An optical 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 light can pass. Better connectors lose very little light due to reflection or misalignment of the fibers. In all, about 100 different types of fiber optic connectors have been introduced to the market.

Source: https://en.wikipedia.org/wiki/Optical_fiber_connector#MT-RJ