OPTICAL FIBER

• Main Authors: UESUGI SUNAO, KAMIYA TAMOTSU, ISHIDA YUKINORI, HIGASHIMOTO MASAKAZU, FURUI YASUROU, YOSHIDA KAZUAKI, KOKAYU MIKIO
• Format: Patent
• Language: English
• Published: 11.05.1985
• Subjects: CHEMICAL COMPOSITION OF GLASSES, GLAZES, OR VITREOUSENAMELS; CHEMISTRY; GLASS; JOINING GLASS TO GLASS OR OTHER MATERIALS; METALLURGY; MINERAL OR SLAG WOOL; OPTICAL ELEMENTS, SYSTEMS, OR APPARATUS; OPTICS; PHYSICS; SURFACE TREATMENT OF FIBRES OR FILAMENTS MADE FROM GLASS,MINERALS OR SLAGS; SURFACE TREATMENT OF GLASS

PURPOSE:To obtain an optical fiber maintaining its reliability for a long term by increasing the concn. of P2O5 in a core from the central part toward the periphery and specifying the P2O5 content of the central part and the average P2O5 content of the core. CONSTITUTION:An optical fiber 1 is manufactured by spinning a base material for an optical fiber formed by an MCVD method or a VAD method. The core 2 of the fiber 1 is made of synthetic GeO2-P2O5-SiO2 glass and has 50mum outside diameter. The clad 3 is made of quartz glass and has 125mum outside diameter. The inner layer of the clad 3 having <=10mum thickness is made of synthetic F-P2O5-SiO2 glass, and the remainder is made of SiO2. The primary coating layer 4 is made of thermosetting resin and has 400mum outside diameter. The secondary coating layer 5 is made of thermoplastic resin and has 900mum outside diameter. A test of the fiber 1 at a high temp. makes it clear that the reliability of the fiber 1 is maintained for a long term by increasing the concn. of P2O5 in the core 2 from the central part toward the periphery and regulating the P2O5 content of the central part of the core to <=0.7wt% and the average P2O5 content of the core to 0.2-1.0wt%.