Stabilized Interrogation and Multiplexing Techniques for Fiber Bragg Grating Vibration Sensors

We demonstrated a simple interrogation system for multiplexed fiber Bragg grating sensors with high frequency range. A tunable Fabry-Perot filter with narrow free spectral range (FSR) was used to simplify the multiplexing demodulator for FBG vibration sensors. A stabilization controlling unit was also developed for the maintenance of maximum sensitivity of the sensors. In order to verify the performance of the stabilization control unit, we measured the sensitivity of the FBG sensor by changing a environmental temperature, and the system showed an average sensitivity of 2.5 / RMS n Hz ε for a stabilization controlled case. Finally, multi-points vibration tests using in-line FBG sensors were conducted to validate the multiplexing performance of the FBG system.