What is Splicing and Fusion Splicing?

What is Splicing？

Splicing is used to permanently join two optical fibers where no additional changes are expected to be made to those fibers at that juncture. This is in contrast to connectors, which are designed to allow quick re-configuration of fiber links. There are two ways to splice optical fibers: mechanical and fusion. In a mechanical splice, the fibers are held together with ends touching inside some type of sleeve. Mechanical splices are typically used for semi-permanent connections, as in an emergency restoration or for testing and troubleshooting. Mechanical splices usually exhibit greater loss and reflection than fusion splices. In fusion splicing, the two fibers are literally welded, or fused together. This makes for a strong joint that exhibits very low loss and virtually no reflection. This paper focuses on fusion splicing, although much of what is discussed here can also be applied to mechanical splicing.

What is the fusion splicing?

Fusion splicing is performed with a piece of equipment called a fusion splicer. The fiber ends are prepared and cleaved, placed in alignment fixtures on the fusion splicer, and at the press of a button the fiber ends are heated with electrodes, brought together, and fused. There are many models of fusion splicers available, varying in features and capability, and of course cost. High-end units allow users to store separate programs or recipes where factors such as splice time and temperature can be highly customized. Such units magnify and visually display the splice, and use active core alignment to line up the fibers. Light injection technology and imaging software line up the cores so maximum light passes from one fiber to the other, ensuring minimal splice loss. Such splicing units can also provide an estimate of the splice loss. More basic fusion  splicers may employ clad alignment to line up the fibers for splicing. The fibers sit in a holder or V-groove, and are lined up “physically”, based on the outer diameter.