AI 中文总结
本研究提出并验证联合相位与双折射估计的MIMO-DAS系统数值模型，采用偏振复用编码序列实现与WDM传输共存，可估计静态及动态应变下的双折射与相位，提升扰动检测灵敏度。
AI 中文摘要
本研究提出并实验验证了一种多输入多输出分布式声学传感（MIMO-DAS）系统的数值模型，该模型考虑了光纤双折射的动态扰动以及背向散射信号的公共光相位（即偏振分支共享的偏振平均相位）的动态扰动。MIMO-DAS系统采用偏振复用恒功率编码序列探测光纤，该序列适用于DAS与同一光纤上的WDM数据传输共存。研究了轴对称和各向异性事件对上述两个量的影响。通过数值模拟和实验室实验，演示了静态条件下有效双折射幅值的估计，以及动态纵向应变和各向异性横向应变下公共相位与有效双折射幅值的联合估计。这实现了事件判别，并提高了对光纤横向扰动的灵敏度，因为偏振对破坏圆柱对称性的扰动有响应，而相位对纵向应变有强响应。
英文摘要
In this work, we introduce and experimentally validate a numerical model for a Multiple-Input-Multiple-Output Distributed Acoustic Sensing (MIMO-DAS) system that accounts for dynamic perturbations of fiber birefringence and of the common optical phase of the backscattered signal (or polarization-averaged phase, shared by both polarization tributaries). The MIMO-DAS system probes the fiber using polarization-multiplexed constant-power coded sequences that are suited for coexistence of DAS with WDM data transmission over the same fiber. We study the effect of both axisymmetric and anisotropic events on the two quantities. We demonstrate, through numerical simulations and lab experiments, the estimation of effective birefringence magnitude in static conditions, and the joint estimation of common phase and effective birefringence magnitude in the case of dynamic longitudinal strain and anisotropic transverse strain. This allows for event discrimination and increased sensitivity to disturbances that act transversely on the fiber, since polarization will be responsive to perturbations that break cylindrical symmetry, while the phase will strongly respond to longitudinal strain.
