Fig. 1. The LPFG fabrication system

Fig. 2. (a) Schematic diagram of the periodic straight-line laser-modified structure by fs laser direct writing. (b) Microscope image of LPFG after HF etching. (c) Microscope image of LPFG filling with PDMS

Fig. 3. Initial transmission spectrum of LPFG

Fig. 4. Schematic diagram of the experimental setup for measuring (a) temperature, (b) strain and (c) bending

Fig. 5. (a) Evolution of the transmission spectrum at different temperatures; (b) relationship between the resonance wavelength shift and the temperature

Fig. 6. (a) Evolution of the transmission spectrum at different strains; (b) relationship between resonance wavelength shift and strain

Fig. 7. (a) Evolution of the transmission spectrum at different RI solutions; (b) relationship between resonance wavelength shift and RI

Fig. 8. (a) Evolution of the transmission spectrum at different curvatures; (b) relationship between resonance intensity shift and curvature