Fig. 1. The cross-section of the As₂S₃ PCF

Fig. 2. Spatial distributions of FOMs with different AFFs at pump wavelengths of (a) 2 μm, (b) 4 μm and (c) 6 μm

Fig. 3. The effective mode area of FOMs with different AFFs at pump wavelength from 2 μm to 6 μm.

Fig. 4. (a) The spatial distribution of the FSM. (b) The dispersion of the refractive index of FSMs with different AFFs

Fig. 5. The normalized frequency V versus pump wavelengths at different AFFs

Fig. 6. The effective refractive index of FOMs with different AFFs at pump wavelengths from 2 μm to 6 μm.

Fig. 7. Spatial distributions of acoustic modes with different AFFs and pump wavelengths. The acoustic modes in each case in the figure are L₀₁-like, L₀₂-like and L₀₃-like modes from left to right

Fig. 8. BGS at an AFF of 0.5 and a pump wavelength of 6 μm

Fig. 9. BGS at an AFF of 0.5 and a pump wavelength of 2 μm

Fig. 10. The BGS for interaction between the L₀₁-like acoustic mode and the FOM as a function of pump wavelength for PCF with an AFF of (a) 0.5 and (b) 0.6. The 0 dB in (a) and (b) respectively correspond to 2.413×10⁻¹⁰ m/W and 2.429×10⁻¹⁰ m/W.

Fig. 11. The relative Brillouin threshold for PCFs with AFFs of 0.5 and 0.6 versus the pump wavelength.