Fig. 1. Self-mixing model

Fig. 2. Diagram of electro-optic modulation laser self-mixing system

Fig. 3. Proportionality factor of tangent function. (a) First and second-order Bessel function curves; (b) proportional factor variation curves caused by phase difference

Fig. 4. Variation of standard deviation with scale factor K

Fig. 5. Block diagram of normalized electro-optic orthogonal demodulation

Fig. 6. Experimental setup for electro-optic demodulation self-mixing

Fig. 7. Self-mixing signal. (a) Electro-optical modulation self-mixing signal; (b) self-mixing signal spectrum

Fig. 8. Harmonic signals. (a) Non-normalized first-order harmonic; (b) non-normalized second-order harmonic; (c) normalized first-order harmonic based on maximum; (d) normalized second-order harmonic based on maximum; (e) normalized first-order harmonic based on Hilbert transform; (f) normalized second-order harmonic based on Hilbert transform

Fig. 9. Measurement results. (a) Displacement curves; (b) error curves

Fig. 10. Standard deviation of normalization and non-normalization measurements

Fig. 11. Reconstructions of vibrations with different waveforms. (a) Triangular wave; (b) error of triangular wave; (c) square wave; (d) error of square wave