Minimization of conical particles in carbon coatings of optical fibers prepared by thermal chemical vapor deposition

Growth of conical particles in carbon films deposited on silica glass fibers prepared by thermal chemical vapor deposition is investigated. The results show that the size and number of conical particles on the silica glass fiber increase with the film thickness and deposition temperature, but this effect is reduced when the carbon films are deposited on silica glass plates. The growth of conical particles on the silica glass fiber is mainly due to the small cross-sectional area of the fibers. These conical particles are against the hermetic property of carbon-coated optical fibers. We propose a method to minimize conical particles in carbon films on silica glass fibers. (C) 2008 Society of Photo-Optical Instrumentation Engineers.