Strength of silica fibers in various moisture conditions

The reliability and the expected lifetime of silica fibers are closely related to the chemical action of water molecules on silica. Strength and dynamic fatigue behaviour of silica optical fibers were measured in very dry atmosphere. Bare and coated fibers were compared to characterize the influence of the polymer. Dynamic mechanical tests were implemented using a two point bending set-up. The stress corrosion susceptibility parameter has been evaluated. At the higher stressing rate the slope of the dynamic fatigue curve was found to drop significantly. This behaviour is usually observed for specially damaged fibers tested at very high speed.