While Fusion Splicing uses heat to merge the ends of two cables, Mechanical Splicing joins two or more cables with a mechanical fixture or apparatus. The ends are aligned precisely before the apparatus is applied to hold the two ends in place. A special gel is sometimes used to diminish the amount of reflection of light, although there is still a small amount of light lost after splicing, around 0.3 dB (Optical Loss is measured in dB).
Because the ends of two cables are fused together seamlessly in Fusion Splicing, there is less reflection and thus, the performance is enhanced. Fusion splicing is more often used with single mode optical fibers (SMF). There are still many companies that use multi-mode fibers, and Mechanical Splicing can be used for these companies. Mechanical Splicing is more flexible in terms of usage, it can be used both for single and multi-mode fibers. It is used by many companies for their local, short cables.
Nowadays, companies are leaning towards using single mode fibers in the future. In that case, Fusion Splicing will be more beneficial for these companies. But of course, replacing a company’s installation is a long and tedious process, so it may take a while. Until the time comes that everyone’s using single mode fibers, Mechanical Splicing will remain the only method for companies who uses multi-mode fiber.