Obtaining Scalable Fringe Precision in Self-Mixing Interference Using an Even-Power Fast Algorithm

We propose a simple and effective even-power fast algorithm to obtain scalable fringe precision in self-mixing interference. In this letter, the principle of the even-power fast algorithm is introduced in detail. The validity of the proposed algorithm is demonstrated by means of simulated signals and confirmed by experimental measurements at different vibration amplitudes. Without adding any additional optical elements in the optical path, theoretical analysis shows that the resolution of the fringe could be enhanced to λ/2
ⁿ⁺³
(n = 0, 1, 2, 3. . .). Experimental results show a fringe precision of λ/32 is achieved at a sampling rate of 50 KS/s. The influence factors are also discussed when the algorithm is applied in actual measurements.