SINGLE MODE OPTICAL FIBER, OPTICAL FIBER CABLE, OPTICAL FIBER CORD AND SERVICE LIFE GUARANTEEING METHOD OF OPTICAL FIBER

摘要

PROBLEM TO BE SOLVED: To provide a single mode optical fiber capable of detecting whether or not the fiber is layed appropriately by utilizing the increase in transmission loss when the fiber is bent to its limit.;SOLUTION: In the single mode optical fiber having a cut-off wavelength in which it practically becomes single mode transmission in a wavelength 1.31μm band, a ratio refractive index difference of the core with respect to the clad is adjusted so that bent loss becomes greater than a detection limit value when bending is applied having a radius that is smaller than the optical fiber limit bending radius which is obtained from the relationship between the bending radius being applied to the optical fiber and the frequency of failure generated after a prescribed service life in the bent condition with the radius.;COPYRIGHT: (C)2006,JPO&NCIPI