Temperature-insensitive 2D Tilt Sensor with Two Chirped Fiber Bragg Gratings

A novel temperature-insensitive tilt sensor is proposed by embedding two chirped fiber Bragg gratings (CFBGs) into a cylindrical cantilever-based pendulum in two orthogonal planes. Due to the tilt-induced nonuniform strain field applied along the length of the CFBGs, their bandwidths of reflection spectra vary with the applied tilt angle. By measuring the reflected optical powers of the two CFBGs illuminated by a flattened broadband light source, temperature-insensitive measurement of both inclination angle and direction in two dimensions can be realized. Theoretical calculations and preliminary experimental results verified the feasibility of the proposed sensor design. The measurement is in real-time manner and the sensor is cost-efficient because it is an intensity-modulated sensor.