Fig. 1. Schematic of HCF. (a) End facet; (b) light guiding mechanism; (c) anti-resonant waveguide transmission; (d) transmission spectrum of anti-resonant waveguide

Fig. 2. Structural diagram of proposed fiber sensor

Fig. 3. Transmission spectrum of SMF-HCF-SMF structure

Fig. 4. Experimental device for UV femtosecond laser inscription of FBG by phase mask

Fig. 5. Transmission spectrum of cascaded HCF and FBG

Fig. 6. Characteristics of temperature response. (a) Transmission spectrum of HCF-FBG sensor during temperature increases; (b) resonance wavelength of HCF or FBG versus temperature

Fig. 7. Device for strain measurement

Fig. 8. Characteristics of strain response. (a) Evolution of transmission spectrum of HCF-FBG sensor during axial strain increases; (b) resonance wavelength of HCF or FBG versus strain