Fig. 1. Fiber optic Fabry-Perot ultrasonic sensing system

Fig. 2. Schematic diagram diaphragm based fiber optic Fabry-Perot sensor probe

Fig. 3. Deformation of round diaphragm caused by pressure difference due to temperature

Fig. 4. Deformation caused by temperature difference

Fig. 5. Simulation results of natural frequency of porous sensing diaphragm with different hole radii

Fig. 6. MEMS technology production process of porous sensing diaphragm

Fig. 7. Porous sensing diaphragm sample and its scanning electron microscope image

Fig. 8. Reflection spectrum of fiber optic Fabry-Perot sensor

Fig. 9. Porous sensing diaphragm sensor probe

Fig. 10. Schematic diagram of partial discharge detection experimental setup

Fig. 11. Static pressure response of porous sensing diaphragm EFPI sensors in liquids

Fig. 12. Amplitude-frequency response curve of porous sensing diaphragm EFPI sensor in liquid for standard sine wave signal

Fig. 13. Response curve of porous sensing diaphragm EFPI sensor for discharge released by pulse discharge gun

Fig. 14. Porous sensing diaphragm EFPI sensor in liquid based on signal change of detection distance

Fig. 15. Directional response of porous sensing diaphragm EFPI sensor at distances of 5 and 10 cm in liquid