Research On MOEMS Acceleration Sensing Method Based On Magneto-optical Effect

Acceleration sensing is an important inertial sensing method,which plays a vital role in military fields such as inertial guidance,aviation and navigation,as well as in civil fields such as vehicle control and wearable devices.In recent years,with the continuous development of micro-optical technology and the continuous maturity of MEMS(Micro-Electro-Mechanical System)technology,the MOEMS(Micro-Opto-Electro-Mechanical System)acceleration sensing method has emerged as the times require.MOEMS acceleration sensing not only retains the advantages of MEMS acceleration sensing,such as miniaturization,high reliability,and diversified structure,but also combines the characteristics of high sensitivity and high precision of optical sensing,and has become a hot spot in acceleration sensing research at home and abroad.One of the directions,but also creates the diversity of MOEMS acceleration sensing solutions.In this thesis,by studying the mechanism of the magneto-optical rotation effect,a coupled sensing model of the acceleration signal and the magneto-optical rotation angle is established,and an innovative MOEMS acceleration sensing method based on the magnetooptical rotation effect is proposed and verified.Through the design of the system index and scheme,the design modeling,simulation optimization and process preparation of the acceleration sensing structure based on the magneto-optical rotation effect were carried out,and the preparation of the acceleration sensing chip and the principle prototype was completed,and the structure was characterized.Test with effect.The main research contents of this thesis include the following aspects:(1)The mechanism of the magneto-optical rotation effect is studied,the conditions and influencing factors of the magneto-optical rotation angle are analyzed,and the coupled sensing model of the acceleration signal and the magneto-optical rotation effect is established: by detecting the magneto-optical rotation induced by the acceleration signal angle,so as to realize the sensing of acceleration information.Based on this,a mathematical solution model between the two was established,and a high-precision optical rotation angle detection mechanism based on elastic-optical modulation was studied.(2)The system index and scheme of the MOEMS acceleration sensing structure based on the magneto-optical rotation effect are designed,and the design of the acceleration sensing chip structure is carried out,and the parameter optimization and mechanical analysis of the structure are carried out combined with finite element simulation analysis.The reliability of the chip structure is verified.(3)The preparation and testing of the MOEMS acceleration sensing structure based on the magneto-optical effect is carried out.By designing the micro-nano process flow,the preparation of the acceleration sensor chip structure including the Nd Fe B film and the cantilever beammass structure was completed,and the prepared chip structure was characterized and tested.An optical rotation angle detection optical path based on elastic-optical modulation is built,and the Verdet constant of magneto-optical crystals is tested.By designing the shell,each module is fixed in the shell structure in the way of micro-assembly,and the preparation of the principle prototype is completed.A detection platform was built for the principle prototype,and the performance test of the sensing structure was completed.The test results showed that the sensitivity of the acceleration sensing structure was 314.3m V/g,the noise spectral density was8.3μg/√Hz,and the zero bias instability was 29.1μg.It exhibits high acceleration sensing performance.