Multigray Linear Acousto-optic Modulator And Its Application In Optical Heterodyne Interference

With the rapid development of lasers and the continuous development of high-quality acoustooptic crystal materials,acoustooptic devices based on Bragg diffraction have been widely used in optical heterodyne interferometry and optical communication.In optical heterodyne interferometry,due to the diversity of the measured objects,its reflectance and roughness of the surface will have a great impact on the measurement of micro-displacement and micro-vibration,so it is very necessary to study the optical path of optical heterodyne interferometry and the driving power of the acoutic-optical modulator that determines the quality of the acoutic-optical devices.Aiming at the influence of surface roughness and reflectance on the optical heterodyne interferometry system,the optical system is improved,and the design of the optical path measurement system is realized.According to the characteristics and functions of each optical element,the main sources of nonlinear errors in the system are analyzed,the specific errors are derived mathematically,and the results are analyzed by simulation.In the process of actual measurement,according to the need of heterodyne interferometry system,design a kind of gray linear acousto-optic modulator driver source,using the digital potentiometer DS3902 as the core of constant current source circuit,the characteristics of the acousto-optic modulator diffraction intensity were tested,the experiment results show that the diffraction intensity grey value and digital voltage into a nonlinear relationship,using linear compensation technique to modulation of constant current source circuit,after makes the modulation of diffraction intensity with the grey scale linear change,linear correlation coefficient can reach 99.91%,increased by 1.15% compared to that before compensation.Through the static and dynamic experiments of multigray heterodyne interferometry system,it is proved that the driving power of multigray linear acoustoopticmodulator can improve the measuring performance of the system and has superior testing performance.