Long-distance quantum key distribution in optical fibre
Philip A. Hiskett, D. Rosenberg, Charles G. Peterson, Richard Hughes, Sae Woo Nam, Adriana E. Lita, Aaron Miller, J. E. Nordholt · New Journal of Physics · 2006
Use of low-noise detectors can both increase the secret bit rate of long-distance quantum key distribution (QKD) and dramatically extend the length of a fibre optic link over which secure keys can be distributed. Previous work has demonstrated the use of ultra-low-noise transition-edge sensors (TESs) in a QKD system with transmission over 50 km. In this study, we demonstrate the potential of the TESs by successfully generating an error-corrected, privacy-amplified key over 148.7 km of dark optical fibre at a mean photon number μ = 0.1, or 184.6 km of dark optical fibre at a mean photon number of 0.5. We have also exchanged secret keys over 67.5 km that is secure against powerful photon-number-splitting (PNS) attacks.