Fusion splicers are indispensable tools for fiber optic network installations, offering a variety of powerful splice modes to optimize performance. Each splice mode defines key parameters like arc currents, splice times, and other settings that influence the splicing process. This application note describes fundamental theory and applications behind optical fiber splicing for mechanical and, in particular, fusion spliced joints. Various fiber preparation, alignment, splicing and testing methods are discussed, as well as safety precautions and troubleshooting. Splicing. Fusion splicing is the process of fusing or welding two fibers together usually by an electric arc. Therefore, we will also touch on cost factors, risk management, and best practices in.