Optical fiber, and system and method for manufacturing optical fiber

A method for manufacturing the optical fiber comprising preparing an optical fiber preform;

• melting and annealing process the optical fiber preform;
• and coating and curing the optical fiber preform, wherein
• the optical fiber preform comprises a fiber core rod, an inner cladding precursor, an intermediate cladding precursor and an outer cladding precursor, and preparing the optical fiber preform comprises:
• shaping the fiber core rod by axial vapor deposition, the fiber core rod comprising undoped silica,
• doping the inner cladding precursor with fluorine, and preparing the inner cladding precursor by chemical vapor deposition, and forming an inner cladding layer with the fluorine-doped cladding precursor,
• adjusting a doping content of fluorine to control a relative refractive index difference between the inner cladding layer and the fiber core,
• making the outer cladding precursor of undoped silica by vapor deposition,
• preparing the optical fiber preform according to a thickness ratios of the fiber core, the inner cladding layer, the intermediate cladding layer, and the outer cladding layer,
• the melting and annealing processes comprises:
• drawing the optical fiber preform into fibers by a fiber drawing furnace, monitoring a radius of the fiber core, a thickness of the inner cladding layer, a thickness of the intermediate cladding layer and a thickness of the outer cladding layer,
• and controlling a drawing speed, so that the fiber core having a radius of 5 μm to 7 μm, the inner cladding layer having a thickness of 5 μm to 12 μm, the intermediate cladding layer having a thickness of 12 μm to 25 μm, and the outer cladding layer having a thickness of 25 μm to 45 μm,
• the coating and curing processes comprises:
• coating the optical fiber preform, monitoring a thickness of the optical fiber during the coating process by a coating machine, controlling a coating pressure and/or a temperature of coating solution, so that an inner coating having a thickness of 25 μm to 40 μm, and an outer coating having a thickness of 25 μm to 35 μm, wherein the coating pressure being controlled by a coating mechanism of the coating machine, the temperature of coating solution being controlled by a temperature adjusting system, and the coating solution being polyacrylate.

A system for manufacturing optical fibers comprising a fiber thawing furnace;

• and a coating machine;
• wherein
• the optical fiber is drawn form a fiber preform comprising a fiber core rod, an inner cladding precursor, an intermediate cladding precursor and an outer cladding precursor, the preform being prepared by chemical vapor deposition,
• the fiber drawing furnace comprises a coaxial top gas disc;
• a fiber drawing furnace body;
• and an annealing pipe, wherein the coaxial top gas disc is a vertical annular structure and comprises a plurality of ring-set air inlets comprising air inlets with vertical downward air flow and air inlets with an inclined direction of air flow, the drawing furnace body is cylindrical and hollow for holding the fiber preform, the annealing pipe is funnel-shaped with porous structure for exhausting, each of the optical fibers is made by the fiber drawing furnace and has a fiber core of 5 μm to 7 μm radius, an inner cladding layer of 5 μm to 12 μm thickness, an intermediate cladding layer of 12 μm to 25 μm thickness and an outer cladding layer of 25 μm to 45 μm thickness by controlling of a drawing speed and an internal temperature of the fiber drawing furnace and a temperature of the outlet of the annealing pipe:
• the coating machine comprises a coating mechanism;
• a temperature adjusting system for coating solution;
• and a control unit, wherein each of the coating mechanism and the temperature adjusting system is electrically connected with the control unit, the coating mechanism being adapted to coat a coating solution on a surface of the optical fibers, and adjust a coating pressure by the control unit, the temperature adjusting system being adapted to regulate a temperature of the coating solution by the control unit, the optical fibers being coated by the coating machine to form an inner coating of 25 μm to 40 μm thickness and an outer coating of 25 μm to 35 μm thickness under the control of the coating pressure and the temperature of the coating solution.