Chinese Journal of Quantum Electronics ›› 2024, Vol. 41 ›› Issue (6): 933-941.doi: 10.3969/j.issn.1007-5461.2024.06.010

• Quantum Optics • Previous Articles     Next Articles

Time synchronization method for quantum communication based on time⁃frequency domain

SHEN Wei, LIU Weiyue *   

  1. College of Information Science and Engineering, Ningbo University, Ningbo 315211, China
  • Received:2022-12-05 Revised:2023-01-13 Published:2024-11-28 Online:2024-11-28

Abstract: Time synchronization is crucial for satellite-to-ground quantum key distribution (QKD). To overcome the noise interference and the loss of quantum light signal in satellite-to-ground QKD, previous schemes used global positioning system (GPS) equipment to assist synchronous light mapping. In order to reduce the complexity and cost of the system, a time synchronization method combining time domain and frequency domain is proposed in this paper. The method utilizes the spectral characteristics of quantum light and linear fitting method to achieve high precision time synchronization. The method is tested with the experimental data of satellite-to-ground QKD, a synchronization accuracy of 1.03 ns can be achieved, and a full width at half maximum of the histogram is 1.4 ns. The method does not require the use of GPS and synchronous light, and can be widely used in satellite-to-ground QKD.

Key words: quantum optics, clock self-recovery, linear fitting, quantum key distribution, time synchronization

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