Cutting Cables & Cleaving Fibers

An important part of installing fiber optic cables is cutting those cables-and the in individual fibers within them. And that means cutting very different processes to use: cutting and cleaving.
Cutting, in these terms, applies to the cable. To cut the cable, first carefully remove the cable jacket with a cable slitter. Next, gather the Kevlar into a "rope," then, using a Kevlar cutter, snip the rope, leaving enough to terminate into any required stress relief lugs. This will expose the loose buffer tubes or tight buffered fibers.
At this point, cut the inner central strength member with the appropriate tool (usually regular sidecutters) and secure it in its lug. (Depending on manufacturer -specs, the Kevlar and the central strength member may share the same lug.)
If there are loose buffer tubes in the cable, carefully remove them with a buffer tube cutter. Tight buffers can be stripped off using a jacket stripper to reveal the coated fibers. A coating stripper sized for the job (the coating can be from 250 to 900 microns thick) then brings the fibers down to bare glass. Finally, the bare fiber is cleaned using just one firm wipe of an alcohol-saturated pad.
Cleaving-scoring and cutting- is the process used on the individual fibers. Remember, optical fibers are glass, and simply cutting them with a a pair of side cutters would ruin the surface. In fact, cleaving fibers is much like cutting heavier glass.
Start by using the sharp blade of a scribe or cleaver (a cleaver is generally preferable) to put a surface defect on the fiber. Next pull carefully to allow a crack to propagate across the fiber. In most cases, fiber ends should be close as possible to perpendicular to the fiber axis . Some systems, however, require fibers to be cleaved at a angle - usually about 8 degrees off of perpendicular - which is the best accomplished with special angled cleavers.
Before fitting the fibers with splices or connectors, check them (and polished connector ferrules) for possible defects using a microscope with a stage modified to hold the fiber or connector in the field of view. Cleaved fiber are usually viewed from the side, to see breakover and lip. Connectors are typically viewed end-on or at a small angle to find polishing defects such as scratches.



Source:www.elec-toolbox.com/communications/classifications/fiber/fiber.htm