Profiling of carrier density in semiconductor lasers via spectral analysis of side spontaneous emission

Abstract

Previous measurements of spontaneous emission from a semiconductor laser have either ignored longitudinal effects while focussing on spectral phenomena1, or have sacrificed spectral information in favour of resolving longitudinal variations2. We have, for the first lime, obtained a longitudinal carrier density profile by analyzing spontaneous emission spectra measured from the side of a laser cleaved along its length 20 μm from the ridge. Designed for reduced sensitivity to temperature fluctuations and alignment imperfections, our technique is applicable to the studs of internal operating mechanisms, including such el feels as spatial hole burning and optical damage, in both Fabry-Perot and DFB lasers.