QSFP28 SR4 transceivers are designed for use in 100 Gbps (4 x 25 Gbps) optical links over multimode fiber. The QSFP28 SR4 integrates a four channel VCSEL array on the transmit and a four channel PIN photodiode array on the receive. Each channel can operate at 25.78 Gbps up to 100 m over OM4 Multi-mode fiber. They are compliant with the QSFP28 MSA, IEEE P802.3bm 100GBASE- SR4.