Highly efficient GaInAs/(Al)GaAs quantum-dot lasers based on a single active layer versus 980 nm high-power quantum-well lasers

Highly efficient 980 nm GaInAs/(Al)GaAs quantum-dot (QD) and quantum-well (QW) lasers based on a single active layer have been fabricated and compared in view of high-power applications. QD lasers show a significantly reduced temperature shift of the emission wavelength and achieve external quantum efficiencies of 80% (>1 W/A for 1-mm-long devices). For longer cavity lengths (>2.5 mm), QD lasers show lower threshold current densities than QW lasers. Threshold current densities as low as 54 A/cm2 are reached.