It’s known to us that whenever a connector is installed on the end of fiber, loss cannot be avoided. Some of this light loss is reflected directly back down the fiber towards the light source that generated it. These back reflections, or Optical Return Loss (ORL), will damage the Laser Light Sources and also disrupt the transmitted signal. Therefore, various polish profiles are used, but it depends on the type of fiber and the application. Generally speaking, a typical hand polished connector will measure at 30dB. And there are several common polishing types: PC, UPC and APC. In order to reduce the back reflection of connectors, they can be polished by PC or UPC. When a even less back reflection is needed, an APC(Angled Physical Contact) polish might be necessary. In addition, fiber optic connectors usually can be divided according to the polishing types. The following picture is show the different connect of the mentioned polishing types.
