Fig. 1. The proposed TSCF sensor

Fig. 2. Transmission spectra of the SMF-TSCF-SMF structure with 29 μm diameter taper，19 μm diameter taper and 11 μm diameter taper

Fig. 3. Transmission spectra of TSCF with different diameters before and after entering water

Fig. 4. Schematic diagram of the ultrasonic detection system

Fig. 5. 1 MHz sensor ultrasonic response

Fig. 6. Sensor stability test

Fig. 7. Experimental measurement

Fig. 8. Ultrasonic response of sensor

Fig. 9. Spectrum response characteristics of sensor to pulsed UWs with frequency of 500 kHz and 5 MHz

Fig. 10. Variation of sensor response amplitude with ultrasonic intensity