The influence of core geometry on the crystallography of silicon optical fiber

Advanced Multimaterial Electronic and Optoelectronic Fibers and Textiles

“…The annealed fiber exhibited improved local crystallinity, and single crystals with a length of nine millimeters were reported. Furthermore, the nature of the crystallographic orientation of the core material relative to the fiber axis and the influence of core geometry on the crystallography were investigated . In another study, multistep annealing of the amorphous silicon core below its melting point in a silica optical fiber was reported.…”

Glass and Process Development for the Next Generation of Optical Fibers: A Review

“…Following the first in-depth analysis of the longitudinal single-crystallinity in these fibers [120], methods investigated to either refine or recrystallize the crystalline semiconductor core include thermal annealing [121], core geometry (circular versus square cross-section) [122], core size [117], It is also important to note that, unlike traditional glass fibers, additional solid-state and liquid-phase chemistry not only can take place during the fabrication of these fibers, but can be strategically employed. Two excellent examples are the fabrication of zinc selenide (ZnSe) fibers using Zn and Se compounds [111,113] and silicon fibers realized from aluminum [114]; in both cases, reactions occur in-situ during the draw, opening the door to an even richer range of materials and chemical/process routes to intriguing new fibers not possible using conventional methods.…”

“…Following the first in-depth analysis of the longitudinal single-crystallinity in these fibers [120], methods investigated to either refine or recrystallize the crystalline semiconductor core include thermal annealing [121], core geometry (circular versus square cross-section) [122], core size [117], tapering [123] and laser recrystallization [124,125]. These processes do indeed influence the single crystallinity of the semiconductor core and have led to longer single crystalline lengths and slightly lower losses [95].…”

Silicon optical fibres – past, present, and future

“…Further to this, silicon core fibres can be tapered at temperatures above the melting point of the silicon, but where the silica cladding glass can still be controllably deformed. As well as allowing for precise tailoring of the core size [29], this tapering process has also been shown to enhance and control the crystallographic orientation of the silicon with respect to the fibre axis [30,31]. While not necessarily germane to cubic silicon, crystallographic control would be of great value to non-cubic, hence potentially χ (2) -active semiconductor core phases.…”