Fusion splicer technology has made great progress since the days of manual feeds and mechanical cleavers. However, there is still no substitute for good clean fiber endfaces. Poor fiber cleaves in, results in poor splices out. Even cleavers have matured from the days of simple mechanical blades to sophisticated and expensive ultrasonic devices.

Over many years of teaching, I have noticed some "preconditioned" splicers who wipe the optical fiber endfaces with alcohol after the cleaving process. Even using today’s most sophisticated cleavers and splicers, this habit can produce some very poor and mechanically weak fusion splices.

This weak splice results from pad fibers and alcohol residues, which burn off during the arcing process, (in spite of a prefusion cleaning ritual first). The prefusion time/heat sequence is not always  adequate to remove the residue entirely before the final splicing plasma arc begins. With the heat of the main splicing arc, the residue rapidly burns off and gases may become trapped within the molten glass. This phenomenon can actually be seen as a "pulsating" or an expanding/compressing arc in the splicer’s microscope or video display. As the glass cools, gas may be trapped, forming a bubble or a refractive anomaly affecting the splice attenuation and scattering properties as well as the tensile strength of the splice itself.

A field splicer's best alternative is to wipe down the fiber with a good alcohol product, then cleave the fiber in a quality cleaving tool. Without wiping further, immediately place the fiber in the fusion splicer holders. If a fiber protection sleeve is used, it should be placed on the fiber prior to cleaving. This will prevent the fiber's cleaved face from being contaminated, which could result in the same inferior splice.