We have proposed and experimentally demonstrated an ultrasensitive all-fiber angular displacement sensor based on in-fiber polarizing gratings and half waveplate (IFHWP), in which the polarizing gratings are based on 45°-tilted fiber gratings (45°-TFGs) and the IFHWP is constructed by bending-induced birefringence in single mode fiber (SMF). Compared with the existing angular displacement sensors, the structure of our proposed sensor is more desirable to bring the prominent advantages of all-fiber structure, low transmission loss and high sensitivity. The experimental results show that the proposed angular displacement sensor has a sensitivity and a resolution up to 20.477 dB/rad and $2.8\times 10^{-3\circ }$ , respectively, within a large measurement range of about 25°. In addition, such sensor also has very low temperature sensitivity around $2.1\times 10^{-4}$ dB/°C.

中文翻译：

---

基于偏振光栅的超灵敏全光纤角位移传感器

我们已经提出并实验证明了一种基于光纤内偏振光栅和半波片 (IFHWP) 的超灵敏全光纤角位移传感器，其中偏振光栅基于 45°倾斜光纤光栅 (45°-TFG) 和IFHWP 由单模光纤 (SMF) 中的弯曲诱导双折射构成。与现有的角位移传感器相比，我们提出的传感器结构更具有全光纤结构、低传输损耗和高灵敏度的突出优点。实验结果表明，所提出的角位移传感器具有高达 20.477 dB/rad 的灵敏度和分辨率，并且 $2.8\times 10^{-3\circ }$ ，分别在大约 25° 的大测量范围内。此外，这种传感器周围的温度灵敏度也非常低。 $2.1\乘以 10^{-4}$ 分贝/°C。