Research On Tilted Fiber Grating Characteristics And Sensing Technology

Tilted Fiber Bragg Grating(TFBG)is a type of fiber grating with a special structure,which has important research value due to its special coupling mode and excellent optical performance.TFBG unique coupling method makes it not only extremely sensitive to the surrounding environmental parameters,but also can solve the problem of fiber grating temperature and stress cross-sensitivity.Therefore,in the field of sensing and other fields,TFBG is increasingly valued by researchers.In this paper,the theoretical characteristics,spectral characteristics and sensing characteristics of TFBG are studied.Based on TFBG,a cascaded TFBG is proposed.The main contents are as follows:1.A brief history,classification and application of fiber grating are introduced.On the basis of fiber grating,a brief history of TFBG development,engraving technology and its application in various fields are introduced.2.This paper introduces the theoretical research progress of TFBG,studies the basic structure of TFBG and its coupling mode theory,and analyzes the coupling mode of each mode in detail by using coupling mode theory.3.On the basis of TFBG theory,the principle and analysis method of cascaded TFBG are studied,and the theory of cascaded TFBG is deduced by transfer matrix method.The spectral characteristics of cascaded TFBG are studied in detail.The spectral characteristics of cascaded TFBG under different structural parameters are analyzed in detail.The structural parameters include the number of cascaded gratings,the grating tilt angle,grating spacing,grating period,grating length,core radius and refractive index,cladding radius and refractive index.Finally,the mutual compensation between different parameters is analyzed.The research results are of guiding significance for the design and optimization of cascaded inclined fiber gratings.4.This paper investigates the sensing characteristics of TFBG and cascaded TFBG,including temperature sensing and stress sensing.The basic principle of TFBG temperature sensing and stress sensing is analyzed in detail,and various factors affecting temperature sensing and stress sensing are analyzed.Using Optigrating and Matlab software to study TFBG and cascaded TFBG.The results show that compared with TFBG,the cascaded TFBG not only has more abundant spectral characteristics,but also the sensitivity of cascaded TFBG temperaturesensing is higher than the sensitivity of TFBG temperature sensing,which improves the sensitivity of temperature sensing.In addition,the sensitivity of cascaded TFBG stress sensing is slightly higher than the sensitivity of TFBG stress sensing.It has certain reference value for the practical application of TFBG and cascaded TFBG,which provides the theoretical basis for the subsequent application in the fields of light sensing and so on,which has very important research significance.