Fig. 1. Schematic of sensor probe with single structure defect

Fig. 2. Schematic of liquid leakage sensor

Fig. 3. The effect of duty cycle and frequency on side coupling rate

Fig. 4. The influence of duty ratio and frequency on insertion loss

Fig. 5. FBG morphs under a 15-fold laser microscope

Fig. 6. Overall design of LED control system

Fig. 7. 12 V to 5 V buck circuit

Fig. 8. 5 V to 3.3 V voltage conversion between communication serial port USB and the main chip

Fig. 9. Master chip design

Fig. 10. Communication flow of upper computer

Fig. 11. The third light is on in the specified mode

Fig. 12. The lights are switched on in turn in cycle mode

Fig. 13. Sudden changes in the output of the power meter caused by fluid leakage