Statistics of the self-mixing speckle interference in a laser diode and its application to the measurement of flow velocity

The statistical analysis of self-mixing speckles interference using Fabry–Perot cavity is described based on the theory of the speckle and the self-mixing interference in a laser diode. Speckle signal processing based on Fourier transform is presented in this paper. The linear dependence between the spectrum mean frequency and velocity of solution is given by simulation and proved by experiment. The experimental results show that this speckle signal processing can be used to measure velocity of target.