Fig. 1. Cross section of PM-PCF

Fig. 2. Filling device

Fig. 3. Side views of PM-PCF before and after ethanol filling. (a) Before ethanol filling; (b) after ethanol filling

Fig. 4. Welding diagrams of PM-PCF and SMF. (a) With collapse; (b) with bubble; (c) perfect fusion

Fig. 5. Sagnac temperature sensing experiment system based on PM-PCF

Fig. 6. Transmission spectrum of raw PM-PCF based on Sagnac interference effect

Fig. 7. Transmission spectra and relationship between interference dip wavelength and temperature for raw PM-PCF at different temperatures. (a) Transmission spectra; (b) relationship between interference dip wavelength and temperature

Fig. 8. Interference dip wavelength of raw PM-PCF during heating and cooling process

Fig. 9. Strain control device of PM-PCF

Fig. 10. Transmission spectra and relationship between interference dip wavelength and strain for raw PM-PCF at different strains.(a) Transmission spectra; (b) relationship between interference dip wavelength and strain

Fig. 11. Interference dip wavelengths of raw PM-PCF during strain increasing and decreasing process

Fig. 12. Transmission spectrum of ethanol-filled PM-PCF based on Sagnac interference effect

Fig. 13. Transmission spectra and relationship between interference dip wavelength and temperature for ethanol-filled PM-PCF at different temperatures. (a) Transmission spectra; (b) relationship between interference dip wavelength and temperature

Fig. 14. Interference dip wavelengths of ethanol-filled PM-PCF during heating and cooling process