Method of fabricating optical fiber using an isothermal, low pressure plasma deposition technique

摘要

An isothermal, low pressure-based process of depositing material within a substrate has been developed and results in creating an extremely narrow reaction zone within which a more uniform and efficient deposition will occur. Sets of isothermal plasma operating conditions have been found that create a narrow deposition zone, assuring that the deposited material is clear glass rather than soot particles. The chemical delivery system, in one arrangement, utilizes rods of solid phase source material (which may otherwise be difficult to obtain in gaseous form). The operating conditions are selected such that the hot plasma does not transfer a substantial amount of heat to the substrate tube, where the presence of such heat has been found to result in vaporizing the reactant material (creating soot) and developing hot spots.

主权项

1. A deposition process for depositing a first material on an inner wall of a substrate tube, the process comprising the steps of:
disposing a substrate tube within a flux of a plasma generator; providing a desired gas composition to the interior of the substrate tube; maintaining an internal pressure within the substrate tube; creating an isothermal plasma within the substrate tube; inserting at least one solid into an end of the substrate tube, wherein at least a portion of the solid is disposed within a narrow zone upstream of the created isothermal plasma, the at least one solid comprising at least one second material and the narrow zone being no greater than 1% of the length of the substrate tube; and vaporizing the solid to form the deposited first material, such that the deposited first material comprises at least a constituent of the second material.