📝 SummarXiv

Abstract

The limited bandwidth of optical devices places strict constraints on the performance of quantum key distribution (QKD) systems. Excessively high clock rates can result in misaligned and correlated modulation, compromising security and increasing error rates. In this paper, we present two innovative techniques that enable the precise characterization and mitigation of these imperfections at ultra-low levels. When combined with a security analysis that accommodates residual flaws, our approach ensures the security of high-rate QKD systems and outperforms existing solutions. Notably, our method achieves the lowest correlated deviation reported to date in comparable studies and surpasses the conventional, bandwidth-limited secret key rate. This advance is a significant step towards eliminating the performance-cost trade-off, paving the way for the practical deployment of QKD.