Polishing

Fiber optic connectors are often polished after termination to remove surface defects and to improve optical qualities such as insertion loss and backreflection.  PC and UPC connectors are polished flat (perpendicular to the length of the straight fiber), whereas APC connectors are polished on an 8^o angle from the flat.  In all these cases, the ferrule endface adopts a dome-shaped geometry that yields good mating properties in the conenctor.

See also: PC, APC, fiber optic connector, endface