An approach based on strain engineering to fabricate GaSb-based type I InGaAsSb/AlGaAsSb mid-infrared laser diodes emitting at long wavelengths is presented. By incorporating a high arsenic fraction (above 2.1%) in the AlGaAsSb barriers, a tensile strain is created to compensate the compressive strain in the InGaAsSb wells. Calculations are presented to show how, while maintaining a low average strain in the active region, a low well bandgap energy and an increased valence band offset resulting in a better hole confinement can be obtained. Strain compensation is investigated experimentally by x-ray diffraction and photoluminescence. Double quantum well laser diodes were grown on GaSb by molecular-beam epitaxy. Stable room temperature pulsed lasing emission at 2.89 mum, the longest wavelength ever reported for this type of structure, was observed along with a threshold current density of 920 A/cm(2). (C) 2004 American Vacuum Society.