Enhanced laser self-mixing Doppler velocity measurement with pre-feedback mirror

On the basis of conventional measurement, a novel enhanced laser self-mixing Doppler velocimetry is proposed in this paper, with a pre-feedback structure added to enhance the signals. The improved velocimetry is applicable to the measure of the velocity when the feedback light is weak. Through the exploration of the theoretical model and the performance of experiments, the study results show that the proposed method has a significant signal enhancement effect, with experimental measurement relative errors being less than 0.9%.