Low-complexity CV-QKD system with optical pilot-tone local oscillator synchronization

This study presents a comprehensive simulation-based analysis of optical pilot tone generation for local oscillator synchronization in continuous-variable quantum key distribution (CV-QKD) systems using Gaussian-modulated (GM) coherent states. We compare system performance when the pilot tone is generated either electrically or optically, examining the effects of key parameters such as pilot tone power, laser linewidth, digital-to-analog converter resolution, and link distance. The results provide insights into pilot tone generation strategies that enhance robustness while reducing the implementation complexity of GM CV-QKD systems.