High-Power 2.2- m Diode Lasers With Heavily Strained Active Region

High-power 2.2-μm diode lasers and their arrays were designed and fabricated. Laser heterostructures were grown using solid-source molecular beam epitaxy on GaSb substrates. The device active regions contained two 1.5% compressively strained GaInAsSb quantum wells. Heavy compressive strain in the active region ensured strong carrier confinement and high differential gain. A broadened waveguide design approach was utilized to obtain an internal optical loss below 4 cm^-1 and a threshold current density below 100 A/cm². Individual high-power lasers produced 1.6 W of continuous-wave (CW) multimode power at room temperature from a single 100-μm-wide aperture. Linear laser arrays generated more than 25 W of quasi-continuous wave output power. The device power conversion efficiencies were better than 20% in peak and above 10% at maximum output power level.