Filter-based interrogation of fiber Bragg grating sensors

We present a compact and robust interrogation device for the read out of fiber Bragg grating sensors. The core system consists of a dielectric thin film filter with a lateral spectral transmission gradient and a photo diode array. This allows a high resolution detection of the Bragg wavelength shift by means of a centroid measurement. We first show the functionality of the system with a temperature measurement on a fiber Bragg grating. We achieved a temperature resolution of 0.2 K and an accuracy of ± 2 K, which correspond to a spectral resolution of 1 pm and an accuracy of ± 11 pm. On the basis of these results, we developed a specially adapted high sensitivity electronics and a robust packaging for the applications on pipeline structures.