Single-mode MBE-grown 1550 nm wafer-fused VCSELs for high-speed PAM4 data transmission

We study high-power high bit rate single-mode 1550 nm vertical-cavity surface-emitting lasers fabricated using wafer-fusion. The optical cavity was grown on an InP wafer. The two undoped AlGaAs/GaAs distributed Bragg reflectors on two separate GaAs wafers. All three heterostructures were grown by molecular beam epitaxy. The active region is based on thin tensile-strained InGaAs/InAIGaAs quantum wells. Intracavity contacts were used for current injection. Buried tunnel junctions based on InAIGaAs confined current and optical radiation.