Single-Mode Monolithic GaSb Vertical-Cavity Surface-Emitting Laser

We report on the fabrication and performances of an electrically-pumped GaSb monolithic VCSEL, i.e. ,a VCSEL with two epitaxial Bragg mirrors. Selective lateral etching of a tunnel junction is used to provide current and optical confinement. Laser devices with a 6 µm tunnel-junction effective diameter operate at 2.3 µm in CW up to 70 °C, with a threshold current as low as 1.9 mA at 30 °C. The laser emission is single mode with a SMSR near 25 dB and mode-hop-free electro-thermal tunability around 14 nm. This is the first demonstration of a single-mode electrically-pumped monolithic GaSb-based VCSEL.