PREPARATION METHOD OF PREFORM FOR OPTICAL FIBERS

摘要

A preform of optical fibers is prepared by the stages of: manufacturing a glass cylinder having the refractive index distribution of an axis symmetry by vapor axial deposition method, changing a tube by drilling a hole at its center, separately preparing a glass cylinder having the same refractive index distribution by vapor axial deposition method, treating it in the given diameter by drawing method, inserting it into the tube, heating and uniting in a single body.