  Two structures of circular lattice Photonic Crystal Fibers (PCFs) based on
$Ge_{20}Sb_{15}Se_{65}$ (GSS) material have been proposed for a highly coherent
broadband supercontinuum generation (SCG) in the mid-infrared region. Numerical
studies on both structures show that the fundamental modes are well confined in
the core while the confinement losses are very low. Also, the high nonlinear
coefficient of 22.01 $W^{-1}m^{-1}$ and 17.99202 $W^{-1}m^{-1}$ for the two
structures ensure that these structures can accomplish a high nonlinear
activity. It has been found that broadband supercontinuum (SCs) spanning from
0.45 $\mu$m to 5.3 $\mu$m and 0.48 ${\mu}$m to 6.5 ${\mu}$m can be generated
using a hyperbolic secant pulse of 0.5 kW. The proposed structures also show
very good structural tolerance to optical properties that prevent any radical
shift in SC spectra owing to potential fabrication mismatch.
