线形腔光纤激光器的光反馈效应研究

The optical feedback effect on the fiber linear laser

提出了一种基于线形腔光纤激光器结构的光学反馈系统,对系统输出功率变化表达式进行了推导,建立模型分析了光反馈对系统的影响,得出其与激光自混合干涉具有相同的相位灵敏度.实验中首先对系统进行了信号观测,同时改变实验条件,对不同参数的影响进行了讨论,实验结果与模拟分析相一致.结果表明:线形腔光纤激光器光反馈系统的输出条纹变化对应着待测物半个波长的位移;条纹不同的倾斜方向可实现对移动方向的辨别;通过适当调节反馈腔腔长与目标靶反射率可优化系统反馈信号的灵敏度.根据以上特性,该系统可应用于光学测量领域,例如位移、距离、速度测量等.

In this paper,an optical feedback system based on fiber linear lasers is presented. The effects of optical feedback could be equivalent to the variation of laser cavity loss,and the output expression of the optical feedback system is deduced. A model is built to analyze the feedback influence on the system. The internal optical feedback effect on fiber linear lasers is similar to self-mixing interference,and the former has same phase sensitivity with the later. The influence from different parameters is analyzed in simulation. The system output is detected in experiment,and the influence of different parameters is also discussed by changing the experimental conditions. The experimental results show a good agreement with the simulated results. The conclusion can be summarized as follows：One fringe shifting of the system output corresponds to a target displacement of λ/2; the different inclination refers to different movement direction; the better sensitivity of optical feedback system can be obtained by choosing appropriate feedback cavity length and target reflectivity. Consequently,this system can be applied to optical survey,such as displacement,distance,velocity measurement,etc.