Simultaneous Measurement of Tilt Angle and Temperature With Pendulum-Based Fiber Bragg Grating Sensor

A fiber optic tilt senor for simultaneous measurement of 2-D tilt angle and temperature is proposed and demonstrated experimentally. The sensing head consists of two fiber Bragg gratings (FBGs) attached on a specially designed columnar pendulum. Reflection peaks of the FBGs split and resonant wavelengths shift with tilt and temperature variations. A maximum tilt angle sensitivity of 0.074 nm/degrees, accuracy of 0.18 degrees, and temperature sensitivity of 0.021 nm/degrees C have been achieved within the tilt angle range of 0 degrees-40 degrees.