We propose a frequency-division multiplexed (FDM) continuous-variable quantum key distribution (CV-QKD) system with enhanced spectral efficiency through dense multiplexing of low-symbol-rate signals. A four-channel 10-Mbaud FDM-CV-QKD system was experimentally demonstrated using Gaussian modulation, a transmitted local oscillator, and homodyne detection. Under a finite-size scenario (N = 10^7), the system achieved a 3.7-fold back-to-back secret key rate gain and outperformed the single-channel system for distances up to 41.1 km.

翻译：我们提出了一种频分复用连续变量量子密钥分发系统，通过密集复用低符号速率信号提升了频谱效率。实验演示了采用高斯调制、传输本振及零差探测的四通道10兆波特频分复用连续变量量子密钥分发系统。在有限尺寸场景（N=10^7）下，该系统实现了3.7倍背靠背密钥率增益，并在长达41.1公里距离内性能优于单通道系统。