Damping Microvibration Measurement Using Laser Diode Self-Mixing Interference

Based on the study of laser diode self-mixing interference effects, a simple damping microvibration measuring method that can accurately obtain the damping factor is presented. The damping factor is solved by recording the period and counting the fringe number of the self-mixing signal. The damping factor of 0.0483 s^-1 with a standard deviation of 0.0013 and the coefficient of variation of 2.69% was experimentally achieved. Theoretical simulation of the feedback strength on the measuring accuracy shows that the measuring method of the damping factor has high accuracy in the case of weak feedback.