Parameter optimization of SQCC-CVQKD based on genetic algorithm in the terahertz band

Recently, we proposed a continuous variable quantum key distribution (CVQKD) scheme based on simultaneous quantum and classical communication (SQCC) in the terahertz (THz) band. It performs classical modulation and quantum Gaussian modulation at the same coherent pulse at the sending end, and an amplifier is used to amplify and demultiplex the signal at the receiving end. However, the previous study set parameters based on prior knowledge which has significant limitations, and as the previous study showed, parameter selection is a crucial task that directly affects the performance of the system. In this paper, we use the genetic algorithm to optimize the parameter selection, and how the different conditions influence the optimal value of parameters is also analyzed. The simulation results show that the parameter optimized with the algorithm can make the scheme achieve a higher secret key rate which greatly improves the applicability of the SQCC scheme in the THz band. This work demonstrates the effectiveness of the scheme to construct wireless quantum communication networks.