Fusion splicing is most widely used as it provides for the lowest loss and least reflectance, as well as providing the most reliable joint. Virtually all singlemode splices are fusion. In this guide, we cover the basics of fiber optic splicing, how to perform splicing using two different methods, and finally some best practices to perform good fiber splicing. What is Fiber Optic Splicing and Why is it Needed? – #1., FTTH, FTTP, FTTM), splicing is essential for extending cables, repairing breaks, or connecting backbone and distribution lines.