| 摘要 |
PROBLEM TO BE SOLVED: To obtain a basic material for optical fiber by grinding at a given level the surface of a porous glass basic material doped with a dopant followed by sintering and vitrifying the material so as to uniformly distribute the dopant radically. SOLUTION: The dopant to be used is e.g. Er, Al, Ge. First, as glass stock gases, silicon tetrachloride and germanium tetrachloride each bubbled with a carrier gas and aluminum chloride sublimated by heating through vapor phase method are subjected to flame hydrolysis in an oxyhydrogen flame to produce fine glass particles, which are then accumulated on a rotating target and grown axially to obtain a porous glass basic material. Secondly, the basic material is heated to about 1,200 deg.C so as to adjust its density to 0.4-0.5g/cm<3> , and then impregnated with a methanol solution of an erbium halide by solution impregnation method, and dried to effect doping Er at 50-3,000ppm. Subsequently, the surface of the resultant basic material is ground at >=5wt.%, and then the basic material is sintered and vitrified e.g. in an atmosphere of He, Cl or the like at 1,400-1,600 deg.C. |
