Five stacked layers of InAs quantum dots (QDs) embedded in quaternary InGaAsP were grown on (100) InP substrate to form a laser diode. Two methods were used to achieve tuning: changing the laser cavity length or varying the temperature. Stimulated emission between ∼1.51 and ∼1.64 μm was observed depending on the cavity length and the QD barrier height. The threshold current density was decreased for longer cavities to a value as low as 49 A/cm 2 at 77 K. The relation between temperature and lasing peak wavelength was measured to be ∼0.21 nm/K leading to room temperature lasing at ∼1.61 μm.