When we want two fibers or fiber optic cables joint together, there are two method come to our head, installing a fiber optic connectors at the end of the optical fibers, or splicing the two optical fibers. Fiber optic cable splicing is a method that creates a permanent joint for two fibers, while fiber connector installation is used for temporary connections. There are two options for fiber optic splicing: Fiber optic cable fusion splicing and mechanical splicing. Both methods provide much lower insert loss than fiber optic connectors.
Common application for splicing is jointing cables in long outside plant cable runs where the length of the run requires more than one cable. Splicing is generally used to terminate singlemode fibers by splicing preterminated pigtails onto each fiber. It can be also used to mix numbers of different types of fiber cables like connecting a 48 fiber cables to six 8 fiber cables going to different places.
Fusion splicing provides a maximum insertion loss of 0.1 which is less than 0.5dB of mechanical splicing. Fusion splicer are available in two types that splice a single fiber or a ribbon of 12 fibers at one time. Almost all singlemode splices are fusion spliced. Mechanical splicing is most used for temporary restoration and for multimode splicing. Fusion splices are so good today that splice points may not be detectable in OTDR traces.
Fusion Splicing Process
Fusion splices are made by welding two fibers together by an electric arc of the fusion splicing machine. It can be not done in the enclosed space for safety reasons. It is suggested to done the job above the ground in a truck or trailer for a clean environment for splicing.
Fusion splicing needs the help of a special equipments which is fusion splicer to perform the splicing process. Main steps are aligning the two fibers precisely and generate a small electric arc to melt the fibers and weld them together.Splicing machine can do one fiber at a time while mass fusion splicer can do all 12 fibers in a ribbon at once.
Preparing fibers: The first step for fusion splicing is to strip, clean & cleave the fibers to be spliced. Stripping the primary buffer coating to expose the proper length of bare fiber with the fiber stripper. Clean the fiber with appropriate wipes, what you need is the fiber optic cleaning kit, Cleave the fiber using the directions appropriate to the fiber cleaver being used. Place each fiber into the guides in the fusion splicing machine and clamp it in place.
Running the splicer program: Choose the proper program according to the fiber type being spliced. The splicer would show the fibers being spliced on a video screen. The fiber ends will be inspected for proper cleavers and bad ones will be rejected for a second time cleaving. The fibers will be moved into position, prefused to remove any dirt on the fiber ends and preheat the fibers for splicing. The fibers will be aligned using the core alignment method used on that splicer. Then the fibers will be fused by an automatic arc cycle that heats them in an electric arc and feeds the
fibers together at a controlled rate.
Ribbon fusion splicing: Each ribbon is stripped, cleaved and spliced as a unit. Special tools are needed to strip the fiber ribbon, usually heating it first, then cleave all fibers at once. Many tools place the ribbon in a carrier that supports and aligns it through stripping, cleaving and splicing. Consult both cable and splicer manufacturers to ensure you have the proper directions.
Fusion splicing pigtail is another typical application for fiber optic splicing. By this method, a fiber optic patch cord is cut into two pigtails with connectors attached. The fibers are cleaved and welded together with a fusion splicer, which is considered to be the fastest and highest-quality method of fiber connector installation.