RARE-EARTH ELEMENT AND HALOGEN ELEMENT-DOPED QUARTZ GLASS-BASED OPTICAL FIBER PREFORM AND ITS PRODUCTION

• Main Authors: EDAKAWA NOBORU, KAMIYA KAZUO, MIMURA HIDENORI, YOSHIDA HISAHIRO, KONYA YOSHIHARU
• Format: Patent
• Language: English
• Published: 26.09.1991
• Subjects: CHEMICAL COMPOSITION OF GLASSES, GLAZES, OR VITREOUSENAMELS; CHEMISTRY; GLASS; JOINING GLASS TO GLASS OR OTHER MATERIALS; MANUFACTURE, SHAPING, OR SUPPLEMENTARY PROCESSES; METALLURGY; MINERAL OR SLAG WOOL; SURFACE TREATMENT OF FIBRES OR FILAMENTS MADE FROM GLASS,MINERALS OR SLAGS; SURFACE TREATMENT OF GLASS

PURPOSE:To improve the luminous efficiency by doping the quartz glass forming the core of an optical fiber preform with a rare-earth element and a halogen element. CONSTITUTION:The quartz glass forming the core is allowed to contain >=50ppm a rare-earth element (e.g. Nd, Er, Eu and Ce) and >=3000ppm a halogen element (selected from Cl, Br and I) to obtain the rare-earth element and halogen element-doped quartz glass-based optical fiber preform. The clad is formed with a fluorine-doped quartz glass. To produce the preform, the silica fine powder generated by the flame hydrolysis of an Si compd. such as SiCl4 is deposited to obtain a porous glass preform (having 0.3-10g/cm bulk density). The preform is then impregnated with a soln. of a rare-earth element compd. (alcohols such as methanol are used as solvent, and the concn. is preferably controlled to >=0.1wt.%), dried, heat-treated at 200-1200 deg.C in the presence of a gaseous halide and heated up to 1200-1800 deg.C to obtain a core, and the core is integrated with the clad.