In practical satellite-based quantum key distribution (QKD) systems, the preparation and transmission of polarization-encoding photons suffer from complex environmental effects and high channel-loss. Consequently, the hinge to enhancing the secure key rate (SKR) lies in achieving robust, low-error and high-speed polarization modulation. Although the schemes that realize self-compensation exhibit remarkable robustness. Their modulation speed is constrained to approximately 2 GHz to avoid the interaction between the electrical signal and the reverse optical pulses. Here we utilize the non-reciprocity of the lithium niobate modulators and eliminate the modulation on the reverse optical pulses. As this characteristic is widely available in the radio-frequency band, the modulation speed is no longer limited by the self-compensating optics and can be further increased. The measured average intrinsic QBER of the different polarization states at 10 GHz system repetition frequency is as low as 0.53% over 10 min without any compensation. And the experiment simulation shows that the proposed scheme extends the transmission distance to more than 350 km. Our work can be be efficient performed to the high-speed and high-loss satellite-based quantum communication scenario.
@article{arxiv.2411.08358,
title = {10 GHz Robust polarization modulation towards high-speed satellite-based quantum communication},
author = {Zexu Wang and Huaxing Xu and Ju Li and Jinquan Huang and Hui Han and Changlei Wang and Ping Zhang and Feifei Yin and Kun Xu and Bo Liu and Yitang Dai},
journal= {arXiv preprint arXiv:2411.08358},
year = {2024}
}