Splicing is a “permanent” connection between two fibre cores, and is the preferred method for terminating. There are two types of splices, fusion and mechanical.
Fusion Splices are made by “welding” the two fibers together by an electric arc. Field fusion splicing is usually done above ground in a truck or trailer set up for the purpose.
Mechanical Splices are alignment gadgets that hold the ends of two fibers together with some index matching gel or glue between them. There are a number of types of mechanical splices, like little glass tubes or V-shaped metal clamps.