Research on an identical weak FBGs array sensor towards large-area flexible pressure sensing

To simultaneously achieve the feature of high sensitivity, high precision and large-area in tactile sensing, a hollowed-out quadrangular prism structure flexible pressure sensor based on an identical weak fiber Bragg gratings (IWFBGs) array is proposed. The flexible packaging structure featuring a hollowed-out quadrangular prism was designed by finite element simulation, with the IWFBGs array embedded in the flexible silicone rubber to prepare the sensor. The pressure-induced reflection spectrum shifts of the IWFBGs array were analyzed using optical frequency domain reflectometry (OFDR) technology, and quantitative relationships between wavelength shifts and pressure were established through linear regression analysis. Experimental results demonstrated that the proposed sensor exhibits a sensitivity of up to 88.15 pm/N, with a low sensitivity error of ± 0.91 pm/N and a high-resolution pressure detection capability of 0.1 N. Additionally, by constructing a dynamic dual-parameter decoupling matrix, temperature–pressure crosstalk was effectively eliminated, reducing pressure demodulation errors by 99.17 % and significantly enhancing sensor reliability under temperature variations. The proposed sensor leverages the inherent multiplexing advantages of IWFBGs, demonstrating a novel pathway for deploying high sensitivity, high-precision, and large-area all-fiber tactile sensing networks in wearable bionic skins and adaptive intelligent surfaces.