To solve this problem, the best option is to avoid direct fusion splicing between single-mode and multimode fibers. But what if the two fibers have different core sizes? Can you still splice them together using fiber fusion splicer? The short answer is yes, but there are some important things to know. Fusion splicing is the most widely used method of splicing as it provides for the lowest loss and least reflectance, as well as providing the strongest and most reliable joint between two fibers. Therefore, we will also touch on cost factors, risk management, and best practices in. Optical fibers can be joined together, such that light is efficiently transferred from one fiber to another.