Patent ID: 9086524
Filing Date: 2015-07-21
Classification: C03B,C03C,G02B,Y02P

Abstract:
1. A method for manufacturing an optical fiber preform, the method comprising: a) providing a lining tube as a substrate tube, the lining tube being a pure quartz glass lining tube; the pure quartz glass lining tube having an outer diameter between 45-55 mm, a wall thickness between 2-4 mm, and a hydroxyl content being equal to or smaller than 0.10 ppm; b) doping and depositing by a plasma chemical vapor deposition (PCVD) or modified chemical vapor deposition (MCVD) process, comprising transporting a reacting gas comprising silicon tetrachloride and oxygen into the lining tube of a), introducing a fluorine-containing gas into the reacting gas for fluorine doping, introducing germanium tetrachloride into the reacting gas for germanium doping, ionizing the reacting gas, the fluorine-containing gas, and the germanium tetrachloride in the lining tube through microwaves to form plasma, depositing on an inner wall of the lining tube a glass, and according to doping requirements of a waveguide structure of optical fiber, changing flow rates of the fluorine-containing gas and the germanium tetrachloride introduced into the reacting gas to deposit a depressed cladding layer, an inner cladding layer, and a core layer in sequence to obtain a deposited lining tube; c) after the completion of deposition, processing the deposited lining tube of b) into a solid core rod by melt contraction through an electric heating furnace; d) sleeving the solid core rod of c) into a pure quartz glass jacketing tube to produce an optical fiber preform, a difference between a diameter of an inner hole of the pure quartz glass jacketing tube and a diameter of the solid core rod being between 1.5 and 4 mm; or directly depositing a pure SiO e) allowing an effective diameter (d) of the optical fiber preform obtained in d) to be between 95 and 205 mm.