Temperature-insensitive fiber-Bragg-grating-based vibration sensor

In this paper, we propose a simple optical fiber sensor for the measurement of vibration. The sensor consists of two fiber Bragg gratings, which have partially overlapped reflection spectra and are mounted on the opposite sides of a flexible beam. With this setting, the light intensity reflected by the gratings is modulated by the vibration of the beam and adverse thermal effects can be largely eliminated. Experimental results are presented to demonstrate the feasibility of the sensor.