Temperature-Insensitive Real-Time Inclinometer Based on an Etched Fiber Bragg Grating

We propose and experimentally demonstrate a compact temperature-insensitive inclinometer, which is constructed by connecting a chemically etched fiber Bragg grating to a hollow-core fiber filled with tin. The optical power reflected from the grating is linearly proportional to the inclination angle of the grating and can provide a real-time measure of the inclination angle. Our experimental sensor can measure the inclination angle from 0 $^{\circ}$ to 20 $^{\circ}$ with an uncertainty of ${\pm}{0.35}^{\circ}$ and negligible temperature interference.