Research on the Refractive-Index Gradient Sensor Based on Gaussian Apodized Fiber Bragg Grating under Uneven Medium

Based on the fiber waveguide theory and the transfer matrix method,Research on the reflection spectrum of Gaussian apodized FBG which cladding were completely corroded under uneven medium.During the stimulation process,consider high refractive-index(1.43-1.45) area and low refravtive area(1.33-1.36) respectively.At the same time,suppose the uneven SRI in different linear function distributions.The stimulation result shows the Gussian apodized FBG’s spectrum bandwidth,spectrum intensity depends on the SRI along the grating axial linear distribution gradient.As SRI gradient increases,the gradient sensitivity of high refractive index area and low refractive index area are nm.mm/riu and nm.mm/riu respectively.The results have a definite significance of Gaussian apodized FBG for sensing technology used in biochemical of uneven medium measurement.