Fusion splicing is a well-known technique to connect a fiber pair and fusion splicers have been commercially available for this process for a long time. An important feature of a fusion splice is the coupling loss that is influenced by - among other things - the mutual spotsizes of the two fibers involved. Hence, similar fibers such as standard single mode fibers can be spliced to nearly zero loss whereas dissimilar fiber pairs may give higher loss. The latter category covers the splice combinations of erbium doped fibers that are often spliced to other fiber types such as the standard single mode fiber.
We have investigated how splice loss of dissimilar fibers is influenced by fiber design with emphasis on this combination. Finally we propose a fiber design suitable for optimizing splicing capabilities of erbium doped fibers. With this design it is possible to keep fiber cutoff below 980 nm, which is of importance for practical applications, a requirement that usually conflicts with the demand for good splicing properties. An actual design, has been manufactured and splicing properties for this and the conventional design are compared.