Fiber Strain Sensor Based on Incline Plane-Shaped Long Period Fiber Grating Induced by CO 2 Laser Polishing

In this paper, we propose the CO2 laser polishing method to prepare a novel type of incline plane-shaped long period fiber grating (IPS-LPFG) for strain measurement. This structure is achieved by periodic incline plane-shaped structures polished on single mode fiber. The incline plane-shaped structure introduced asymmetric thickness of the side plane, which enhances the strain sensitivity of the sensor effectively. Experimental results illustrate that the compact strain sensor with a length of 5 mm achieves a high strain sensitivity of 15 pm/ $\mu \varepsilon $ at the range of 0- $900~\mu \varepsilon $ , and the temperature sensitivity of it is 54.5 pm/°C. Moreover, the proposed strain sensor has good mechanical properties and high repeatability, which demonstrates the potential in optical fiber sensing.