A Light emitting Diode (LED) is a Semiconductor device that emits light when stimulated by an electrical current. They are used in transmitters for Multimode Fiber links.

The basic types of LEDs used for Fiber Optics are the surface-emitting LED (SLED), the edge-emitting LED (ELED) and the superluminescent diode (SLD).

LEDs convert electrical signals into light signals SO that they may be passed through the fiber optic cable. Unlike regular incandescent lights, LEDs stay relatively cool.

They are small and emit a lot of light making them perfect for Multimode Fiber optic applications. They are easy to use, last longer and cost less then lasers and are also more reliable.

LEDs are used as status and continuity indicators, as well as for light sources for small applications and also for signs like traffic signals, emergency vehicle lights and airport signs. LEDs are used where night vision must be maintained.

LEDs are also used to transmit Digital information as is the case with remote controls, fiber optic applications, movement sensors and displaying messages in a DOT matrix.