ABSTRACT: A short survey on experimental works in quantum cryptography is presented. We describe experimental setups that were designed
in the Institute of Semiconductor Physics, Siberian Branch of the Russian Academy of Sciences, for quantum key distribution
through an air space and along a fiber-optic communication line. The results of the study of quantum efficiency parameters,
probability of afterpulse appearance, and noise levels for different operation modes of InGaAs-InP avalanche photodiodes are
Russian Microelectronics 04/2012; 40(4):245-253.
ABSTRACT: This paper gives experimental results of quantum key distribution on a fiber-optic setup at a telecom wavelength of 1555 nm.
A self-compensated two-channel 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 high-sensitivity 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 single-mode fiber-optic
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%.
Optoelectronics Instrumentation and Data Processing 04/2012; 45(4):374-381.
ABSTRACT: A brief overview of the current status of quantum cryptography is given. The results are presented of our preliminary experiments
with free-space quantum-key distribution by means of single linearly polarized photons with coded polarization states according
to the BB84 protocol, for which purpose a quantum-cryptography communication system is designed. Single photons are detected
with a 50% probability using specially designed high-speed photodetectors based on silicon avalanche photodiodes, operated
in Geiger mode with active avalanche quenching. A key generation rate of 3.8 kbit/s is obtained, the mean photon number per
pulse being 0.2.
Russian Microelectronics 12/2005; 35(1):31-36.
ABSTRACT: Pioneering experiments on single-photon quantum cryptography that are performed with a tailored setup are reported. The key
is transferred by pulsed semiconductor lasers, which encode the polarization state of the photons in two mutually nonorthogonal
bases. Photon detectors are based on C30902S silicon avalanche photodiodes. For a laser pulse repetition rate of 100 kHz and
a mean number of photons per pulse of about 0.2, the key generation rate reaches ≈4 kbit/s. The error rate in the key does
not exceed 1%.
Technical Physics 05/2005; 50(6):727-731. · 0.50 Impact Factor
ABSTRACT: This paper reports on the results of experimental investigations into the distribution of a quantum key on a setup designed
for quantum cryptography with single photons. The quantum key is transmitted with pulsed semiconductor lasers by coding polarization
states of photons in two alternative nonorthogonal bases. Silicon avalanche photodiodes (C30902S) serve as single-photon detectors.
The rate of key generation is equal to 1.8 kbit/s when the clock frequency of laser pulse repetition is 100 kHz and the mean
number of photons per pulse is approximately equal to 0.2. The number of errors in the key does not exceed 1%.
Optics and Spectroscopy 08/2004; 96(5):703-706. · 0.61 Impact Factor