Single Crystal Ge Core Fiber Produced via Pressure Assisted Melt Filling and CO2 Laser Crystallization

We present a simple two step process for the fabrication of single crystal germanium core fibers. Germanium is deposited into a capillary in a highly polycrystalline state using the pressure assisted melt filling technique. This core material is then melted and recrystallized in single crystal form using a scanning CO
₂
laser process. This combination of techniques is an efficient means of producing fibers of practical lengths and core sizes for optical and optoelectronic devices. We produce small core fibers of
$\mathrm {1~ \mu \text {m} }$
radii and lengths in the centimeter regime. It is anticipated that this process can be optimized so that sub-micron cores can be produced to create fibers that have single-mode operation.