Technology Research Of Refractive Index Sensor Based Ongrating Fiber

Refractive index sensor is one application of grating fiber, it has many advantages, such as simplified structure, flexible design, anti electromagnetic interference and etc, at the same time, how to improve the RI sensitivity and eliminate the cross sensitivity problem are always the hot spots in this field. Based on our research group’s experiences in fiber grating, we have been making research in refractive index sensors of single-mode fiber cascaded LPG and FBG, also in Bragg grating refractive index sensor of liquid-filling PCF, and we specially made one simulation on the refractive index rate of micro nano fiber FBG sensor. This specific research work of this paper summarized as follows:Firstly, the paper introduces the development and classification of grating fiber, and respectively introduces FBG and LPG sensing application schemes. Exploring the engraving grating parameters and setting the sensing measurement experiment scheme are based on the system analysis in coupled-mode theory, transfer matrix method and evanescent field theory.Secondly, the paper analyses the recently hot spot of micro nano fiber sensor technology and the reason of its ultra high refractive index sensitivity, then carries out the theoretical simulation of micro nano Bragg grating refractive index rate and analyses its response disciplinarian.Thirdly, the paper makes systemic study in the theory of cascaded LPG and FBG fiber grating, also the method of engraving and measuring, and finds the relationship between the engraved parameter and the resonant peak reflectivity by repeating experiment, and finds the response disciplinarian of resonant peak’s wavelength with temperature and refractive index.Finally, the paper studies and simulates the liquid-filling PCF Bragg gratings refractive index sensor’s wavelength change trend between different orders, and calculates out the RIU under different orders and movements of liquid, and successfully welds the single-mode optical fiber and the photonic crystal fiber and engraving the FBG on photonic crystal fiber, and finish the refractive index sensing experiment with the engraving finished product through setting up the experimental measurement system, As a result, the experiment date fits well with the simulate data.