| 摘要 |
PURPOSE:To manufacture a preform rod for a single polarization type optical fiber at a low cost by arranging a preform rod for a core, preform rods for side pits and rods for spacers in a quartz glass pipe. CONSTITUTION:A preform rod 4 for a core composed of a core part 2 and a clad part 3 is placed in a quartz jacket pipe 1 at the center, and a pair of preform rods 7, 7 for side pits each composed of a side pit part 5 and a side pit clad part 6 are arranged. A plurality of rods 8 for spacers are further arranged in contact with the rods 4, 7. The side pit parts 5 are made of silica contg. B2O3, and the softening temp. is made lower than that of the rod 4, the parts 6 and the rods 8 each made of pure silica. A preform rod for a single polarization type optical fiber capable of stably maintaining a polarization state over a long distance is obtd. inexpensively. |
