| 摘要 |
PURPOSE:To inhibit foam generation by lowering the temp. at the intergration stage of a core rod and a clad pipe and to obtain the titled preforms having large difference in the refractive indices by the simultaneous melting method by using a quartz glass rod contg. Ge for a core and a quartz glass pipe added with fluorine for a clad. CONSTITUTION:A core rod having high refractive index is inserted into a clad pipe having low refractive index, and the clad pipe inserted with the core rod is heated from the external peripheral part to integrate the core rod and the clad pipe by melting both at the same time. Thus a preform for optical fiber is prepd. In this process, quartz glass contg. GeO2 corresponding to <=1.5% specific refractive index difference is used as the core rod material and quartz glass added with fluorine corresponding to the amt. resulting <=-0.3% specific refractive index difference is used for the material for the clad pipe. Thus, the temp. at integration can be reduced and foam generation is retarded and a preform for optical fiber having high refractive index difference is prepd. without causing breakage or damage. |
