The Research Of Micro-radian Resolution Angle Sensor Based On Self-mixing Interferometry

Angle measurement based on laser self-mixing effect technology is a novel Angle measurement method with high precision and high resolution.The intensity of feedback light is changing with the variation of angle information in external feedback object,which modulate the laser output power.In view of the existing laser mixing angle measuring scheme,it all has limitation of narrow measuring range that caused by the feedback light cannot incident to the laser cavity when the angle of object changes a lot.Therefore,we proposed an angle measurement based on the laser self-mixing method in full circle range with high resolution and high precision,it not only solves the current problems of narrow measuring range,but also improved the resolution and precision of angle measurement.At the same time,we combine the laser self-mixing angle sensing system with the optical micro-cavity with miniaturization and high sensitivity and use the raman micro-cavity laser as the system light source to analyze and explore the angle sensing under the microstructure in detail.The innovation points of this paper including the following aspect:1.Based on the principle of laser self-mixing,this paper proposes a novel laser self-mixing angle measurement system,and establish the theoretical model on this scheme,which can realize angle measurement of micro-radian resolution in full circle range.2.On the basis of theoretical analysis,the experiment was carried out with the light source of Helium-Neon laser and feedback object of two plane mirrors with angle a.And make a comparison of experimental result and error under different vertex distances and different angle a between two mirrors in detail.3.Using the raman laser in micro-cavity as the laser source and combining the coupling principle of optical micro-cavity,we establish the theoretical model of angle sensing system of raman laser in micro-cavity.This system can realize the gain adjustment of the angle signal and is suitable for the angle measurement under the special circumstances of weak feedback signal.