| 摘要 |
PURPOSE:To provide a preform for a low loss optical fiber capable of transmitting infrared rays in the wavelength zone of 2-6mum by doping matrix glass with PbF2 or BiF3 to prepare the core and by doping the matrix glass with LiF, NaF or AlF3 to prepare the clad. CONSTITUTION:Glass having a composition consisting of 28-38mol% BaF2, 0- 7mol% GdF3 and 58-69mol% ZrF4 is used as matrix glass. To prepare glass for a core 100mol% said matrix glass is blended with <=6mol% PbF2 or <=16mol% BiF3 as a dopant, and to prepare glass for a clad 100mol% said matrix glass is blended with <=24mol% LiF, <=12mol% NaF or <=8mol% AlF3 as a dopant. A rod made of said core glass is put in a pipe made of said clad glass, and the clad glass is melted, put closely together to the core rod, maintained at a temp. below the glass transition temp., and slowly cooled to obtain a preform. |
