  The advantages of high-quality-factor whispering gallery mode microresonators
can be applied to develop novel photonic devices for the mid-IR range. ZBLAN
(glass based on heavy metal fluorides) is one of the most promising materials
to be used for this purpose due to low optical losses in the mid-IR. We
developed original fabrication method based on melting of commercially
available ZBLAN-based optical fiber to produce high-Q ZBLAN microspheres with
the diameters of 250 to 350 $\mu$m. We effectively excited whispering gallery
modes in these microspheres and demonstrated high quality factor both at 1.55
$\mu$m and 2.64 $\mu$m. Intrinsic quality factor at telecom wavelength was
shown $(5.4\pm0.4)\cdot10^8$ which is defined by the material losses in ZBLAN.
In the mid-IR at 2.64 $\mu$m we demonstrated record quality factor in ZBLAN
exceeding $10^8$ which is comparable to the highest values of the Q-factor
among all materials in the mid-IR.
