Fibre Optic Fusion Splicing – What? How? Why?
Fusion Splicing – What is it, how is it done and why is it used?
Fibre Optic Fusion splicing is the art of welding the ends of two optical fibres together using an electrical arc. The arc is precisely applied to join the two fibres together in such a way that light passing through the fibres are not scattered or reflected back by the splice. This allows the splice and region surrounding it to be as strong or stronger than the original fibre. This is usually a three stage process.
The process of fusion splicing requires both pieces of fibre to be correctly cleaned and prepared. The first step is to strip all protective coatings from the ends of both fibres, then the fibres must be cleaned with a lint-free wipe and isopropyl alcohol, until they are squeaky clean. After that, the next step is to cleave the fibre, this is the action of cutting the end of the fibre so that the endface is completely flat, this requires a special tool called a cleaver. The fusion splicer should come with both strippers and a cleave tool.
Both fibres are then placed into the fusion splicer, facing towards each other, where they become visible and magnified on-screen.
The fibres are then automatically precision aligned and then bought together through an electrical arc, where they are gently melted and permanently perfectly joined. The best quality Fusion Splicers align the inner core of the fibre, cheaper ones only align the external cladding.
The now connected fibres are then placed inside a re-enforced protective sleeve (Heat Shrink Splice Protector), this keeps the fibre protected from bending and seals it against the elements. This Splice Protector is heat sealed onto the fibre using the oven on the splicer. Most fusion splicers incorporate an oven in the design.
The speed and relatively small size of fusion splicers have made them the most popular method of joining two fibre optic cables. Alternatives to fusion splicing include using optical fibre connectors or mechanical splices both of which have higher insertion losses, lower reliability and higher return losses than fusion splicing.