Highly sensitive and temperature-compensated fiber bending sensing based on directional resonance coupling in photonic crystal fibers

Abstract A highly sensitive bending sensor with temperature-compensation based on magnetic fluids (MF) infiltrated photonic crystal fiber (PCF) is presented. Specific cladding air-holes are filled with MF material to form defective channels and introduce new degrees of freedom for fiber sensing. The structure designed in such way can achieve simultaneous measurement of bend-curvature and bend-direction with temperature compensation. The bending sensitivity can reach to −6.544 nm/m −1 with a high linearity within the range of curvature from −10 m −1 to 10 m −1 . The proposed two-dimensional (2D) bending vector sensor cannot only improve the sensing precision and measurement range, but also reduce the metrical difficulty and simplify the process.