https://doi.org/10.1140/epjqt/s40507-023-00207-9
Research
Demonstration of 75 km-fiber quantum clock synchronization in quantum entanglement distribution network
1
College of Advanced Interdisciplinary Studies, National University of Defense Technology, Changsha, China
2
Strategic Assessments and Consultation Institute, Academy of Military Science, Beijing, China
3
College of Computer, National University of Defense Technology, Changsha, China
4
College of Sciences, National University of Defense Technology, Changsha, China
5
National Time Service Center, Chinese Academy of Sciences, Xi’an, China
j
liubo08@nudt.edu.cn
k
wlyu@nudt.edu.cn
Received:
24
July
2023
Accepted:
17
November
2023
Published online:
22
November
2023
The quantum entanglement distribution network, serviced as the communication infrastructure which distributes quantum information among remote users, enables many applications beyond the reach of classical networks. Recently, the applications such as quantum key distribution and quantum secure direct communication, have been successfully demonstrated in the quantum entanglement distribution network. In this article, we propose a multi-user round-trip quantum clock synchronization (QCS) scheme in the quantum network, which can be implemented with one single entangled photon source located at the server. The server distributes the entangled photons to remote multiple users with the wavelength division multiplexing strategy, and each user feeds partial received photons back to the server. The clock difference between the server and each user is calculated from the one-way and round-trip propagation times, which are determined according to the time correlation of entangled photons. Afterwards, the demonstration has been conducted between the server and a user over a 75-km-long fiber link, where the measured clock difference uncertainty is 4.45 ps, and the time deviation is 426 fs with an average time of 4000 s. Furthermore, the proposed QCS scheme is linearly scalable to many users, with respect to user hardware and number of deployed fibers.
Key words: Quantum entanglement distribution network / Quantum clock synchronization / Multi-user / Round-trip
Bang-Ying Tang and Ming Tian contributed equally to this work.
© The Author(s) 2023
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