Jiao Rong-Zhen

Performance of a superconducting single photon detector with nano-antenna

The performance of single-photon detectors can be enhanced by using nano-antenna. The characteristics of the superconducting nano-wire single-photon detector with cavity plus anti-reflect coating and specially designed nano-antenna is analysed. The photon collection efficiency of the detector is enhanced without damaging the detectors speed, thus getting rid of the dilemma of speed and efficiency. The characteristics of nano-antenna are discussed, such as the position and the effect of the active area, and the best result is given. The photon collection efficiency is increased by 92 times compared with that of existing detectors.

Analysis statistical fluctuation for quantum key distribution system

Every security analysis of quantum key distribution relies on a faithful modeling of the employed quantum states. The properties of decoy state protocol based on only two decoy states and one signal state are analyzed. The performance of decoy state quantum key distribution protocol with finite resources is calculated by considering the statistical fluctuation for the yield and error rate of the quantum state. The relationship between key generation rate and transmission distance is compared by considering the data-set size to be N=108 (N=109 or N=1010 or the asymptotic case). These may provide some important parameters for the practical quantum key distribution system.

Analysis of the differential-phase-shift-keying protocol in the quantum-key-distribution system

The analysis is based on the error rate and the secure communication rate as functions of distance for three quantum-key-distribution (QKD) protocols: the Bennett–Brassard 1984, the Bennett–Brassard–Mermin 1992, and the coherent differential-phase-shift keying (DPSK) protocols. We consider the secure communication rate of the DPSK protocol against an arbitrary individual attack, including the most commonly considered intercept-resend and photon-number splitting attacks, and concluded that the simple and efficient differential-phase-shift-keying protocol allows for more than 200 km of secure communication distance with high communication rates.

Performance of Differential-Phase-Shift Keying Protocol Applying 1310 nm Up-Conversion Single-Photon Detector

The performance of the differential-phase-shift keying (DPSK) protocol applying a 1310 nm up-conversion single-photon detector is analysed. The error rate and the communication rate as a function of distance for three quantum key distribution protocols, the Bennett–Brassard 1984, the Bennett–Brassard–Mermin 1992, and the DPSK, are presented. Then we compare the performance of these three protocols using the 1310nm up-conversion detector. We draw the conclusion that the DPSK protocol applying the detector has significant advantage over the other two protocols. Longer transmission distance and lower error rate can be achieved.

Performance of superconducting nanowire single-photon detector with the fan coupling antenna array

The performance of superconducting nanowire single-photon detector (SNSPD) involving niobium nitride with the fan coupling antenna array is analyzed. The SNSPD has a high detection efficiency and counting rate. Hydrogen silsesquioxane and niobium nitride are filled in the gold grating deposited on the substrate in which the fan coupling antenna arrays are embedded. By changing the position of the fan coupling antenna array, the maximum area of optical intensity is obtained and the photon collection efficiency is increased by 26.5 times. The detection efficiency of SNSPD is improved without changing the detection speed. These parameters are important for designing a practical single-photon detector.

Fluctuation Analysis of Decoy State QKD with Finite Data-Set Size

Decoy state method quantum key distribution (QKD) is one of the promising practical solutions for BB84 QKD with coherent light pulses. The number of data-set size in practical QKD protocol is always finite, which will cause statistical fluctuations. In this paper, we apply absolutely statistical fluctuation to amend the yield and error rate of the quantum state. The relationship between exchanged number of quantum signals and key generation rate is analyzed in our simulation, which offers a useful reference for experiment.

Performance of various quantum-key-distribution systems using 1550nm up-conversion single-photon detectors

We compare the performance of various quantum-key-distribution (QKD) systems using 1550 nm up-conversion single-photon detectors. The analysis is based on the error rate and the secure communication rate as a function of distance for three QKD protocols: the Bennett-Brassard 1984, the Beruiett-Brassard-Vlerinin 1992, and the coherent differential-phase-shift keying (DPSK) protocols. We discussed that the security of DPSK protocol against any type of individual photon splitting attack and concluded that the simple and efficient DPSK protocol allows for more than 200 km of secure communication distance with high communication rates.