Micro-fiber-based FBG sensor for simultaneous measurement of vibration and temperature

We propose and experimentally demonstrate an integrated in-line micro-fiber sensor based on fiber Bragg gratings to measure simultaneously the vibration and temperature information for state estimation of cable-stayed bridges. The micro vibration structure with micro beam and mass block is integrated to a normal single mode fiber by a special chemical etching method. The results reveal that both of the gratings exhibit similar temperature sensitivities (8.55 and 8.09 pm/° C) but markedly different sensitivities for ultra-low frequency vibration. This kind of the sensing structure is a new type of sensor for simultaneous measurement of temperature and ultra-low frequency vibration particularly for monitoring the large structure health. © 1989-2012 IEEE.