A novel torsion sensor based on helical tilted long-period fiber grating

Abstract

A novel helical Tilted Long-Period Grating (TLPG) was proposed and experimentally investigated. The sensor was fabricated by rotating optical fibers under the exposure of a CO2 laser. When the tilted angle of the TLPG is 50°, the asymmetric structure of the TLPG allows the sensor to recognize the direction of torsion. Compared with non-TLPG, the helical TLPG structure reduces the structural damage to the optical fiber. Furthermore, the torsion sensitivity of the clockwise and counterclockwise directions increased by 4.4 times and 1.5 times, respectively, compared to the non-TLPG configuration.