Fig. 1. Schematic of the local heating model of LCFBG

Fig. 2. (a) Transmission spectrum of LCFBG under the different temperature changes ΔT and ΔL=0.25 mm; (b) Central wavelength and transmittance of narrow-band transmission peaks versus ΔT under ΔL=0.25 mm; (c) Period and scanning range of the central wavelength (or transmittance) of narrow-band transmission peaks versus ΔL

Fig. 3. (a) Transmission spectrum of LCFBG under the different heating width ΔL and ΔT=135 ℃; (b) Central wavelength and transmittance of narrow-band transmission peaks versus ΔL; (c) Period of the central wavelength (or transmittance) of narrow-band transmission peaks versus ΔT

Fig. 4. (a) Transmission spectrum of LCFBG under the local heating points located at 6.5 mm,7.5 mm and 8.5 mm from one end of the LCFBG, respectively; (b) Central wavelength and transmittance of transmission peaks versus heating position

Fig. 5. Experimental setup of the local heating of LCFBG

Fig. 6. (a) Infrared thermal imaging of four heating regions on the thermal printhead with a duty ratio of 90%; (b) Temperature curves of one heating region with different consecutive heating elements on the heating array versus heating duty ratio

Fig. 7. (a) Transmission spectra for different heating duty ratios; (b) Central wavelength and intensity of transmission peaks versus heating duty ratio

Fig. 8. Stability of transmission spectra

Fig. 9. (a) Transmission spectra for different heating widths; (b) Central wavelength and intensity of the transmission peaks versus the heating width

Fig. 10. Transmission spectra for different heating positions (Inset: central wavelength of narrow-band transmission peaks versus heating position); (b) Transmission spectra under multi-position heating