Superluminescent diode

A superluminescent diode ( SLED or SLD ) is a component of optoelectronics and corresponds in structure to a laser diode but without resonator. Its radiation is based on the so-called amplified spontaneous emission, and combines the brightness of the laser diode and the low coherence of light emitting diodes, which is synonymous with a greater optical range of the emitted radiation.

The superluminescent diode has been developed in 1986 by Gerard A. Alphonse in the Radio Corporation of America (RCA Labs). It serves as a light source in fiber-optic gyroscopes, and, inter alia, in the field of optical coherence tomography.

Construction

SLED such as laser diodes based on a pn junction and are operated in the direction of passage. The emitted mean wavelength based on the band gap and can be obtained by selection of different semiconductor materials such as indium arsenide ( InAs ), indium gallium arsenide (InGaAs ) or indium phosphide (InP ) be affected. In contrast to laser diode SLEDs have no resonator which an optical feedback means is mirrors. In SLED optical resonance is avoided due to the design and additionally applied anti-reflective coating. Superluminescent diodes provide optical amplifier is no input signal, which generated by spontaneous emission light by stimulated emission inside the SLED, which acts as a waveguide optically amplify and radiate. This function is eponymous for the component.