Mechanical rotation and bending sensing by chiral long-period grating based on an axis-offset rotating optical fiber

A chiral long-period fiber grating (CLPFG) was fabricated by rotating the standard single mode fiber that was fixed on two fiber holders with an axis-offset. We investigated the performance of CLPFGs by sensing the mechanical twist, bending, and liquid refractive index experimentally. A wide twist sensing range of ±720° and 26.7 nm wavelength tuning range were achieved. Compared with tapered long-period fiber grating, the bending sensitivity of CLPFG is 5 times higher. Considering the simple and flexible fabrication process and low cost, this CLPFG may offer a simple and alternative choice for sensing mechanical deformation in industrial applications.