RIN suppressed multimode 850-nm VCSEL for 56-Gbps 16-QAM OFDM and 22-Gbps PAM-4 transmission

A multimode 850-nm VCSEL with its relative-intensive-noise suppressed to -145 dBc/Hz is employed for directly encoded 56-Gbps 16-QAM OFDM and 22-Gbps PAM-4 transmissions with corresponding BERs of 3.2×10<sup>-3</sup> and 1.9×10<sup>-10</sup>, respectively.