Abstract: The optical fiber comprises a glass fiber comprising a core and a cladding, a primary resin layer in contact with the glass fiber and covering the glass fiber, and a secondary resin layer covering the primary resin layer, wherein the primary resin layer contains a cured product of a resin composition containing a urethane (meth)acrylate oligomer, a monomer, a photopolymerization initiator and an aromatic acid compound, a content of the aromatic acid compound is 20 ppm or more and 12000 ppm or less based on a total amount of the resin composition, and Young's modulus of the primary resin layer is 0.6 MPa or less at 23° C.±2° C.

Abstract: A method for manufacturing an optical fiber includes: a coating step of forming a first layer by applying a first ultraviolet ray curable resin composition onto a glass fiber, and then, of forming a second layer by applying a second ultraviolet ray curable resin composition onto the first layer; a first irradiation step of curing the first layer and the second layer by irradiating the first layer and the second layer with an ultraviolet ray, and of obtaining the optical fiber including a primary resin layer and a secondary resin layer; and a second irradiation step of irradiating the optical fiber with an ultraviolet ray at an illuminance of less than or equal to one tenth of an illuminance in the first irradiation step for an irradiation time of longer than or equal to 10 times an irradiation time in the first irradiation step.

Abstract: A method for manufacturing an optical fiber is a method for manufacturing an optical fiber including a glass fiber, and a coating resin layer that coats the glass fiber by being in contact with the glass fiber. The method includes a step of increasing a dissolved oxygen concentration in an ultraviolet ray curable resin composition, a step of applying the ultraviolet ray curable resin composition, in which the dissolved oxygen concentration is increased, onto the glass fiber, and a step of curing the ultraviolet ray curable resin composition by irradiating the ultraviolet ray curable resin composition that is applied onto the glass fiber with an ultraviolet ray.

Abstract: The optical fiber comprises a glass fiber comprising a core and a cladding, a primary resin layer in contact with the glass fiber and covering the glass fiber, and a secondary resin layer covering the primary resin layer, wherein the primary resin layer contains a cured product of a resin composition containing a urethane (meth)acrylate oligomer, a monomer, a photopolymerization initiator and an aromatic acid compound, a content of the aromatic acid compound is 20 ppm or more and 12000 ppm or less based on a total amount of the resin composition, and Young's modulus of the primary resin layer is 0.6 MPa or less at 23° C.±2° C.

Abstract: A method for manufacturing an optical fiber is a method for manufacturing an optical fiber including a glass fiber, and a coating resin layer that coats the glass fiber by being in contact with the glass fiber. The method includes a step of increasing a dissolved oxygen concentration in an ultraviolet ray curable resin composition, a step of applying the ultraviolet ray curable resin composition, in which the dissolved oxygen concentration is increased, onto the glass fiber, and a step of curing the ultraviolet ray curable resin composition by irradiating the ultraviolet ray curable resin composition that is applied onto the glass fiber with an ultraviolet ray.

Abstract: A method for manufacturing an optical fiber includes: a coating step of forming a first layer by applying a first ultraviolet ray curable resin composition onto a glass fiber, and then, of forming a second layer by applying a second ultraviolet ray curable resin composition onto the first layer; a first irradiation step of curing the first layer and the second layer by irradiating the first layer and the second layer with an ultraviolet ray, and of obtaining the optical fiber including a primary resin layer and a secondary resin layer; and a second irradiation step of irradiating the optical fiber with an ultraviolet ray at an illuminance of less than or equal to one tenth of an illuminance in the first irradiation step for an irradiation time of longer than or equal to 10 times an irradiation time in the first irradiation step.