Fig. 1. (a) Schematic illustration of the double-clad As2Se3 PCF, (b) the electric field distribution of the fundamental optical mode, (c) the acoustic displacement distribution of the fundamental acoustic mode, and (d) the BGS of the As2Se3 PCF structure with d1=0.8  μm, d2=1.2  μm, and Λ=2  μm.

Fig. 2. BGS of three double-clad As2Se3 PCF structures with (a) d2=1.2  μm, Λ=2  μm and d1=0.8, 1.2, and 1.6 μm; (b) d1=0.8  μm, Λ=2  μm, and d2=0.8 , 1.2, and 1.6 μm.