Imperfect state preparation in continuous-variable quantum key distribution

Wenyuan Liu, Xuyang Wang, Ning Wang, Shanna Du, and Yongmin Li
Phys. Rev. A 96, 042312 – Published 11 October 2017

Abstract

In continuous-variable quantum key distribution, the loss and excess noise of the quantum channel are key parameters that determine the secure key rate and the maximal distribution distance. We investigate the imperfect quantum state preparation in Gaussian modulation coherent-state protocol both theoretically and experimentally. We show that the Gaussian distribution characteristic of the prepared states in phase space is broken due to the incorrect calibration of the working parameters for the amplitude modulator and phase modulator. This further causes a significant increase of the excess noise and misestimate of the channel loss. To ensure an accurate estimate of the quantum channel parameters and achieve a reliable quantum key distribution, we propose and demonstrate two effective schemes to calibrate the working parameters of the modulators.

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  • Received 11 July 2017

DOI:https://doi.org/10.1103/PhysRevA.96.042312

©2017 American Physical Society

Physics Subject Headings (PhySH)

Atomic, Molecular & OpticalQuantum Information, Science & Technology

Authors & Affiliations

Wenyuan Liu1, Xuyang Wang1,2, Ning Wang1, Shanna Du1, and Yongmin Li1,2,*

  • 1State Key Laboratory of Quantum Optics and Quantum Optics Devices, Institute of Opto-Electronics, Shanxi University, Taiyuan 030006, China
  • 2Collaborative Innovation Center of Extreme Optics, Shanxi University, Taiyuan 030006, China

  • *yongmin@sxu.edu.cn

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Issue

Vol. 96, Iss. 4 — October 2017

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