Low-cost temperature- and strain-insensitive twist sensor based on a hybrid fiber grating structure

摘要

We proposed and experimentally demonstrated a temperature- and strain-insensitive twist sensor based on a hybrid fiber grating structure, in which the hybrid grating structure is constructed with a 45 degrees-tilted fiber grating and a chirped fiber Bragg grating UV-inscribed in a single-mode fiber in series. The sensing performance has been evaluated by experimental and numerical analyses, which are in good consistency. The experimental results show that the hybrid-grating-structure-based twist sensor has a maximum twist sensitivity up to 15.037 dB/rad. Moreover, due to the invariability of the fiber birefringence and the state of polarization of the input light, such sensor has intrinsically low temperature and strain sensitivities of 7.86 x 10(-3) dB/degrees C and 6.7 x 10(-5) dB/mu epsilon, corresponding to the maximum twist measurement error resulting from temperature and strain of 5.2 x 10(-4) rad/degrees C and 4.5 x 10(-6) rad/mu epsilon, respectively. (c) 2019 Optical Society of America.