OPTICAL FIBER

摘要

PURPOSE: To prevent leaking of light by using a noncrystalline fluorine-contg. polymer having no C-H bond to constitute a refractive index distribution type optical fiber, and forming an outer layer with a fluorine-contg. polymer having lower refractive index than the inner layer. CONSTITUTION: The refractive index distribution type optical fiber consists of a noncrystalline fluorine-contg. polymer which does not substantially contain C-H bonds as a matrix. The optical fiber consists of concentric two layers of an outer layer and an inner layer having refractive index distribution. The refractive index of the outer layer is made lower by >=0.001 than that of the outermost part of the inner layer. The inner layer shows such refractive index distribution that the refractive index changes from 1.36 to 1.34 in the radial direction from the center and shows an almost parabolic curve. The outer layer in contact with the inner layer can suppress leaking of light by the difference of the refractive index from the outermost part of the inner layer. The outer layer may be made of two or more layers as far as the refractive index of the outer layer is made lower by >=0.001 than the outermost part of the inner layer.