CW room temperature operation of a diode cascade InGaAs-AlGaAs quantum well VCSEL

Vertical cavity surface emitting lasers (VCSELs) are considered as excellent candidates for optical interconnect applications due to low threshold currents, high wallplug efficiency and high-speed modulation capabilities. On the other hand, common VCSEL devices are characterized by the extremely low roundtrip gain in the cavity that requires high mirror reflectivity. Therefore, thermal rollover limits high-power applications of VCSEL structures due to internal heating. To overcome this distinct disadvantage, diode cascade VCSEL structures are proposed to reduce threshold current and heighten output power by increasing the roundtrip gain. However, the devices can only be demonstrated up to 175 K in continuous-wave (CW) operation. We present the first CW, room temperature operation of a diode cascade VCSEL at 988 nm wavelength