| 摘要 |
PURPOSE:To obtain the optical fiber porous preform with the effective deposition part maximized by using plural burners spaced apart from each other by a specified distance to deposit glass fine particles on a carrier by outside CVD method. CONSTITUTION:A gaseous silicon compd. such as silicon tetrachloride is introduced into an oxyhydrogen flame burners 3-1, 3-2,..., and hydrolyzed, and the obtained glass fine particles 4 are deposited on the heat-resistant carrier 2 of synthetic quartz, silicon carbide, carbon, etc., to form the optical fiber porous preform 1. At least two burners (3-1 and 3-2) are used to form an effective deposition part, and the distance between the burners is controlled to >=4 times the burner diameter. Consequently, the yield of the glass fine particles deposited on the effective deposition part is adjusted to >=85%. When the burner is moved to both ends of the carrier 2, the distance between burners is controlled to <=3 times the burner diameter. The tapered part is minimized in this way. |
