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

Abstract

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 CO2 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.