| 摘要 |
PURPOSE: To make it possible to easily obtain a large-sized optical fiber preform with low transmission loss by dropping a core soln. into a hollow clad pipe which is so arranged as to align its central axis to an approximately perpendicular axial direction and is closed at its bottom end, thereby polymerizing a core. CONSTITUTION: An org. low-molecular material and polymn. initiator constituting a clad 12 are injected into a hollow cylindrical body (for example, glass, etc.) 11 and this cylindrical body 11 is rotated to polymerize the material, by which the tubular clad 12 is synthesized. Next, the polymerized tubular clad 12 is taken out of the cylindrical body 11. The core soln. 13 composed of an org. low-polymer material and a low-polymer compd. having a high refractive index is dropped from a core soln. dropping device 14 into the tubular clad 12 which is closed at the bottom end and is so arranged as to align its central axis to approximately the perpendicular axial direction. The polymn. of the core 15 is then executed. In such a case, the more specific examples of the low- molecular compd. of the high refractive index used for the core 15 include, for example, benzyl ester phthalate, 2-phenyl ethyl acetate, dimethyl phthalate, diphenyl sulfide, benzyl benzoate, etc. |
