Plasma chemical vapor deposition process
AssigneeDraka Comteq B.V.
InventorsIgor Milicevic, Mattheus Jacobus Nicolaas Van Stralen, Gertjan Krabshuis, Antonius Henricus Elisabeth Breuls
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Abstract
A method for manufacturing a primary preform for optical fibers via an internal plasma chemical vapor deposition (PCVD) process in a hollow silica substrate tube having a supply side and a discharge side includes depositing doped or non-doped silica layers on the inner surface of the hollow substrate tube by supplying glass-forming gasses to the interior of the hollow substrate tube via the supply side thereof, and by creating a plasma reaction zone in the interior of the hollow substrate tube via microwave radiation having a microwave power, wherein the microwave power is decreased during the depositing.
Claims20
A method for manufacturing a primary preform for optical fibers by means of an internal plasma chemical vapor deposition (PCVD) process in a hollow silica substrate tube, the hollow substrate tube having a supply side and a discharge side, which method comprises depositing doped or non-doped silica layers on the inner surface of the hollow substrate tube by supplying glass-forming gasses to the interior of the hollow substrate tube via the supply side thereof, and by creating a plasma reaction zone in the interior of the hollow substrate tube by means of microwave radiation having a microwave power, wherein the microwave power is decreased during the depositing, wherein the microwave-power is decreased continuously during a decrease comprising two or more stages of microwave-power decrease, and wherein a degree of the microwave-power decrease in each stage is larger than the degree of the microwave-power decrease in the immediately preceding stage thereof.
A method for manufacturing a primary preform for optical fibers by means of an internal plasma chemical vapor deposition (PCVD) process in a hollow silica substrate tube, the hollow substrate tube having a supply side and a discharge side, which method comprises depositing doped or non-doped silica layers on the inner surface of the hollow substrate tube by supplying glass-forming gasses to the interior of the hollow substrate tube via the supply side thereof, and by creating a plasma reaction zone in the interior of the hollow substrate tube by means of microwave radiation having a microwave power, wherein the microwave power is decreased during the depositing, and wherein the microwave-power decrease is a linear decrease.
A method for manufacturing a primary preform for optical fibers by means of an internal plasma chemical vapor deposition (PCVD) process in a hollow silica substrate tube, the hollow substrate tube having a supply side and a discharge side, which method comprises depositing doped or non-doped silica layers on the inner surface of the hollow substrate tube by supplying glass-forming gasses to the interior of the hollow substrate tube via the supply side thereof, and by creating a plasma reaction zone in the interior of the hollow substrate tube by means of microwave radiation having a microwave power, wherein the microwave power is decreased during the depositing, and wherein the microwave-power decrease is a quadratic decrease.
Dependencies are inferred from the claim text.