Single-lateral-mode operation of 980-nm InGaAs-(Al)GaAs pump lasers with uncoated and coated facets

A theoretical and experimental investigation of quantum well 980-nm ridge-waveguide lasers based on InGaAs-(Al)GaAs is carried out. We quantitatively ascertain how the waveguide geometry determines the transition from single- to multilateral-mode operation. For this analysis, we used a simulator which includes the spatial hole burning and the antiguiding effects. Coated and uncoated lasers are fabricated, characterized and successfully compared with the theory in terms of threshold current and maximum single-mode output power. To the best of our knowledge, it is the first time that the experimental results are systematically compared with the theoretical predictions.