为了解决光纤光栅在低温环境中的应用问题, 该文从光纤布喇格光栅(FBG)的传感理论出发, 通过深入分析了FBG在-60~25 ℃时热光系数和热膨胀系数的变化。采用2根未封装的FBG进行实验验证, 得到了FBG在低温环境下的响应情况。研究结果表明, FBG在低温环境下具有良好的响应和重复性, 这对FBG在低温环境中的应用具有重要指导意义。

针对两点封装, 建立光纤光栅加速度检波器通用模型, 理论推导加速度检波器灵敏度和谐振频率的解析表达式, 深入研究加速度灵敏度和谐振频率的影响因素, 讨论封装光纤刚度系数与检波器结构刚度系数之比对检波器响应特性的影响, 并分析刚度比分别在0~1、0~100范围随着等效质量的增大(0 g~100 g), 加速度灵敏度和谐振频率的制约关系, 及在0 Hz~500 Hz(中低频)和0 Hz~1 200 Hz(中高频)范围内灵敏度的变化规律。此外, 分别以封装光纤长度为10 mm和60 mm举例分析长度对上述二者的影响, 各项仿真中灵敏度均会高达~1 000 pm/G, 并引入品质因数的概念。所提理论研究对FBG加速度检波器的设计和综合性能的评价具有重要的指导意义, 为器件参数优化提供理论依据。

The reflective spectrum power and the bandwidth of the fiber Bragg grating (FBG) under gradient strain are researched and experimentally demonstrated. The gradient strain is applied on the FBG, which can induce FBG bandwidth broadening, resulting in the variation of reflective power. Based on the coupled-mode theory and transfer matrix method, the segmental linear relationship between the gradient strain, the reflective power, and the bandwidth is simulated and analyzed, and the influence of the FBG length on the reflective spectrum is analyzed. In the experiment, the strict gradient stain device is designed; the experimental results indicate that the reflective optic power and the bandwidth of the FBG under gradient stain are concerned with the length of the FBG. Experimental results are well consistent with the theoretical analysis, which have important guiding significance in the FBG dynamic sensing.

光纤Bragg光栅流量传感器是基于光信号的新型流量传感器。当光纤光栅受到流体的作用时, 其波长、相位都会发生变化, 通过检测光信号的变化就可得到外界流量的变化。文章主要介绍了几种光纤光栅流量传感器的工作机理, 分析了各种流量传感器的优缺点, 并对光纤光栅流量传感器的发展进行了展望。