OPTICAL FIBER CORE

PURPOSE:To improve and stabilize the dependency of a transmission characteristic on temp. and mechanical characteristic by covering a thermosetting resin reinforced with carbon fibers or arom. polyamide fibers on the outside of an optical fiber strand at a specific lamination angle or below. CONSTITUTION:A primary layer 2 and a buffer layer 3 are provided on an optical fiber 1, and in the stage of forming a secondary coverong layer 4 thereon, carbon fibers or arom. polyamide fibers 6 from bobbins 8 are passed through a tank 7 contg. the liquid of a thermosetting resin such as an unsatd. polyester resin, epoxy resin or the like toward the direction of the fiber 1 to laminte the reinforced resin contg. 40-85% said reinforcing fibers at