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。

Based on the theory of laser self-mixing interference, a new type of distance measuring method using two feedback laser self-mixing interference is presented. The triangular wave current is used to modulate the semiconductor laser, and a feedback self-mixing interference signal is obtained. Through the analysis of the signal, it is known that when the semiconductor laser is modulated, it will produce a series of mode hopping. The number of mode jumps is proportional to the absolute distance, and the absolute distance can be obtained by calculating the number of the mode hopping in a triangle wave current modulation period. Based on the concept of multi laser self-mixing, the new type of distance measurement method is proposed. A distance measurement system is established, and the experimental verification is carried out. The experimental results show that the precision of measurement is improved obviously due to the increase of the resolution accuracy of the step size.