This Letter presents an ultrahigh resolution optic fiber strain sensor. A random distributed feedback fiber laser (RDFL) is locked by the proposed frequency-shift Pound–Drever–Hall technique, which tracks the resonant frequency change of a $\pi$-phase-shifted fiber Bragg grating. The random distributed feedback for the RDFL gives a Lorentzian envelope over the original laser frequency noise, which can suppress the thermally induced frequency noise. The frequency noise of the laser is reduced from about 100 to 20 Hz/√Hz at 1 kHz. An ultrahigh dynamic strain resolution of $140\mathrm{f\epsilon }/\surd \mathrm{Hz}\text{at}1\mathrm{kHz}$ is achieved.

中文翻译：

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带有锁频随机分布反馈光纤激光器的超高分辨率光纤应变传感器

这封信提出了一种超高分辨率的光纤应变传感器。所提出的移频Pound–Drever–Hall技术可锁定随机分布反馈光纤激光器（RDFL），该技术可跟踪光纤的谐振频率变化。$\pi$相移光纤布拉格光栅。RDFL的随机分布反馈给出了原始激光频率噪声的洛伦兹包络，从而可以抑制由热引起的频率噪声。激光的频率噪声在1 kHz时从约100 Hz降低到20 Hz /√Hz。超高动态应变分辨率$140\mathrm{f\epsilon }/\surd \mathrm{赫兹}\text{在}\mathrm{1个}\mathrm{千赫}$ 已完成。