Proof-of-principle demonstration of a decoy state experiment based on the mirror protocol

Decoy state semi-quantum key distribution (SQKD) has been proposed as a method aimed at significantly enhancing the security and performance of practical semi-quantum key distribution systems. However, the gap between theory and experiment remains open. Herein, we propose the decoy state setting and experimental scheme for the mirror protocol and conduct the proof-of-principle demonstration experiment of the decoy state mirror protocol. The simulation results, obtained under experimental conditions, demonstrate that no key generation rate can be generated under the conditions of the Gottesman-Lo-Lütkenhaus-Preskill (GLLP) and one-decoy state, while valid key generation rates are achievable within a fiber transmission distance of 19.1 km under the weak and vacuum states. Furthermore, it was experimentally verified that a key generation rate of 406 bits/s can be achieved under the combined conditions of weak and vacuum states and a 10 km fiber channel. As the first, to the best of our knowledge, proof-of-principle demonstration of the decoy state mirror protocol, this study lays a foundation for the practical security analysis of SQKD from an experimental perspective and serves as an important starting point for the practical verification in this field.