METHOD FOR COVERING OPTICAL FIBER WITH CARBON

摘要

PURPOSE:To produce a carbon hermetic covering film, which has very small amount of hydrogen content on the surface of an optical fiber and is equipped with waterproofness and water permeation preventing function. CONSTITUTION:The gas pressure in a chamber 2 in which an optical fiber 1 is set is made over 1.5Torr, and high frequency electric power is supplied to a hollow electrode 3 of the chamber 2 to produce plasma 4 around the optical fiber 1, wherein the molar fraction of hydrocarbon gas in the plasma 4 to the hydrocarbon gas in the mixture gas is below 20%.