Mechanical strength of silica fiber splices after exposure to extreme temperatures

By using a combination of type-I and regenerated gratings, the mechanical strength of optical fiber splices after exposure to temperatures over 1300 C was characterized. Splice strength was found to decrease with temperature with a secondorder polynomial dependence after exposure to environments hotter than 500 C. Splices exposed to temperatures above 1300 C were 80% more fragile than non-exposed splices. The lack of optical attenuation and the narrowing distribution of breaking strengths for higher temperatures suggest surface damage mechanisms, such as hydrolysis, play a key role in weakening post-heating and that damage mechanisms dominate over strengthening induced by crack melting.