Modern splicers can handle both single-mode and multimode fibres, but here's what you need to know: For single-mode fibres, precision is key because of the small core size. Multimode fibres. Fusion splicing is the process of fusing or welding two fibers together usually by an electric arc. Most commonly. The three basic fiber interconnection methods are: de-matable fiber-optic connectors, mechanical splices and fusion splices. De-matable connectors are used in applications where periodic mating and de-mating is required for maintenance, testing, repairs or reconfiguration of a system.