Recently, Pan Jianwei and Chen Teng-Yun of the University of Science and Technology of China (USTC) and Ma Xiong-Feng of Tsinghua University collaborated to experimentally realize Mode-pairing Quantum Key Distribution (QKD) for the first time, and the related research results were published in Physical Review Letters on Jan. 17.
It is understood that quantum key distribution (QKD) is based on the basic principles of quantum mechanics and can achieve theoretically unconditionally secure and confidential communication, so it has been a hot research topic in academia in recent decades.
Pattern matching quantum key distribution protocol (MP-QKD) is a new measurement device-independent quantum key distribution protocol proposed by Ma Xiongfeng’s research group at Tsinghua University in 2022. Compared with the original measurement device-independent protocol (MDI-QKD), MP-QKD can use more detection events for code formation, which can improve the code formation rate to a great extent.
At the same time, compared with the two-field quantum key distribution protocol (TF-QKD) and phase-matching protocol (PM-QKD), MP-QKD does not require complex laser frequency-locking and phase-locking technology, which saves cost and reduces practical application difficulties, and has better anti-interference capability against environmental noise.
Schematic diagram of the pattern-matching quantum key distribution protocol
Based on the mode matching quantum key distribution (MP-QKD) protocol proposed by Ma Xiongfeng’s group at Tsinghua University, Pan Jianwei’s and Chen Tengyun’s groups precisely estimated the frequency difference of two independent lasers for parameter estimation using the data post-processing method of great likelihood estimation, and combined with the high-efficiency single photon detector developed by You Lixing’s group at Shanghai Institute of Microsystems, Chinese Academy of Sciences, realized the secure code-formation of standard fiber at 100 km level, 200 km level, 300 km level and ultra-low loss fiber at 400 km level. The coding rate is significantly improved compared with the original MDI experiments, and the coding rate is improved by three orders of magnitude at 300 km and 400 km distances compared with the previous experiments.
Comparison of code-formation rates of pattern matching protocols
The above research results show that MP-QKD can achieve safe code-forming at long distances and high code-forming rates at metropolitan distances without laser frequency locking, which greatly reduces the difficulty of protocol implementation and is of great significance for the construction of future quantum communication networks.
