Fig. 1. Refractive index change of graphene fiber with temperature and mode field distribution at different temperatures

Fig. 2. Temperature-loss curves under different beam waist diameters

Fig. 3. Temperature-loss curves under different graphene layers

Fig. 4. Graphene transfer process. (a) Copper foil with graphene on the surface; (b) dissolution of the copper foil; (c) graphene transferred to fiber

Fig. 5. Raman spectra of graphene under different cone lengths. (a) L=0 mm; (b) L=5 mm; (c) L=8 mm; (d) L=10 mm

Fig. 6. SEM image after transferring graphene

Fig. 7. Temperature sensing experiment system

Fig. 8. Spectra of TMMFs with different beam waist diameters without graphene modification as temperature increases. (a) d=9.95 μm; (b) d=12.87 μm; (c) d=16.20 μm; (d) d=125 μm

Fig. 9. SG-TMMF spectra with increasing temperature. (a) d=9.95 μm; (b) d=12.87 μm; (c) d=16.20 μm

Fig. 10. Temperature sensing experiment results of 12.87 μm experiment group

Fig. 11. Transmission loss of SG-TMMFs with different graphene lengths versus temperature. (a) l=2 mm; (b) l=4 mm; (c) l=5 mm; (d) l=8 mm

Fig. 12. Relationship curve between wavelength drift and temperature change