A new surface emitting GaInAsP 1.3 µm LED with up to threefold enhancement in external quantum efficiency

A novel LED geometry has been developed for fibre optic systems which embodies desirable features of both surface and edge emitting LEDs. The structure can be applied to both the quaternary GaInAsP/InP and the ternary GaAlAs/GaAs systems as well as to the simple diffused junction GaAs LED. The new device, in which crystallographically selective etches are used to form facets and retroreflectors in the rear face of the LED, is theoretically capable of giving an increase in external quantum efficiency and fibre coupled power of between three and six times when compared with a butt coupled conventional surface emitter.