Electrically-pumped VCSELs using type-II quantum wells for the mid-infrared

We demonstrate the extension of the wavelength range of InP- and GaSb-based buried tunnel junction VCSELs using type-II quantum wells. The InP-based devices emit at 2.5 μm and operate in continuous-wave (CW) up to 20°C, with a maximum single-mode output power above 500 μW. They exhibit a continuous electro-thermal tuning range of 5.2 nm. The GaSb-based devices emit up to 4 μm and operate in CW and pulsed mode until -7°C and 45°C, respectively. The maximum single-mode CW output power is 175 μW. A mode-hop free electro-thermal tuning of ~19 nm is achieved. These VCSELs are highly promising for gas sensing applications.