Using SinglePhoton Detectors for Quantum Key Distribution in an Experimental FiberOptic Communication System
V. L. Kurochkin, A. V. Zverev, Y. V. Kurochkin, I. I. Ryabtsev, I. G. Neizvestny
Keywords: quantum computer science, quantum cryptography, singlephoton detectors
Pages: 110119
Abstract
This paper gives experimental results of quantum key distribution on a fiberoptic setup at a telecom wavelength of 1555 nm. A selfcompensated twochannel optical circuit is used. Quantum key distribution was performed by coding the phase states of single photons radiated by a pulsed semiconductor laser in two alternative nonorthogonal bases. Specially developed single photon counters based on InGaAs:InP avalanche photodiodes were employed as highsensitivity photodetectors. The results of investigation of the quantum efficiency, probability of afterpulses, and noise level for various operating modes of the detectors at temperatures from −40 to −60 °C are given. A key distribution rate of 450 bit/s was obtained for a singlemode fiberoptic quantum communication channel between the receiver and sender 25 km long at a laser pulse clock frequency of 5 MHz and an average number of photons per pulse of about 0.2. For the achieved photodetector characteristics, the average number of errors in the quantum key did not exceed 3.7 %.
