PRODUCTION OF OPTICAL FIBER PREFORM

• Main Authors: ITO MASUMI, HOSHINO SUMIO, DANZUKA TOSHIO
• Format: Patent
• Language: English
• Published: 06.05.1994
• Edition: 5
• Subjects: CHEMISTRY; GLASS; MANUFACTURE, SHAPING, OR SUPPLEMENTARY PROCESSES; METALLURGY; MINERAL OR SLAG WOOL

PURPOSE:To obtain a single-mode optical fiber preform having a refractive index distribution free from the spreading at the skirt part and having excellent transmission characteristics by using an auxiliary burner placed between a burner for core and a burner for clad and blasting oxyhydrogen flame containing a fluorine-containing gas against the side face of a porous glass for core. CONSTITUTION:In the deposition of glass soot for core synthesized by a burner for core and glass soot for clad synthesized by a burner for clad, an oxyhydrogen flame containing a fluorine-containing gas (e.g. CF4) is blasted against the side face of a porous glass for core through an auxiliary burner placed between the core burner and the clad burner to form a porous glass material on the side of the porous glass for core. For example, a burner 1 for core is supplied with SiCl4, GeCl4, H2, O2 and Ar and a burner 2 for clad is supplied with SiCl4, H2, O2 and Ar to synthesize a porous material 9 for core and a porous material 10 for clad. In the above process, H2, O2, Ar and CF4 are supplied to an auxiliary burner 15. The obtained porous material is converted to a transparent glass.