| 摘要 |
PURPOSE:To obtain a high-purity optical fiber preform by heating and purifying a specified porous preform in a treating gas atmosphere followed by sintering to effect transparent vitrification with tubular structure. CONSTITUTION:A crosshead 32 is prepared by providing (A) a plastic stock 41 for core comprising germanium oxide-doped silica powder, water, and binder, etc., (B) a second plastic stock 43 for cladding use comprising silica powder, water, and binder, etc., (C) pipings 16, 26, and (D) a center ball etc. Thence, the crosshead 32 is fed with the stocks 41, 43 to carry out extrusion molding to obtain a porous preform 46 with tubular structure composed of core 42 and clad 44 with an axially penetrating hole made by the action of the center ball 11. The preform 46 is then dried, degreased, purified, dehydrated, and sintered to effect transparent vitrification, thus obtaining the objective optical fiber preform. |
