Experimental measurement-device-independent quantum key distribution with the double-scanning method

The measurement-device-independent quantum key distribution (MDI-QKD) can be immune to all detector side-channel attacks. Moreover, it can be easily implemented combining with the matured decoy-state methods under current technology. It, thus, seems a very promising candidate in practical implementation of quantum communications. However, it suffers from a severe finite-data-size effect in most existing MDI-QKD protocols, resulting in relatively low key rates. Recently, Jiang et al. [Phys. Rev. A103, 012402 (2021).PLRAAN1050-294710.1103/PhysRevA.103.012402] proposed a double-scanning method to drastically increase the key rate of MDI-QKD. Based on Jiang et al.'s theoretical work, here we for the first time, to the best of our knowledge, implement the double-scanning method into MDI-QKD and carry out corresponding experimental demonstration. With a moderate number of pulses of 10¹⁰, we can achieve 150 km secure transmission distance, which is impossible with all former methods. Therefore, our present work paves the way toward practical implementation of MDI-QKD.