Opt Lett. 2023 Jun 1;48(11):2953-2956. doi: 10.1364/OL.492082.
We experimentally demonstrate a high-rate discretely modulated continuous-variable quantum key distribution over 80-km standard single-mode fiber with a 2.5 Gbaud, 16-symbol, two-ring constellation. With the help of well-designed digital signal processing algorithms, the excess noise of the system can be effectively suppressed. The achieved secret key rates are 49.02 Mbits/s, 11.86 Mbits/s, and 2.11 Mbits/s over 25-km, 50-km, and 80-km optical fiber, respectively, and achieve 67.4%, 70.0%, and 66.5% of the secret key rate performance of a Gaussian-modulated protocol. Our work shows that it is feasible to build a high-performance, long-distance continuous-variable quantum key distribution system with only a small constellation size.
我们通过实验演示了一种在 80km 标准单模光纤上使用 2.5Gb/s、16 符号、双环星座的高速离散调制连续变量量子密钥分发。通过精心设计的数字信号处理算法，可以有效抑制系统的过剩噪声。在 25km、50km 和 80km 光纤上，分别实现了 49.02Mbits/s、11.86Mbits/s 和 2.11Mbits/s 的密钥率，并且达到了高斯调制协议密钥率性能的 67.4%、70.0%和 66.5%。我们的工作表明，仅使用较小的星座尺寸构建高性能、长距离连续变量量子密钥分发系统是可行的。
