Optical unit null for optical fiber compound overhead earthwire

摘要

PURPOSE:To reduce bending distortion in optical fibers to thereby extend service life by providing a constitution so that the stranded pitch and stranded layer core radius of the optical fiber, groove pitch of spacer, the layer core radius and the radius of the optical fiber may satisfy a specified relation. CONSTITUTION:A relation of 300=Pf=2pi(625rf)1/2 and 500=Ps=100pi ru(ri+rf)1/2 is satisfied, where Pf: is the stranded pitch of optical fiber, rf: the stranded layer core radius of optical fiber, Ps: the pitch of grooves 2 of a spacer 1, ru: the radius of layer core 4 of the optical unit, and ri: the radius of the optical fiber. With this constitution, bending distortion in the optical fiber is reduced and thereby the long reliability of optical fiber cable 3 is enhanced.