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: 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.