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APC vs UPC: What’s the Difference?

APC vs UPC are two polish types of fiber optic connectors, aqua and blue denote a straight-through or UPC polish, while green is an angled or APC polish. The fiber optic connectors are appropriately polished to improve the performance of fiber optic connections. Therefore, choosing the appropriate type of polishing for optical connectors is crucial in fiber optic networks. There are various fiber optic connector types, such as LC, SC, ST, FC, E2000, MPO, etc. The two most common fiber polish types are UPC and APC. UPC is used in both multimode and single mode, whereas APC is typically only used for single mode. So what do UPC or APC mean? So what is the difference between them?

apc vs upc

UPC

UPC connector

UPC means “Ultra Physical Contact Connector”. It is the most common end face polish type, covering most of the fiber optic application needs. Building on the convex end face from the PC connectors, UPC utilizes extended polishing methods which creates a finer fiber surface finish. UPC connectors are polished with no angle. However, it is not exactly flat, they have a slight curvature to ensure better optical core alignment.

The straight-through connection on UPC connectors ultimately affects light reflection. Compared with a standard PC connector, this results in a lower back reflection (ORL) or reflectance value. Therefore, UPC operates with a much lower optical return loss (or ORL) thereby providing a more reliable and stable signal in digital TV, telephony, and AV. UPC connector return loss is -50 dB or lower.

APC

APC connector

APC means “Angled Physical Contact Connector”, which is also called an 8-degree angled end-face. APC adds a small 8-degree angle to the end face, light is reflected into the cladding instead of directly back to the source. Therefore, it allows for even tighter connections and smaller end-face radii. Compared with UPC, APC has a lower return loss. APC connectors can support a whopping return loss of -65dB or lower. If your application is sensitive to return loss then we suggest using APC connectors.

What the Differences of APC vs UPC

Fiber End Face

The main difference between UPC and APC connectors is the fiber end face. How the end face is shaped affects how light is reflected. UPC reflects light directly back towards the source, resulting in -50dB or lower reflections. However, by tilting the ferrule end face eight degrees, light is reflected into the cladding rather than directly back to the source. Therefore, APC can support return losses as high as -65 dB or less.

Color

APC vs UPC are the two most common fiber end face polishes, aqua and blue denote a straight-through or UPC polish, while green is an angled or APC polish. Generally speaking, best practice is to match the color of the connector to the color of the port.

Application

APC has better optical performance than UPC. APC connectors are widely deployed in service provider networks and FTTx applications. In addition, APC connectors are also commonly used in passive optical applications, such as GPONs and passive optical LANs. However, UPC connectors are less expensive. In addition, it also has low return loss, covering most of the fiber optic application needs. UPC is widely used in digital TV, telephone, telecommunication, AV Distribution, data centers, etc.

In conclusion

Deciding whether to choose UPC or APC comes down to what you need for your specific application. With applications that call for high precision, APC should be the first. But UPC is the most common. It is important to note that UPC connectors should not be mixed with APC connectors. This can damage the optical circuits in the electronics.

Bwnfiber offers a variety of custom-made fiber solutions with LC, SC, ST, FC, E2000, and MPO connectors, which come in UPC and APC polish. If you need it, please contact us: sales@bwnfiber.com.