Fig. 1. Schematic diagram of three wavelength phase compensation demodulation system

Fig. 2. Theoretical demodulation error when cavity length of EFPI sensor varies in the range of 92.1983--112.1983 μm

Fig. 3. Experimental results of EFPI sensor with cavity length of 107.8886 μm under aperiodic dynamic signal. (a) Three interferometric signals; (b) demodulated output signal

Fig. 4. Demodulation results before and after phase compensation during pressure rise

Fig. 5. Demodulation results before and after phase compensation during pressure drop

Fig. 6. Comparison of demodulation accuracies of three laser interferometric demodulation methods. (a) Cavity length variation; (b) relative error