High-dimensional quantum key distribution with statistical and intensity fluctuations

ABSTRACT High-dimensional quantum key distribution (HD-QKD) can higher the secret-key capacity and tolerate more errors. Several HD-QKD experiments have been demonstrated over deployed fibers to show promising future toward high-dimensional quantum communication networks. However, the practical security of HD-QKD systems should be widely considered before large-scale application of HD-QKD systems. In this paper, we focus on the HD-QKD based on the dispersive optics (DO-QKD) with both statistical and intensity fluctuations. For the condition only with statistical fluctuations, we present the parameter estimation based on an improved Chernoff bound. When considering the condition with both statistical and intensity fluctuations, we present the parameter estimation based on Azuma’s inequality. By numerical simulations, we find that the parameter estimation for DO-QKD based on the improved Chernoff bound is tighter than the previous work in terms of the secret-key capacity and the maximum transmission distance. Moreover, we find that intensity fluctuations affect the performance of DO-QKD greatly and the effect on smaller data size is more obvious.