在基于激光自混合干涉的理论上,提出了一种利用二次反馈激光自混合干涉的新型测距方法。利用三角波电流对半导体激光器进行调制,得到一次反馈自混合干涉信号。通过对信号分析可知,当半导体激光器被调制后,会产生一系列的模跳,模跳的数量与绝对距离成正比。通过计算在一个三角波电流调制周期内模跳的数量,就可以求出绝对距离。利用多重激光自混合的概念,提出该种新型测距方法。建立了距离测量系统,进行了实验验证。实验结果表明:由于步长分辨率精度的提高,测距精度明显提高。 In the theory of laser self-mixing interference, a novel distance measurement method using self-mixing interference of secondary feedback laser is proposed. The triangular wave current is used to modulate the semiconductor laser to obtain a feedback self-mixing interference signal. Through the signal analysis shows that when the semiconductor laser is modulated, it will produce a series of mode hopping, mode hopping the number is proportional to the absolute distance. The absolute distance can be calculated by counting the number of mode hops in a triangular wave current modulation period. Utilizing the concept of multiple laser self-mixing, this new type of distance measurement method is proposed. A distance measurement system was established and verified by experiments. Experimental results show that the accuracy of ranging is obviously improved due to the improvement of the resolution of the step size.