Bending Vector Sensor Based on a Sector-Shaped Long-Period Grating

Abstract

A novel optical fiber grating vector bending sensor head is proposed. The asymmetric characteristics are embedded in the sensor head by tilting the grating planes at increasing angles, as moving away from the center grid of the structure. A high-frequency-CO <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> -laser is used to fabricate the sensor head. Due to the characteristics of the asymmetric structure, the bending sensitivity for the curvature range from -2 to 0 m <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">-1</sup> reaches 8.53 nm/ m <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">-1</sup> , and for the curvature range from 0 to 2 m <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">-1</sup> reaches 2.82 nm/ m <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">-1</sup> , respectively.