Study on Refractive Index and Concentration Sensor Based on Long-Period Fiber Grating

Based on the simplified three-layered model,long-period fiber grating's sensitivity to the surrounding refractive index and concentration is analyzed with the couple-mode theory. Computer was use to simulate and calculate the numerical value of the grating, and to achieve the relation between the resonance wavelength of LPG's transmittance and the surrounding refractive index and concentration. The experimental results fit the computer simulation results well.