Fig. 1. Structure of diaphragm EFPI sensor

Fig. 2. Relationship between output signal and low-frequency infrasound disturbance

Fig. 3. Result of first-order modal analysis by ANSYS

Fig. 4. Relationship between different model parameters and first-order resonant frequency. (a) Diaphragm material; (b) diaphragm thickness; (c) diaphragm radius; (d) diaphragm prestress

Fig. 5. Results of finite element harmonic response analysis by ANSYS (0-10 kHz)

Fig. 6. EFPI sensor. (a) Structural diagram; (b) photograph

Fig. 7. Interference spectrum of EFPI sensor

Fig. 8. Test device of optical fiber EFPI acoustic sensor

Fig. 9. Characterization of sensor characteristics. (a) Frequency response; (b) Sensitivity

Fig. 10. Signal output of sensor under 5 Hz sound source excitation. (a) Time domain; (b) frequency domain

Fig. 11. Signal output of sensor under 1 Hz sound source excitation. (a) Time domain; (b) frequency domain

Fig. 12. Signal output of sensor under 0.5 Hz sound source excitation. (a) Time domain; (b) frequency domain