Research Of Fiber Optic Acoustic And Temperature Dual-Parameter Sensing Based On Hybrid Fabry-Perot Microcavity

Fiber optic sensors based on Fabry-Perot microcavity have the advantages of small size,light weight,no electromagnetic interference,and have broad development prospects in the aerospace field.Acoustic and temperature are two important parameters to characterize the state of the aeroengine.Acoustic localization based on the sensor array can realize acoustic information vector detection further.Based on the above requirements,the paper studies the fiber optic acoustic and temperature dual-parameter sensor based on hybrid Fabry-Perot microcavity,analyzes the interference theories and demodulation methods of the sensor and conducts the acoustic and temperature doubleparameter test experiments.On this basis,fiber optic Fabry-Perot sensing technology combined with array acoustic localization technology to conduct fiber optic acoustic localization sensing research.The specific work completed in this paper is as follows:1.Based on the fiber optic Fabry-Perot interference theory,a fiber optic acoustic and temperature dual-parameter sensor based on hybrid Fabry-Perot microcavity is studied.The hybrid Fabry-Perot microcavity is realized by a silicon-glass-silicon threelayer structure in which an air microcavity is used for measuring acoustic,and a silicon microcavity is used for measuring temperature.2.The sensitivity analysis of the fiber optic acoustic and temperature dualparameter sensor based on hybrid Fabry-Perot microcavity is performed.The demodulation methods are studied based on the interference spectrum of hybrid FabryPerot microcavity and the characteristics of the measured parameters.The acoustic information is demodulated by the intensity based on a single-frequency laser,and the temperature information is demodulated by the cavity length based on broad spectral analysis.3.An experimental system for acoustic and temperature dual-parameter sensing is set up and experimental research is carried out.The experimental results show that the sensor can effectively recover the acoustic signal and temperature information.The acoustic sensitivity of the sensor is 4.65 m V/Pa at 21 k Hz,and the temperature sensitivity is 123.10 nm /°C in the range of 20°C?120°C.The experiment verifies the omnidirectional characteristics of the sensor with a signal-to-noise ratio(SNR)of 70 d B.4.The fiber optic acoustic localization technology based on sensor array is studied.The acoustic localization algorithm based on the time delay estimation is analyzed.The factors affecting the positioning accuracy are analyzed.And the array acoustic localization experimental system is set up.The experimental results show that the fiber optic acoustic and temperature dual-parameter sensor can realize acoustic localization.