Fig. 1. Structure of saltwater cavity

Fig. 2. Structure of double parallel cavity

Fig. 3. Interference spectra of single cavity and parallel double cavity with different salinities

Fig. 4. Schematic diagram of optical fiber salinity sensing experimental setup

Fig. 5. Microscope image of saltwater cavity and air cavity

Fig. 6. Variation of saltwater cavity interference spectrum and peak wavelength with temperature

Fig. 7. Variation of air cavity interference spectrum and peak wavelength with temperature

Fig. 8. Variation of sensor interference spectrum and peak wavelength with temperature

Fig. 9. Variation of saltwater cavity interference spectrum and peak wavelength with salinity

Fig. 10. Variation of sensor interference spectrum and peak wavelength with salinity

Fig. 11. Sensor repeatability and stability test results