| With the ongoing advancement of sensing technology,for their advantages of compact size,lightweight,high sensitivity,corrosion resistance and so on,fiber-optic sensors have been widely employed in measuring temperature,pressure,strain/stress etc.in a various areas.Fiber-optic sensor interrogator is an important part of fiber-optic sensing technology,which has important scientific research value and wide application prospects.Aiming at the demand of temperature and pressure dual-parameter synchronous measurement,Based on the Fizeau interferencing principle,this thesis designs a white light interferometer space cross-correlation fiber-optic F-P cavity interrogator,which utilizes a double optical wedge structure,which designed to precisely measure both temperature and pressure.The feasibility,reliability and stability of the interrogator are verified by simulation and experiment.The main contents of this thesis are summarized as follows:Firstly,an examination of the composite fiber-optic F-P sensor’s working principle and interrogation techniques is conducted,with a comparison of the benefits and drawbacks of different interrogation techniques.Based on the principle of Fizeau interferometer,a white light interferometer space cross-correlation fiber-optic F-P cavity interrogator is designed.The interrogation principle of the white light interferometer space cross-correlation fiber-optic F-P cavity interrogation instrument is theoretically derived and introduced,and the feasibility of the interrogation technology is verified by simulation.The optical path of the interrogator is built.Then,the circuit and software for signal acquisition and processing are designed,the interrogation system is based on STM32F407.Linear CCD detects the optical signal,which transmitted to the chip via ADC08060.Finally,the data processing software and interrogation algorithm are designed to interrogate the pertinent interference signal.The STM32 main control module,A/D conversion,CCD photoelectric detection and serial communication are all components of the designed circuit.The interrogation algorithms include Chebyshev bandpass filtering and Gaussian function fitting.Finally,verify the reliability,feasibility,and stability of a white light interferometer space cross-correlation fiber-optic F-P cavity interrogation system,an experimental platform has been constructed at last.Calibrate the entire interrogation system,the experiment gauged the combined fiber-optic F-P sensor under varying temperatures and pressures to ascertain the correlation between the pixel that corresponds to the peak of the pertinent interference signal and the temperature and pressure,and performed the reproducibility experiments on the interrogation system.The findings demonstrate that the sensitivity of pressure and temperature are-23.396 /MPa and-0.213 /℃ respectively.The maximum discrepancy between the interrogated pressure and the standard pressure is 0.017 MPa,and the greatest discrepancy between the measured temperature and the standard temperature is 0.533 ℃.The temperature range is 20-300 ℃,and the pressure range is 0.1-3 MPa,thus enabling real-time dual-parameter measurement of temperature and pressure. |
