106-fJ/(bit·km) 2-km OFDM OM4 MMF transmissions for energy efficient optical interconnects

Employing high-performance 850-nm VCSELs with oxide-relief and Zn-diffusion structures, we demonstrate 17.8-Gbps 2-km OM4 fiber transmissions. Meanwhile, ultra-low EDDR of 106 fJ/(bit·km) with bias current as low as 1.9 mA is achieved.