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 laser, or a gas flame, or a
tungsten filament through which
current is passed.