Polarizing Grating-Based Ultrasensitive All-Fiber Angular Displacement Sensor

Abstract

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.