Splicing process factors exist for mechanical (butt-spliced) joints, including fiber-end
separation, fiber-end angle and fresnel reflection.
The fiber coating can be removed by a number of techniques such as a mechanical stripping tool, thermal stripping equipment, or chemically. For typical acrylate-coated fibers, mechanical stripping is recommended because it is fast, safe, inexpensive and creates a well-defined coating termination.
It is important to note that, when mechanically or thermally stripping fibers, care must be taken to avoid damaging the fiber surface. The stripping tool should be the proper size and designed for the fiber and coating combination being stripped. Also, to avoid damage to the glass surface, no more than two inches of the coating should be stripped at one time. Chemicals that soften the acrylate coatings are slower and create a poorly defined coating termination.
Additionally, residual action of chemicals may cause the acrylate coating to soften and degrade long after the splice has been packaged, potentially causing splice failure. For this reason, all fibers exposed to the chemical solvent must be thoroughly cleaned after stripping.
Any acrylate coating residue that remains after stripping should be removed from the bare fiber surface. A clean, lint-free cotton (or alcohol-soaked) pad gently pulled over the fiber surface works well for most mechanically stripped fibers with acrylate coatings. It is important to handle bare fibers as little as possible from this point until the splice is complete. Taking this precaution will minimize the chance of contaminating the fibers with dust or body oils, which may contribute to higher splice losses and lower tensile strengths. It also is important to complete the remaining splicing process as quickly as possible, since delays will expose the fiber to additional airborne contaminants. Failure to utilize careful cleaning practices may cause the glass surface to become abraded leading to lower splice strength.
Since the primary attribute affecting single fusion splicing is the end angle, proper fiber-end preparation is a
fundamental step in obtaining an acceptable fusion splice. Fiber-end angle requirements vary slightly from user to user, depending on the splice loss requirements and the cleavers used. However, in general, end angles less than two degrees yield acceptable field fusion splices (typical end angles with well-controlled cleavers are around one-half degree)