| 摘要 |
PROBLEM TO BE SOLVED: To provide a means capable of manufacturing a high quality optical fiber preform with a reduced transmission loss increase, which is derived from OH groups, by a collapse method. SOLUTION: With an insertion of a glass rod into a glass pipe or without an insertion of a glass rod, a gas (ionization gas) is introduced into the pipe which is shut off from the air outside and an ionized gas is generated in the pipe. By utilizing functional characteristics of the ionized gas, adsorbed water or the like on the inner surface of the pipe and on the surface of the rod is removed chemically, thermally, and by etching. Removal of the adsorbed water can be done under controlled conditions by applying supplementally heating and selecting the kind of gas. COPYRIGHT: (C)2006,JPO&NCIPI |
