Cleaving an optical Fiber is making a controlled break of the fiber to produce a smooth end prior to Splicing or terminating. This is necessary because in order for Light signals to transmit properly when fibers are spliced or connected the fibers require End Face preparation.
Cleaving is also called the “scribe-and-break” method. Well done fiber Cleaving leaves a mirror like finish, poor Fiber Cleaving causes defects like hackles and lips.
A nick is made in the fiber and the fiber is then pulled or flexed to cause a clean break.