APC connector is the most widely used fiber connector type today. “APC” stands for Angled Physical Connect. The singlemode fiber connectors you likely encounter the most feature a blue connector body, but if you're working with any passive optical networks (PONs), carrier networks or large cloud/colo or hyperscale data centers, you may encounter singlemode fiber connectors with a green connector body –. APC connector is the most widely used fiber connector type today. In simple terms: The angled end-face directs reflected light away from the source, reducing signal reflection. This design significantly. To put it simply, PC, UPC, and APC refer to the polish styles of the ferrules inside the fiber optic connectors, just as the following figure shows.