Fig. 1. (a) Experimental setup. (b) Schematic image of the NH-LPFG.

Fig. 2. Transmission spectra of the NH-LPFG under increasing rotation angles.

Fig. 3. Experimental setup for torsion measurement.

Fig. 4. (a) Transmission spectra and (b) wavelength shift of the NH-LPFG in response to the applied torsion in the non-polarization state.

Fig. 5. Transmission spectra of the NH-LPFG in two polarization states.

Fig. 6. Transmission spectra for the NH-LPFG in (a) 0 rad, (b) π/4  rad, and (c) π/2  rad polarization states under an applied torsion ranging from −18.3 to 18.3 rad/m. (d) Wavelength shift of the NH-LPFG versus the different torsion angles in three polarization states.

Fig. 7. Dependence of the resonance wavelength on temperature.