METHOD FOR MANUFACTURING OPTICAL FIBER PREFORM, OPTICAL FIBER PREFORM, METHOD FOR MANUFACTURING OPTICAL FIBER AND OPTICAL FIBER

摘要

PROBLEM TO BE SOLVED: To provide a method for manufacturing an optical fiber preform which is small in the specific circular rate of shapes of respective parts at a section. SOLUTION: A rod 40 is formed by manufacturing a core part 30 added with GeO2, forming a supporting part 30A substantially consisting of pure silica glass around the core part 30 and forming a first clad part 31 mixed with an F element around the supporting part 30A. The rod 40 is inserted into an outer clad pipe 39A which is ought to constitute an outer clad part 31. The rod 40 and the outer clad pipe 39A are integrated by heating and are stretched, by which the outer clad pipe 39A is formed as the outer clad part 39. Further, the circumference of the outer clad part 39 is jacketed, by which the optical fiber preform is manufactured.