Differential phase shift quantum key distribution using single-photon detectors based on a sinusoidally gated InGaAs/InP avalanche photodiode

The authors report a quantum key distribution experiment, in which they implemented a differential phase shift quantum key distribution protocol, using single-photon detectors based on InGaAs/InP avalanche photodiodes operated with a sinusoidal gating. The single-photon detectors were operated at a repetition frequency of 500 MHz with low after pulsing probabilities and low dark counts. A sifted key generation rate of 1.5 Mbit/s was achieved over a communication distance of 15 km. Taking account of the security of the protocol against general individual attacks, secure keys can be generated with a rate of 0.33 Mbit/s. (c) 2007 American Institute of Physics.