How to distinguish UPC and APC?

The end faces are different. The polishing of UPC connector has no angle, but the end face of APC connector has an angle of 8 degrees.

Light reflection mode. The UPC connector will directly reflect any reflected light back to the light source in use, but the APC connector will reflect the reflected light into the cladding at a certain angle instead of directly reflecting it to the light source.

Return loss. APC connector provides - 65 dB return loss, and UPC provides - 50 dB. If the return loss is low, the connector can achieve better matching performance.

Connector color. This is the most obvious difference that can be seen from the surface. The UPC connector is usually blue, while the APC connector is usually green.

When selecting optical fiber jumpers, you should consider your actual application. APC connector has better performance than UPC. APC is most suitable for high-bandwidth applications and long-distance links. For example, FTTx, passive optical network (PON) and wavelength division multiplexing (WDM) are more sensitive to return loss, so APC is a better solution to provide the lowest return loss. However, a large number of APC machines will greatly increase the cost. If the requirement for return loss is not high, UPC is a better choice.