A Strain Sensor Based on Core-Distortion Long-Period Fiber Grating

A compact strain sensor based on core-distortion long-period fiber grating (CD-LPFG) is proposed and investigated. The manufacturing of the sensor includes pre-twisted CO2 laser polishing and hydrogen-oxygen flame heating method, which leads to the characteristic of periodic core-distortion of the fiber structure. Within the strain measurement range of 0- $350~\mu \varepsilon $ , the proposed sensor exhibits a high strain sensitivity of −41 pm/ $\mu \varepsilon $ . Additionally, within the temperature measurement range of 25-100 °C, the sensor demonstrates a temperature sensitivity of 56 pm/°C. Furthermore, the sensor has a compact structure with a length of only 5mm, making it highly suitable for precise measurement applications in limited spaces.