.Study of the characteristics of concentration sensing based on FBG Fabry-Perot cavity[J].Optoelectronics Letters,2009,5(2):138-142 Study of the characteristics of concentration sensing based on FBG Fabry-Perot cavity 吴飞  朱国芳  陈曦 College of Electrical Engineering, Yanshan University, Qinhuangdao 066004, China ? Abstract:       Fiber Bragg grating Fabry-Perot (FBG F-P) cavity is used as the sensing model to measure the refractive index of the liquid solution. The cladding of the fiber, which is used as the F-P cavity, is etched by HF solution to enhance the sensitivity to the external refractive index. The experimental results show that with the concentration change of the external solution, the effective refractive index of etched fiber will change, thus the spectra of FBG F-P cavity will appear a spilt point. The relationship between the wavelength at spilt point and the effective refractive index of etched fiber is approximately linear, and also periodical. The sensing model is theoretically analyzed based on transfer matrix method, and the corresponding mathematic model is established. Hits: 3711 Download times: 196 View Full Text    Download reader