Models for Prediction of Failure Time for Optical Fibres Under Severe Aging

For optical fibres used in telecommunication networks, the failure prediction of the fibres is needed to plan maintenance operations and so ensure service reliability. Several methods of calculating the failure probability have already been reported but most of them don’t take into account the effect of temperature on fibre lifetime. On the other hand, the position, shape and the propagation of microcracks are different for every piece of fibre, because they vary with the machine used for manufacturing the fibre, composition of coating materials and the environment around the fibre. This makes difficult to develop a simple mathematical model that can predict fairly accurately the lifetime of fibres subjected to mechanical, thermal and chemical stresses. Lifetime measurement system was introduced using an experimental twisting test. Optical fibres were wounded around mandrels with different diameters and submitted to aging in hot water at different temperatures. Four models were used to estimate the time to failure. A comparison was made between experimental and model results.