Axial strain in optical-fiber cable manufacture and duct installation

In a tightly-packaged helically wound cable axial strain in both multimode and monomode optical fibers was measured at all manufacturing stages. The results were combined with incremental strains measured for a standard installation process. The results show that on average fiber remained in compression of 0.10 percent after installation and thus would suffer no static fatigue. Some processess gave rise to variations about this average to give a peak strain of 0.09 percent over short lengths of cable, but even this is well inside the limit below which proof-tested fibers should survive for 20 years.