Mechanical reliability of optical fiber with sputtered metallization for hermetic terminations.

The long term mechanical reliability of optical fiber with sputtered metallization for hermetic terminations in optical devices is improved by the reduction in static fatigue of the fiber due to the hermeticity of the metallic coating itself. Strength and fatigue properties of these fibers have been evaluated by dynamic fatigue testing. Although such coatings degrade initial fiber strength, the resulting hermetic (or quasi-hermetic) sealing of the fiber surface reduces the fatigue rate. Comparative results for similar fiber not hermetically protected show a greater fatigue rate and give support to the long disputed dependence of stress-crack growth rate on crack size.