S
S
Fujiwara
M
M
Sasaki
M
M
Wang
Z
Z
Inoue
K
K
Yamamoto
Y
Y
D016494:Computer Security / Q000295:instrumentation*; D017076:Computer-Aided Design; D004867:Equipment Design; D019544:Equipment Failure Analysis; D016247:Information Storage and Retrieval / Q000379:methods*; D055100:Optical Fibers; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D012815:Signal Processing, Computer-Assisted / Q000295:instrumentation*