A novel extension
to the molten core method was employed to realize
a glass-clad, crystalline gallium arsenide (GaAs) core fiber for the
first time to the author’s knowledge. GaAs is of considerable
interest for its optoelectronic and nonlinear properties, but decomposition
and volatility, usually leading to incongruent solidification, normally
preclude melt-processing under ambient conditions into an optical
fiber. Presented here are results on tin as a flux to melt GaAs at
a temperature where volatility is negligible, permitting the thermal
drawing of long lengths (100 m) of glass-clad, crystalline GaAs-containing
fibers. Laser annealing is employed to segregate the Sn and GaAs phases,
both across and along the fiber. This work presents an important new
tool for scalable fabrication of glass-clad crystalline core materials
previously thought incompatible with molten core processes and opens
the door to a wide range of novel and useful in-fiber optoelectronic
devices.