Solid state light source for emitting light over a broad spectral band

摘要

A solid state light source comprising a monolithic light emitter diode structure having a graded bandgap active region 8 the thickness of which is graded between two materials 9, 11, the said materials having differing center wavelengths of light emission, such that the source is capable of emitting light at wavelengths L1, L2 spaced over the whole spectral width between the wavelengths exhibited by the said two materials. This can enable the light source to be used in optical fibre devices where it can provide on alternative to the filament lamp source and thus give an increased reliability in use.