We demonstrate GaAs-based metamorphic lasers in the 1.3-1.55 µm telecom range grown by molecular beam epitaxy. The introduction of dopants in a compositionally graded layer is shown to significantly influence material properties, as well as having impact on the laser device design. Investigating and understanding of strain relaxation and dislocation dynamics is useful for improving material quality, performance and robustness of metamorphic devices. We demonstrate pulsed lasing up to 1.58 µm and continuous wave lasing at 1.3 µm at room temperature with low threshold currents.