适度反馈机制下非准直外腔二重反馈自混合干涉

为了研究多重反馈对半导体激光器自混合信号的影响,运用三腔镜模型分析了多重反馈和非准直倍频现象,并进行了仿真分析和实验验证。通过仿真发现,第2重反馈相对于第1重反馈的相对强度η较大时能明显分辨出二重反馈,利用信号微分能区分出二重反馈信号,实现系统分辨率达到λ/4,二重反馈之间非准直相位差会影响干涉信号波形。实验验证了外腔反射镜非准直抑制第1重反馈利用二重反馈实现非准直干涉条纹倍频现象,实验结果与仿真分析相符。该结论将有利于提高系统分辨率和判断外腔是否准直。

Double feedback self-mixing interference under moderate feedback of misalignment cavity

In order to study the influence of the multiple feedback on the self-mixing interference in laser diodes, double feedback effect and double frequency fringes phenomena were analyzed based on the three-mirror F-P model. After simulation, it is found that when the relative intensity η of the second trip light to the first is big enough, the image of interference can be recognized, and the two interferential signals of two trips can be distinguished by differential coefficients. The sensitivity of system can reach the value of λ/4. The phase differences affect the interference pattern. Experimental results are in good agreement with the simulation results. Experiments also validate the double frequency fringes phenomena, caused by the misalignment external reflector, could coupling the second trip light into laser without first trip. These obtained conclusions are helpful for improving the sensitivity of the system and judging whether the external cavity is alignment.