基于渐变折射率多模光纤的光纤法珀应变传感器

Abstract

By using a graded-index multimode fiber (GI-MMF) with a relatively flat index profile and high refractive index of the fiber core, a microextrinsic fiber-optic Fabry-Pérot interferometric (MEFPI) strain sensor is fabricated through chemical etching and fusion splicing.Higher reflectance of the microcavity is obtained due to the less-curved inner wall in the center of the fiber core after etching and higher index contrast between the GI-MMF core and air.The maximum reflection of the sensor is enhanced 12 dB than that obtained by etching of the Er-or B-doped fibers.High fringe contrast of 22 dB is obtained.The strain and temperature responses of the MEFPI sensors are investigated in this experiment.Good linearity and high sensitivity are achieved, with wavelength-strain and wavelength-temperature sensitivities of 7.82 pm/µε and 5.01 pm/ • C, respectively.