Study On Fiber Bragg Grating Lfuid Refractive Index Gradient Sensor

With the rapid development of biological science, biomedical disciplines,corresponding to biochemical information technology requirements are constantly improve.Fiber Bragg grating biochemical sensor with its small size, strong anti-interference, highsensitivity, the advantages of good real-time performance, has become the optical fibersensing technology and other subjects crossover study of one of the hot spots. Biochemicalsensors the basic principle of fiber Bragg grating are external medium by measuring thechange of refractive index (SRI), indirect estimation value of the parameter beingmeasured. So, if can realize measurement of SRI, can obtain more information related tothe biochemical reaction process.This paper deeply studies the optical fiber Bragg grating reflective spectrum changingwith SRI principles and general rules. And on the basis of the theory, we obtain the optimaldesign scheme of the gradient sensor parameters, design and produce a "RI gradient basedon FBG sensor, the sensor of the cladding is fully corrosion and high refractive indexsensitivity, and finally applied to the sucrose solution were measured. This topic mainresearch content is as follows:(1) The use of the constructed "modified transmission method", the main structureparameters of different several FBG in RI linear distribution function of reflectionspectrum of liquid medium environment theory, simulation and analysis of main structureparameters of sensor on its reflection spectrum.(2) Design and build in non-uniform micro pipe liquid medium experiment system,through the experimental research on FBG is linear distribution function in the RI of thereflection spectrum of liquid medium environment, to verify and correct theory of researchcontents:(1) the simulation conclusion.(3) Based on theoretical simulation and experimental results, the FBG reflectionspectrum characteristics (maximum and minimum differential micro resonant peakwavelength, spectral intensity and spectral bandwidth, etc.) and the non-uniform RIdistribution function of characteristic parameters of liquid medium (along the axialgradient of FBG, RI RI difference on opposite sides of the FBG, etc.) the relationshipbetween the qualitative and quantitative analysis.(4) Integrated the above research results, build based on the theory of FBG fluid RI gradient measurement model and its corresponding sensor parameters optimal designscheme.This topic can be for a variety of biochemical reactions related to the refractive indexof medium in the process of study provide strong theoretical support, and to promote thebiochemical sensors, optical fiber grating non-uniform liquid under the conditions ofdevelopment, provide a reference basis for optical fiber sensor in the direction of thehigher sensitivity of the gradient measurement is of certain guiding role.