A fiber connector terminates the end of an optical fiber and enables quicker connection and disconnection than splicing. The connectors mechanically couple and align the cores of fibers so that light can pass. Most optical fiber connectors are spring-loaded: The fiber end faces of the two connectors are pressed together, resulting in a direct glass to glass or plastic to plastic, respectively, contact, avoiding any glass to air or plastic to air interfaces, which would result in higher connector losses.
The most common connector used with fiber optic cable is an ST connector. It is barrel shaped, similar to a BNC connector. A newer connector, the SC, is becoming more popular. It has a squared face and is easier to connect in a confined space.