On the production mannered null jacket

摘要

PROBLEM TO BE SOLVED: To provide a method for producing an optical fiber having fine pores in its clad and to simply produce an optical fiber of desired characteristics in regard with an optical fiber produced by the production method.;SOLUTION: What is provided is a multicapillary-process optical fiber production method comprising arranging a plurality of glass capillaries in a bundle within a jacket pipe 11 to form a preform 10 and thermally drawing this preform into a fiber, which method is one comprising the preform formation step of disposing a central glass rod 13 having a core part 2 of the glass fiber in a state in which N (wherein N is an integer of 7 or greater) glass capillaries surround the entire circumference of the central glass rod 13 within the jacket pipe 11, wherein at least two of the N glass capillaries are hollow glass capillaries 12, and r=(R+r)*sin(π/N) holds (wherein 2R is the diameter of the central glass rod 13, 2r is the outside diameter of each glass capillary, and 2(R+2r) is the inside diameter of the jacket pipe 11).;COPYRIGHT: (C)2010,JPO&INPIT