Patent ID: 7978948

Claim:
An optical fiber comprising: a colored optical fiber coated with at least three layers of coating resin of ultraviolet cured resin, the three layers comprising a primary layer, secondary layer and outermost colored layer, wherein the secondary layer has elasticity modulus of 500 MPa or larger and the outermost colored layer has elasticity modulus of 1050 MPa or larger, glass transition temperature of 85° C. or higher and is made of color resin, and an extraction rate of said coating resin is 1.5 mass percent or below when, an unfinished colored optical fiber with the primary and secondary layers before being coated with the colored layer, is immersed in water which is heated to 60° C. for 168 hours, and the extraction rate of said coating resin when said colored optical fiber coated with the primary, secondary and colored layers is immersed in water which is heated to 60° C. for 168 hours is lower than the extraction rate of said coating resin when, said unfinished colored optical fiber with the primary and secondary layers before being coated with the colored layer, is immersed in water which is heated to 60° C. for 168 hours.