AI 中文总结
研究偏振编码量子通信中光链路偏振变换补偿问题，提出用四波片补偿器和八斯托克斯矢量协议，能在宽波长范围合成变换、重建矩阵，实验表明该方案可抑制误码率，支持灵活放置补偿器和选择波长信道等。
AI 中文摘要
偏振编码量子通信需要补偿光链路引起的偏振变换。若补偿器嵌入两信道段间，其前后变换须分别处理。此外，标准三波片偏振控制器在相位延迟偏离理想值时会变得非通用。为应对这两个挑战，我们引入了一种能在宽波长范围内合成任意SO(3)偏振变换的四波片补偿器，以及一种能重建补偿器两侧两个链路段穆勒矩阵的八斯托克斯矢量协议。我们的实验表明，在距设计波长超过100 nm的工作波长下，四波片序列无需进一步优化就能将偏振诱导过量量子比特误码率（QBER）抑制到亚百分比水平。结合两个辅助波长，我们的方案能跟踪强波长敏感光纤线轴的温度驱动漂移，同时将过量QBER保持在1%以下。这些结果支持了灵活的补偿器放置和波长信道选择，以及波分复用量子光链路中的无中断偏振控制。
英文摘要
Polarization-encoded quantum communication requires compensation of polarization transformations induced by the optical links. If the compensator is embedded between two channel segments, the transformations before and after the compensator must be treated separately. Moreover, standard three-wave-plate polarization controllers can become non-universal when their retardances deviate from their ideal values. To address these two challenges, we introduce a four-wave plate compensator that synthesizes arbitrary SO(3) polarization transformations over a broad wavelength range, and an eight-Stokes vector protocol that reconstructs the two link-segment Mueller matrices on either side of the compensator. Our experiment reveals that the four-plate sequence suppresses polarization-induced excess quantum bit error rate (QBER) to the sub-percent level at an operating wavelength more than 100 nm from the design wavelength without further optimization. Combined with two auxiliary wavelengths, our scheme tracks the temperature-driven drift of a strongly wavelength-sensitive fiber spool while keeping the excess QBER below 1%. These results support flexible compensator placement and wavelength channel selection, as well as non-interruptive polarization control in wavelength-division-multiplexed quantum optical links.
