Silicon-on-sapphire CMOS for improved VCSEL/CMOS optoelectronic interconnects

The technology of vertical-cavity surface-emitting lasers (VCSELs) as used in optoelectronic interconnects is becoming quite mature and is finding many fiber and free-space interconnect applications. The 850-nm GaAs-AlGaAs quantum well VCSEL technology is the most mature and most widely employed for fiber interconnects. Unfortunately, flip-chip bonded 850-nm VCSELs are sandwiched between the opaque complementary metal oxide semiconductor (CMOS) silicon and optoelectronic GaAs substrates, requiring GaAs substrate removal or some other additional measures to achieve successful interconnects. We discuss new Si-on-sapphire CMOS applications