| 摘要 |
PROBLEM TO BE SOLVED: To provide a means of preparing a refractive index profile of a GI-POF through simpler steps and of manufacturing a more stable GI-POF. SOLUTION: This is a manufacturing method of an optical fiber, having an optical transmitting region in which a refractive index is higher at the center than around the periphery, in a plane vertical to the longitudinal direction, and in which a double-refractive index varies starting from the longitudinal center line toward the periphery, in a direction vertical to the longitudinal center line, in a plane parallel to the longitudinal direction and inclusive of the longitudinal center line. The manufacturing method includes an extrusion molding step for the material of the optical transmitting region by using dies of two or more layers, among the dies, of which the temperature difference between the die with the highest extruding temperature and the die with the lowest, is not smaller than 20°C, that it also includes a step of cooling the extrusion molded article, after stretching it, and that it employs the same materials for all of those for the optical transmission region. COPYRIGHT: (C)2007,JPO&INPIT |
