Quantum networks, which rely on the principles of quantum mechanics, are revolutionizing the domain of information technology. Through efficient distribution and utilization of quantum resources, the goal of quantum networks is to support diverse quantum information applications. However, existing quantum protocols face compatibility issues that limit functional scalability. In collaboration with the National Time Service Center, Chinese Academy of Sciences, we propose the collaborative implementation scheme of quantum key distribution and quantum time synchronization, by multiplexing the energy-time entangled biphotons and quantum channel. A proof-of-principle experiment between two independent nodes across a 120 km fiber is demonstrated, which achieves sub-picosecond synchronization stability based on the quantum two-way time transfer protocol. Simultaneously, this synchronization provides the required timing information for dispersive optics quantum key distribution with an average finite-size secure key rate of 73.8 bps. Furthermore, the performance degradation induced by asymmetric delay attacks in the quantum channel is effectively mitigated by the quantum time synchronization procedure. This work paves the way for a resource-efficient, function-scalable, and highly compatible quantum network. 

This work was published on Laser & Photonics Reviews (https://onlinelibrary.wiley.com/doi/10.1002/lpor.202500658) at 11 June 2025 with the title of “Towards a Function-Scalable Quantum Network With Multiplexed Energy-Time Entanglement”. Ph.D candidate Jingyuan Liu is the co-first author of this paper. Prof. Wei Zhang is the co-corresponding author of this paper.