Finite-key analysis of practical time-bin high-dimensional quantum key distribution with afterpulse effect

• Published in: Chinese physics B Vol. 31; no. 8; pp. 80303 - 266
• Main Authors: Zhou, Yu, Zhou, Chun, Wang, Yang, Lu, Yi-Fei, Jiang, Mu-Sheng, Zhang, Xiao-Xu, Bao, Wan-Su
• Format: Journal Article
• Language: English
• Published: Chinese Physical Society and IOP Publishing Ltd 01.08.2022; Synergetic Innovation Center of Quantum Information and Quantum Physics,University of Science and Technology of China,Hefei 230026,China; Henan Key Laboratory of Quantum Information and Cryptography,SSFIEU,Zhengzhou 450001,China
• Subjects: afterpulse effect; finite-key analysis; high-dimensional; intensity fluctuations; time-bin; high-dimensional; afterpulse effect; intensity fluctuations; time-bin; finite-key analysis
• ISSN: 1674-1056
• DOI: 10.1088/1674-1056/ac6017

High-dimensional quantum resources provide the ability to encode several bits of information on a single photon, which can particularly increase the secret key rate rate of quantum key distribution (QKD) systems. Recently, a practical four-dimensional QKD scheme based on time-bin quantum photonic state, only with two single-photon avalanche detectors as measurement setup, has been proven to have a superior performance than the qubit-based one. In this paper, we extend the results to our proposed eight-dimensional scheme. Then, we consider two main practical factors to improve its secret key bound. Concretely, we take the afterpulse effect into account and apply a finite-key analysis with the intensity fluctuations. Our secret bounds give consideration to both the intensity fluctuations and the afterpulse effect for the high-dimensional QKD systems. Numerical simulations show the bound of eight-dimensional QKD scheme is more robust to the intensity fluctuations but more sensitive to the afterpulse effect than the four-dimensional one.