Fiber grating pressure sensor with enhanced sensitivity using a novel packaging polymer

A packaging polymer enhanced sensitivity of fiber Bragg grating pressure sensor was synthesized from hydroxyl terminated polypropylene oxide oligomers, toluene diisocyanate (TDI), 1,4 Butandiol as chain extender, foaming agent and foam stabilizer. The packaging polymer is a kind of microcellular elastic rubber, which is compressible. The testing results show that of Young´s modulus, Poisson´ ratio of the packaging polymer are 7.6 × 10⁷ N-m^-2 and 0.42 respectively. The theoretical pressure sensitivity coefficient of fiber Bragg grating packaged with the polymer jacket is -1.73 × 10^-3/MPa, which are 896 times of that of the bare fiber Bragg grating (-1.93 × 10^-6/MPa).