In this study, a high-sensitivity, high-spatial-resolution distributed strain-sensing approach based on a poly(methyl methacrylate) chirped fiber Bragg grating (CFBG) is proposed and experimentally demonstrated. Linearly chirped FBGs in a polymer optical fiber provide an alternative to the silica fiber owing to the lower Young’s modulus, which can yield a higher stress sensitivity under the same external force. According to the spatial wavelength-encoded characteristic of the CFBG, a fully distributed strain measurement can be achieved by optical frequency-domain reflectometry. Through time-/space-resolved short-time Fourier transform, the applied force can be located by the beat frequency originated from the space-induced time delay and measured by the differential frequency offset originated from the strain-induced dispersion time delay. In a proof-of-concept experiment, a high spatial resolution of 1 mm over a gauge length of 40 mm and a strain resolution of 0.491 Hz/μe were achieved.

中文翻译：

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基于聚甲基丙烯酸甲酯啁啾光纤布拉格光栅的高灵敏度高空间分辨率分布式应变传感

在这项研究中，提出并实验证明了一种基于聚（甲基丙烯酸甲酯）啁啾光纤布拉格光栅（CFBG）的高灵敏度、高空间分辨率分布式应变传感方法。由于较低的杨氏模量，聚合物光纤中的线性啁啾光纤光栅提供了石英光纤的替代品，在相同的外力下可以产生更高的应力敏感性。根据CFBG的空间波长编码特性，可以通过光频域反射法实现全分布应变测量。通过时间/空间分辨短时傅立叶变换，可以通过源自空间引起的时间延迟的拍频来定位所施加的力，并通过源自应变引起的色散时间延迟的差分频率偏移量来测量。