Fusion splice

Fusion splicing is the act of joining two optical fibers end-to-end using heat. The goal is to fuse the two fibers together in such a way that light passing through the fibers is not scattered or reflected back by the splice, and so that the splice and the region surrounding it are almost as strong as the virgin fiber itself. The source of heat is usually an electric arc, but can also be a tungsten filament through which current is passed.
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In fiber optics, a splice created by localized heating of the ends of the two fibers to be joined. Note: A properly made fusion splice results in a continuous length of material with minimal discontinuities at the splice.