Simple and Fast Polarization Tracking Algorithm for Continuous-Variable Quantum Key Distribution System Using Orthogonal Pilot Tone

作者：Yan Pan, Heng Wang, Yun Shao, Yaodi Pi, Ting Ye, Shuai Zhang, Yang Li, Wei Huang, Bingjie Xu · 发表于：Journal of Lightwave Technology · 年份：2023 · DOI：10.1109/jlt.2023.3277982 · 被引用次数：16 · 研究领域：Optical Network Technologies、Quantum Information and Cryptography、Photonic and Optical Devices

To reduce the influence of random channel polarization variation, especially fast polarization perturbation, for continuous-variable quantum key distribution (CV-QKD) systems, a simple and fast polarization tracking algorithm is proposed and experimentally demonstrated. The algorithm is implemented by an orthogonal pilot tone scheme, one of the pilot tones is used for estimating the polarization rotation angle, and the other one is used for compensating the polarization perturbation introduced phase noise. Meanwhile, residual effects are compensated precisely with the help of a real-valued FIR filter. In this case, the excess noise introduced by polarization perturbation is effectively suppressed. Experimental results show that the polarization scrambling rate ≥12.57 krad/s can be tracked by using the proposed algorithm, and a good estimated parameters performance is achieved. Compared to conventional polarization tracking algorithms such as the constant modulus algorithm (CMA), experimental results show that the polarization tracking capability of the proposed algorithm is significantly improved. Furthermore, much faster polarization tracking performance is evaluated by digital simulations, and the simulation results show that about 188.50 Mrad/s can be tracked by the proposed algorithm. Thus, our method provides effective technology for the practical application of fiber-based CV-QKD.