The QSFP28 PSM4 is a Four-Channel, Pluggable, Parallel, Fiber-Optic QSFP28 Transceiver for 100G Ethernet  Applications. The QSFP28 full-duplex optical module offers 4 independent transmit and receive channels, each capable of 26Gbps operation for an aggregate data rate of 104Gbps 2km using single mode fiber. These modules are designed to operate over single mode fiber systems using  DFB laser array. An optical fiber ribbon cable with an MPO/MTPTM connector can be plugged into the QSFP28 module receptacle. QSFP28 PSM4 is one kind of parallel transceiver which provides increased port density and total system cost savings.

The OFQ212G10C-FP4 QSFP28 optical transceiver is intended for up to 10km reach service with four-lane 25.78125G data rate. It is based on 3.3V DC power supply and operates in the commercial temperature range. It is compliant with QSFP MSA 、SFF-8436 、SFF-8636 and PSM4 MSA. Digital diagnostic functions are available via  I2C interface，and the control functions can be  achieved by LVTTL interfaces on the host，mainly including Module Select(ModSelL)、Module Reset(ResetL)、 Low Power Mode(LPMode). The transceiver incorporates a four-laser array which is usually DFB 、four-PIN diode array 、a high performance CDR integrated four drivers and TIAs IC separately. The differential AC coupled Tx and Rx data interfaces are CML compatible.