APC Connector is a type of fiber connector that minimizes backreflection due to a 5° to 15° angle-polish applied to end faces. Like illustrated in the following picture. Because of the angle, the reflected light does not stay in the fiber core but instead leaks out into the cladding. Angle-polished. Among the emerging preferences, LC/APC and MU/APC connectors stand out for their reduced size compared to larger counterparts like SC/APC, positioning them as the dominant choice in today's evolving network infrastructure. APC Interconnect Type Products: Problems and Solutions End-Face Angle. Connectors with angle polished (APC) finishes are a very popular choice in the market today.