Optical components manufacturers II‐VI introduced its 56 Gb/s PAM4 VCSEL arrays for 400 gigabit Ethernet (GbE) short reach transceivers and active optical cables (AOCs) deployed in datacenters. The availability of Ethernet equipment with greater than 12 Tb/s of switching capacity enables hyperscale datacenters to accelerate the migration from 100 to 400 GbE transmission. II-VI’s 8-element VCSEL arrays can be modulated at 56 Gb/s using 4-level pulse amplitude modulation (PAM4) to achieve a combined 400 Gb/s over short reach multimode links. ...