Fabry–Perot Curvature Sensor With Cavities Based on UV-Curable Resins: Design, Analysis, and Data Integration Approach

This paper presents the development of a Fabry–Perot interferometer (FPI) for curvature sensing. Ultraviolet (UV)-curable resins are used in the FPI cavity. In this case, two configurations for the FPI curvature sensor are tested, one with the UV-curable resin in between two standard single mode fibers (SMFs), namely SMF-FPI configuration and the other using a SMF and a perfluorinated polymer optical fiber (POF) with the resin between them, referred as the POF-FPI configuration. Analytical simulations were performed for both configurations in order to evaluate FPIs’ wavelength shift and power variation as function of the bending angle, where such analyses are, then, confirmed by the experimental results with higher sensitivity as function of the wavelength shift for the POF-FPI and, higher sensitivity of SMF-FPI for the optical power variation. Thereafter, a data fusion for the FPI’s wavelength shift and optical power variation was proposed using the Kalman filter, where the angle response after the data fusion is compared with the ones using only wavelength shift or optical power variation for both FPI configurations. The results show error decrease in all analyzed cases with up to sixfold reduction of the root mean squared error (RMSE).