Alkaline oxide interface modifiers for silicon fiber production

Abstract

We demonstrate the ability to pull small diameter silicon-core fibers with low oxygen content by using interface modifiers between the silica cladding and the semiconductor. Alkali earths scavenge oxygen and form a fine-structured eutectic that accommodates thermal strain and may be useful as an intermediate index cladding layer for optical applications. NaO, MgO, SrO, CaO and BaO interface modifiers were tested. CaO coated fibers were made with core diameters down to 10 microns, small bending radii, low oxygen incorporation, and optical losses below 4 dB/cm at 1.55 microns.