Dynamic strain measurement system with fiber Bragg gratings and noise mitigation techniques

A low-cost fiber Bragg grating (FBG) vibrometer specifically suited for structural monitoring and aimed at the detection of low-amplitude vibrations is presented. The optical system exploits an intensity modulation principle of operation, while signal processing techniques are used to complement the transducer to improve the performances: a recursive least-squares adaptive filter improves the noise power mitigation by 14 dB, and an efficient spectral estimator permits operating spectral analysis even under high noise conditions. With these methods, a strain sensitivity of 5.6 n? has been achieved in the ?60 ?? range. Experimental assessment tests carried out in typical structural monitoring contexts have demonstrated that the developed sensor is well suited to measure mechanical perturbations of different structures.

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