  With the ultimate goal of developing rare-earth doped chalcogenide fiber
fabrication for sensing, amplification, and laser applications, a core/clad
germanium-gallium sulfide fiber doped with Pr$^{3+}$ has been fabricated. The
compositions of the core and the clad were selected to ensure the positive
$\Delta$n by adding CdI$_2$ and CsCl, respectively, in the GeS$_2$ -Ga$_2$S$_3$
matrix. The choice of these compositions was also justified from experimental
parameters, including characteristic temperatures and viscosity. Moreover, the
permanent photo writability of the sulfide glass family by a femtosecond laser
is investigated from the perspective of Bragg grating photo-inscription.
Structural investigations by Raman spectroscopy are presented and the effect of
the Pr$^{3+}$ rare-earth ion on the structure is underlined. Finally, the
emission of the step-index fiber, made by the rod-in-tube technique between 3.1
$\mu$m and 5.5 $\mu$m (by pumping at 1.55 $\mu$m), is demonstrated.
