Research On The Infulence Of Corrugated Structure On The Performance Of Diaphragm-based EFPI Fiber Acoustic Sensor

Acoustic sensor has a wide range of applications in the military,medical,agriculture,industry,life and other aspects.Diaphragm-based EFPI fiber acoustic sensor has been paid attention to because of possessing the advantage of miniature structure,simple manufacture,low cost,rapid response and insensitivity to temperature.Traditional diaphragm structure,with a simple structure,easy processing advantages.But there are shortcomings such as small dynamic range and limited performance space.In this paper,we mainly research on the MEMS processing method of corrugated structure in the miniature diaphragm-based EFPI fiber acoustic sensor and the influence of corrugated structure on the performance of the sensor.In this paper,the deformation theory of corrugated diaphragm under different initial stress conditions is analyzed in detail.According to the theoretical analysis results,under different initial stress conditions,the corrugation depth is the main parameter affecting the mechanical properties of the diaphragm.For the corrugated diaphragm without initial stress,the mechanical sensitivity decreases with the increase of the corrugation depth.For the corrugated diaphragm with initial stress,the mechanical sensitivity increases first and then decreases with the increase of the corrugation depth,then tends to be stable.The processing method of transferring the corrugated structure to the metal diaphragm and PET diaphragm by means of commonly used photolithography technology,reactive ion etching technique,sputtering technique and thermal nanoimprint technology is proposed.Compared with the traditional method of processing corrugated structure,the MEMS processing technology is simple,short production period,the material is saved and the corrugated structure parameters are controlled flexibly.The corrugated diaphragm EFPI fiber acoustic sensor was obtained by packaging the metal diaphragm and PET diaphragm with different corrugation depth.The strength demodulation system was built and the acoustic performance of the corrugated diaphragm-based EFPI fiber acoustic sensors are tested in air and water.The influence of the corrugated structure on the performance of the sensor is analyzed.The test results show that the corrugation structure improves the performance of the diaphragm-based EFPI fiber acoustic sensor.