Investigation of mechanisms of multimode emission from double-heterostructure AlGaAs injection lasers with narrow stripe contacts

An investigation was made of the spectral characteristics of planar stripe (contact width 6–8 μ) lasers made of AlGaAs heterostructures. The steady-state emission spectrum could be of multimode type because of the high level of spontaneous emission in the lasing mode. The spectrum then became narrower on increase in the power and in the limit changed to the single-mode form. However, in the presence of self-modulation processes the multimode nature of the emission spectrum could be explained by a theory of transient effects and in this case the width of the spectrum increased on increase in the power.