We often hear about the descriptions like" LC/UPC multi mode duplex fiber optic patch cord 3 meters", or "FC/APC single mode fiber optic pigtails"," ST/PC multi mode duplex fiber optic patch cord", what do these words PC, UPC, APC mean? Here we demostrate the details.
Generally, fiber optic cable assemblies are mainly with connectors and cables, so the fiber cable assembly names have relation with the connector names, we call it LC fiber patch cord, because it is with LC fiber connector, here the words that PC, UPC, APC are related just to the fiber optic connectors and has no relationship with fiber optic cables. It is noted that PC, UPC, APC is the standard of the fiber optic connectors, PC, UPC, APC are short for: Physical Contact (PC), Ultra Physical Contact (UPC), and Angled Physical Contact (APC) respectively, they are actually the gloss style of fiber optic ferrules.
The fiber optic ferrules, unlike copper cables with copper thread in the connectors as connection media, fiber optic connectors are with these ceramic ferrules for connection, and different fiber optic connectors the ferrule size and length and polish styles will vary, ferrule is inside of the fiber optic connectors and with fiber glass from the fiber optic cable to plug into the ferrule for linking.
The different gloss of the fiber optic connector ferrules lead to the different performance of them, mainly on the back reflection (return loss). Generally, PC type is required at least 35dB return loss or higher, UPC is 55dB or higher, APC is 65dB or higher. (As we know, the higher the return loss , the better the performance). Insertion loss of them all should be less than at least 0.3dB, the lower the insertion loss, the better the performance. Single mode fiber optic cables can be with PC, UPC or APC polished connectors, however, the multimode there is no APC ones.