Abstract: An optical fiber comprises, from a center to a periphery, a fiber core of undoped silica; a cladding layer; and a coating of polyacrylate, wherein the fiber core has a radius of 5 to 7 ?m and an ellipticity of less than 1.5%, the cladding layer with an ellipticity of less than 0.4% comprises inner, intermediate, and outer cladding layers, the inner cladding layer being doped with fluorine of 5 to 12 ?m thickness, and refractive index difference to fiber core of ?0.4 to ?0.2%, the outer cladding layer being undoped quartz of 25 to 45 ?m thickness, and the coating comprises an inner coating of 25 to 40 ?m thickness, and an outer coating of 25 to 35 ?m thickness and an ellipticity of less than 2%. The optical fiber has high durability and large effective transmission area, a method and system for preparing such optical fiber are also disclosed.

Abstract: A method for producing a depressed-cladding core rod of an ultra-low water peak optical fiber, the method including 1) producing a core rod component; 2) producing an inner cladding casing component; 3) disposing the core rod hollow shaft and the casing hollow shaft respectively in the glass lathe; 4) cutting off connections among a pressure controlling pipe, a scrubber, and a vacuum pump; 5) connecting the inner cladding casing to the core rod hollow shaft hermetically; 6) turning on the glass lathe; 7) transporting a first mixture gas to the core rod hollow shaft; 8) moving a high temperature heat source; 9) transporting a second mixture gas to the core rod hollow shaft; 10) transporting the first mixture gas to the core rod hollow shaft; 11) transporting the first mixture gas under certain conditions; and 12) controlling relevant parameters to fuse the inner cladding casing with the core layer rod.

Abstract: An apparatus and a method for producing a depressed-cladding core rod of an ultra-low water peak optical fiber, the apparatus including a core rod component, an inner cladding casing component, a high temperature heat source, chucks, a rotary joint, an external gas pipe, and a pressure controlling pipe. The core rod component is produced by fusing and splicing a core layer rod and a first hollow shaft together. The inner cladding casing covers the outside of the core layer rod. The inner cladding casing component is produced by fusing and splicing an inner cladding casing and a second hollow shaft together. These two hollow shafts are clamped in two chucks of a glass lathe. A high temperature heat source is arranged outside the inner cladding casing.