PURPOSE: To obtain quartz optical fiber hardly causing increase of transmission loss even if it is exposed in an inferior environment contg. H2 by incorporating fluorine to both core and clad as dopant.
CONSTITUTION: Fluorine is added to both core 2 and clad 3 as dopant, and a dopant for increasing refractive index (e.g. GeO2, P2O5) is added to the clad 2, and a dopant for reducing refractive index (e.g. B2O3 is added to the clad 3; thus, aimed quartz optical fiber 1 is obtd. Incorporation of fluorine is performed in gaseous fluorine atmosphere (e.g. F2, SiF4) in the stage of prepg. porous preform by the external CVD method or VAD method, or by performing in the same atmosphere in the stage of deposition of glass layer on the inside surface of a quartz glass pipe.
ORIMO KATSUMI
IINO AKIRA
OGURA KUNIO
KOKAYU MIKIO
INAGAKI NOBUO
NAKAHARA MOTOHIRO
NIPPON TELEGRAPH & TELEPHONE
| JPS58217450A | 1983-12-17 |
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