“…Typically, the interference between the coherent reflections and the resonant light is measured by the integrated photodiode placed inside the laser cavity; thus, the induction of interference does not require any external components. Till date various methodologies have been developed to extract the vibration information from the self-mixing interferometric (SMI) signal such as fringes detection [12] , Hilbert transforms [10] , [13] , pre-feedback mirror [14] , digital closed-loop [15] , wavelet transform [16] , phase unwrapping [17] , Genetic algorithm method [18] , envelope extraction using Fourier transform [19] , local maximum detection method [20] and quadrature demodulation [21] . These methodologies provide robust vibration measurement schemes with nanometric resolution up to 40 nm.…”