The length of a secure link over which a quantum key can be distributed depends on the efficiency and dark-count rate of the detectors used at the receiver. We report on the first demonstration of quantum key distribution using transition-edge sensors with high efficiency and negligible dark-count rates. Using two methods of synchronization, a bright optical pulse scheme and an electrical signal scheme, we have successfully distributed key material at 1,550 nm over 50 km of optical fiber. We discuss how use of these detectors in a quantum key distribution system can result in dramatic increases in range and performance.
@article{arxiv.quant-ph/0510062,
title = {Quantum key distribution at telecom wavelengths with noise-free detectors},
author = {Danna Rosenberg and Sae Woo Nam and Philip A. Hiskett and Charles G. Peterson and Richard J. Hughes and Jane E. Nordholt and Adriana E. Lita and Aaron J. Miller},
journal= {arXiv preprint arXiv:quant-ph/0510062},
year = {2009}
}