Fiber-Optic Fabry–Perot Sensor for Simultaneous Measurement of Tilt Angle and Vibration Acceleration

A fiber-optic Fabry-Perot (F-P) sensor, based on a pendulum structure, for simultaneous measurement of tilt angle and vibration acceleration was proposed, which also has a high-tilt angle resolution. The real-time cavity lengths are absolutely measured using a fast demodulation algorithm. The tilt angle is estimated from the mean value of the real-time cavity lengths while the vibration acceleration derives from the alternating quantity of them. A series of experiments are conducted using a micro-tilt platform and a vibration table to simulate tilt angle change and the vibration perturbation, respectively. The experimental results show a tilt angle resolution of 0.023" in the measurement range from -2.8° to 2.6°. Meanwhile, the vibration acceleration results are obtained by using a spectral analysis to the alternating quantity and basing on a non-linear fitting curve of the frequency response of the acceleration sensibility, within the frequency range of 0~180 Hz.