Strain gauge based on n-pairs of chirped fiber Bragg gratings

Abstract

Strain gauges based on fiber Bragg gratings are not only a well-developed field of research, but also gain a wide market due to their high sensitivity, response speed, immunity to electromagnetic radiation and flexible characteristics. In this work, we studied the strain gauge sensor based on n-pairs of chirped fiber Bragg gratings. These structures are inscribed at the same Bragg resonance wavelength within each individual pair. One grating is sensitive to applied load, the other is in the free position. Under mechanical impact, load-sensitive grating shifts to the region of long wavelengths. In this regard, the total reflection spectrum becomes wider and the reflected optical power increases. Bragg gratings are inscribed with reflection coefficients close to 100%. The experimental results to identify the dependencies between the applied mechanical stress and the reflected optical power are obtained. The proposed implementation of the sensor does not require spectral scanning of the gratings, which greatly simplifies its operation.