Impact of chlorine dissociation for modified chemical vapor deposition

Modified chemical vapor deposition (MCVD) is the platform technology used to create a wide range of silica-based optical fibers. This paper reports on the extension of the reaction scheme embedded within a computational fluid dynamics model of the MCVD process to include chlorine dissociation and recombination. Simulations employing this modified kinetic scheme indicate that chlorine dissociation acts primarily as a ‘heat sink’ in cases where the operating conditions promote a high peak temperature in the narrow reaction zone where most of the SiCl4 oxidation occurs. The extended model allows a wider range of operating parameters to be examined in terms of the deposition profile of silica ‘soot’ particles on the substrate tube wall.