PRODUCTION OF FIBER ROD FOR OPTICAL ATTENUATOR

摘要

PROBLEM TO BE SOLVED: To provide a method for providing a fiber rod for optical attenuator, optimizing outer diameter of Co dope region in a fiber. SOLUTION: A glass rod having a distribution such as broken line is produced by a conventional method and the outer periphery is etched with hydrofluoric acid, etc., to provide a Co doped glass rod 4 in which Co is uniformly distributed from the center to the outer periphery. The Co doped glass rod 4 is inserted into a transparent quartz tube 5 having same index of refraction as that of the Co doped glass rod 4 to carry out jacketing. Thereby, Co dope region having a radius (c) is accurately set in a core having a radius (a).