Reliability of carbon coated optical fibers (draft)

The inert strength of carbon coated optical fibers has been observed to be less than that standard optical fibers. The fracture toughness of the carbon film and the residual stress in the film play a critical role in determining the strength of the carbon coated optical fibers. The fracture toughness and the residual stress in the film were measured for a variety of deposition conditions. A recently developed fracture mechanics model was used to predict the failure of carbon coated optical fibers. Model based strength predictions were compared to experimentally measured values. The prediction was found to be in good agreement with the measured values.