Tapered InGaAs/GaAs MWQ lasers with carbon modulation-doping and reduced filamentation

Highly localised carbon doping is demonstrated within the active region of strained InGaAs/GaAs MQW lasers. As predicted by numerical beam propagation simulations, the smaller linewidth enhancement factor arising from the combination of strain and p-doping leads to reduced filamentation in tapered laser structures, as compared to devices fabricated from otherwise identical epilayer structure containing undoped active regions.