Research Of The Theory On Laser Diode Feedback Interference And Its Application In The Measurement Of The Surface Profile

Advanced laser interference measurement technique that is gradually maturinghas widely applied in many fields such as industry, medical treatment, communicationetc. particularly in displacement, vibration, and surface profile measure in industryproduce. It has become important measure means for its high accuracy and no contactand scatheless detection. While this new technique in actual application has always adisadvantage of the exaction to its use environment. For example, measuring accuracyis affected by environment vibration;temperature change etc. and this limited itsextensive application in actual production. How to low down the demand toenvironment is the important task in laser interference measurement technique and itsapplication is very useful.First, general laser feedback interference was analyzed theoretically andstimulating calculated in this dissertation. Strong/weak laser feedback interferenceexperiments were made in our LD practice system. The interference pattern andoutput signal were taken. As one innovation of this thesis, we have put forward ourown theoretical model for multiple external cavities, and applied this model in laterexperiment. It got proved indirect.Second, on the base of analyzing laser diode feedback interference fringe-lockingphenomenon appeared in recently years, we made deeply study on both theory andexperiment for LD feedback interferometer working principle, and proposed atheoretical model of a four-mirror F-P equivalent cavity for LD feedbackinterferometer, with analyzing, deducted the lasing condition and fringe-lockingmechanism of laser diode feedback interference,and led to another new innovation.We calculated and concluded the dependence of lasing wavelength on the change ofthe optical path difference of the interferometer. The observation experiment of laserdiode feedback interference fringe-locking was made in Twyman–Greeninterferometer, the experimental results agreed well with the theoretical calculations.This is experiment innovation.At last,brief introduced surface profile parameters and optical measure methods,especially laser interference measure method. The experiment of fine surface profilemeasure and basic anti-disturb were made on LD feedback interference experimentsystem. This is also another new innovation on the experiment. The practical newmethod was put forward to reduce reliance on the environment exaction for LDfeedback interference measure technique.