An embedded pressure sensor based on polarization maintaining photonic crystal fiber

An embedded optical fiber pressure sensor was made by sandwiching a piece of polarization maintaining photonic crystal fiber (PM-PCF) between two polymer foils. The excess birefringence induced by the transverse pressure applied in different directions with respect to the birefringent axes of the PM-PCF was numerically calculated and the slow axis was identified to be the most sensitive direction. An experimental test was carried out by incorporating the embedded PM-PCF sensor in a Sagnac interferometer; the output interference fringes were found to shift linearly with the applied transverse pressure with a peak wavelength to pressure sensitivity of 1.764 nm MPa-1, which corresponds to a birefringence to pressure sensitivity of 2.476 × 10-6MPa-1.