Study Of Fiber Optic Fabry-Perot Interferometric Sensor Based On Hollow-Glass-Microsphere

With the increasing diversity and preparation technology,the application fields of optical fiber sensors have been expanding and miniaturized micro-structured optical fiber sensor have emerged.Micro-structured optical fiber Fabry-Perot(F-P)sensor is a research hotspot in the sensing field.Researchers have processed new types of fiberoptic F-P sensor by selecting new materials,improving the preparation process,and enhancing the performance of sensors.In this report,a hollow glass microsphere optical fiber F-P sensor is designed based on the principle of fiber-optic F-P interference,and the sensing performance of the prepared sensor is measured.The main research contents 1are as follows:(1)The research progress of micro-structure sensors based on multiple principles is introduced,and the sensing performance under various different structures and process conditions is compared and analyzed.According to the micro-structured fiberoptic sensor technology route of the current optimization of the preparation process and the reduction of production costs,the research direction has determined.(2)Based on the fiber-optic F-P sensor structure and interference theory,the effects of end-face reflectivity on the fineness of the interference spectrum and the shape of the interference spectrum at different end-face reflectivity is analyzed.A dualbeam F-P interference structure is processed.This report highlights the Fourier Transform and the Minimum Mean Square Error combination algorithm for demodulation.Finally,the temperature and pressure finite element simulation were performed on the hollow glass microsphere.(3)A hollow glass microsphere fiber-optic F-P sensing structure with simple fabrication and low cost was designed.Two fixed structures were introduced: doubleended fixed and single-ended fixed.(4)Experiments verified the temperature characteristics of the hollow glass microsphere fiber-optic F-P sensor.The temperature measurement range of the doubleended fixed F-P sensing probe is 30-40.5°C,and the temperature measured range of the single-ended fixed F-P sensing probe is 10-60°C.Experiments show that the hollow glass microsphere fiber-optic F-P sensor designed in this report has a high temperature sensitivity.The pressure characteristics of a single-ended fixed F-P sensing probe is experimentally analyzed,and the pressure measured range is 0.1-1MPa.The temperature and pressure test results of the single-ended F-P sensing probe are consistent with the simulation results.Finally,the fiber-optic F-P sensor was used for ultrasonic detection experiments,which provided ideas for the improvement of the structure of the fiber-optic F-P sensor and its application.In this report,a novel hollow glass microsphere fiber-optic F-P sensor is designed by improving the fabrication process of the micro-structured fiber-optic F-P sensor and selecting a new type of material.Compared with the reported microsphere fiber-optic F-P sensor,the sensor of this structure has the advantages of simple manufacturing process,low cost and high temperature sensitivity,and has very important scientific significance and application prospects.