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2955 Kerner Blvd. San Rafael, CA 94901-5533 Tel 800-234-7858 Fax 415-453-9956 www.BerkeleyNucleonics.com

Berkeley Nucleonics Corporation

Comparing Fiber Optic Connectors for Various Applications

What is the difference between UPC and APC fiber optic connectors ?

By definition, the above are acronyms for the following:UPC Ultra Physical Contact

APC Angled Physical Contact

The typical reason for the APC connector is a lower lightwave reflectance. Nominal specification areas follows:-55 dB for UPC connectors vs -65 dB for APC connectors

This makes APC cables ideal for system components that are light-sensitive. The design of an APCconnector results in less insertion loss (0.2 dB) at the interface.PC, UPC and APC fiber optic patch cable assemblies:

Usually we hear about 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 jumper". What dothese words PC, UPC, APC mean? Here we give explanations.

As we know, fiber optic cable assemblies are mainly with connectors and cables, so the fiber cableassembly names is related to the connector names, we call it LC fiber patch cord, because it is withLC fiber connector, here the words PC, UPC, APC also are related only to the fiber optic connectorsand has nothing to do with fiber optic cables.

We have known that PC, UPC, APC is standard of the fiber optic connectors, PC, UPC, APC are

short for:Physical Contact (PC)Ultra Physical Contact (UPC)

Angled Physical Contact (APC)

These are actually the polish style of fiber optic ferrules. Unlike copper cables with copper thread inthe connectors as connection media, fiber optic connectors are with these ceramic ferrules forconnection, and different fiber optic connectors the ferrule size and length and polish styles aredifferent. Such ferrules are inside the fiber optic connectors.

The different polish of the fiber optic connector ferrules result in different performance, mainly on the

back reflection (return loss). Generally, PC type is required to have at least 40dB return loss orhigher, UPC is 50dB or higher, APC is 60dB or higher. (The higher the return loss the better theperformance of the mating of two connectors). Insertion loss of them all should be less than 0.3dB,with the lower the insertion loss being the better the performance.

Single mode fiber optic cables can be with PC, UPC or APC polished connectors, while multimodefibers are not made with APC connectors.

Contact the factory for names of cable and connector manufacturers in your area.