LETTER TO THE EDITOR: High performance narrow stripe quantum-dot lasers with etched waveguide

1.3 µm range narrow stripe (8 µm) quantum-dot (QD) lasers processed in deep-mesa geometry, etched through the waveguide, demonstrate high external differential efficiency (50%) and a low threshold current density (<130 A cm−2) superior to the shallow mesa devices. This opens a new way for cost-efficient fabrication of distributed feedback and photonic crystal QD devices.