Superluminescent diodes are optoelectronic semiconductor devices which emit broadband optical radiation based on superluminescence. In terms of their construction, they are similar to laser diodes, containing an electrically driven p–n junction and an optical waveguide. Importantly, however, SLDs are made to avoid any optical feedback by reflections, so that no laser action can occur.
The mechanism of SLD emission is the same as semiconductor laser (LD) and light emitting diode (LED). Emission occurs by flowing forward current to a p-n junction. When a power supply is connected to the p-layer positive and the n-layer negative, electrons enter from the n-side and holes from the p-side. When the two meet at the junction, an electron drops into a hole and light is emitted.
