A cleave in an optical fiber is a deliberate, controlled break, intended to create a perfectly flat endface, perpendicular to the longitudinal axis of the fiber. The process of cleaving an optical fiber forms one of the steps in the preparation for a fiber splice operation regardless of the subsequent splice being a fusion splice or a mechanical splice; the other steps in the preparation being those of stripping and fiber alignment. A good cleave is required for a successful low loss splice of an optical fiber, often it is the case that fibers spliced by identical methods tend to have different losses, this difference can often be attributed to the quality of their initial cleaves.