Method and apparatus for manufacturing optical fiber preform using MCVD with preheating process

Abstract

When an optical fiber preform is manufactured using MCVD (Modified Chemical Vapor Deposition), dehydration gas supplied into a tube on which soot particles are deposited is preheated at 600 to 1200° C. so that an internal temperature of the tube is kept over 500° C. in order to improve efficiency of the dehydration process for removing hydroxyl groups. At this time, a preheater for preheating is installed near a front end of the tube where the dehydration gas is introduced, or installed at a predetermined position of a gas supply line, or installed on a gas path in a main pillow. In addition, the preheater is capable of controlling thermal capacity, and a heatproof plate is installed around the preheater.

Dependencies are inferred from the claim text.