A S-Shaped Long-Period Fiber Grating with Ultra-High Strain Sensitivity

Abstract A S-shaped long-period fiber grating (SLPFG) is presented in this paper as a new type of strain sensor with ultra-high strain sensitivity. The sensor is fabricated by using the CO2-laser-polished method. It is illustrated by experiments that the WLFPG has structural stability and repeatability. The strain sensitivity of the proposed sensor reaches 29.3 pm/μe in the range of 0∼1000 μe, and the temperature sensitivity is 76.3 pm/°C in the range of 30∼170 °C. Compared to other CO2-laser-induced long-period fiber gratings (CO2-LPFGs), the strain sensitivity of the SLPFG is nearly ten times higher.