METHODS FOR PREPARING LARGE-DIMENSION OPTICAL FIBER PREFORM AND OPTICAL FIBER

摘要

Methods for preparing a large-dimension optical fiber preform and an optical fiber are provided. The method for preparing the preform comprises steps of depositing a depressed cladding, an inner cladding and a core in sequence inside a fluorine-doped or pure silica glass substrate tube; melting and collapsing the deposited tube to obtain a solid core rod; fitting the solid core rod with a cladding tube to obtain the preform, or depositing an outer cladding surrounding the solid core rod to obtain the preform. The preform is directly drawn to the optical fiber, or it is firstly drawn to a small preform, then the small preform is drawn to the optical fiber. The bare optical fiber is coated with two layers of coating material to obtain a single mode optical fiber with advantages of high fatigue resistance parameter, bending insensitive and low water peak. The preform having large dimension, long drawing length can be obtained by the method. Additionally, the method is simple and cost-efficient, and adapts to large-scale production.