OP-QSFP28-ER4 optical transceiver module designed for use in 100 Gigabit Ethernet links over single fiber, up to 40km transmission distance. It is compliant with the QSFP28 MSA and IEEE 802.3ba. The module transmitter section use cooled LAN WDM EA-DFB laser and receiver section use high sensitivity APD.

It converts 4 channels of 25Gb/s electrical data to 4 channels of LAN WDM optical signals and then multiplex them into a single channel of 100Gb/s optical transmission.

On the receiver side, the module de-multiplex a 100Gb/s optical input into 4 channels of LAN WDM optical signals and then converts them to 4 channels of output electrical data. The central wavelengths of the 4 LAN WDM channels are 1295.56, 1300.05, 1304.58 and 1309.1 nm.

The electrical signals are processed by a 4-channel Clock and Data Recovery (CDR) IC that reshapes and reduces the jitter of each electrical signal. And the EML laser driver IC converts the electrical signals to an optical signal that is transmitted from one of the 4 cooled EML lasers which are packaged in the Transmitter Optical Sub-Assembly (TOSA). Each laser launches the optical signal in specific wavelength specified in IEEE 802.3ba 100GBASE-ER4 requirements. These 4-lane optical signals will be optically multiplexed into a single fiber by a 4-to-1 optical WDM MUX.  Each channel optical output power is maintained constantly by an automatic power control (APC) circuit. The transmitter output can be turned off by TX_DIS hardware signal and/or 2-wire serial interface.

The Receiver side receives 4-lane LAN WDM optical signals. These optical signals are de-multiplexed by a 1-to-4 optical DEMUX and is fed into the 4 receivers that are packaged into the Receiver Optical Sub-Assembly (ROSA). Each channel optical signal convert to an electrical signal. The regenerated electrical signals are re-timed and de-jittered and amplified by the RX portion of the 4-channel CDR.  The re-timed 4-lane output electrical signals are compliant with CEI-28G-VSR interface requirements. In addition, each received optical signal is monitored by the DOM section. The monitored value is reported through the 2-wire serial interface. If the received optical signal is weaker than the threshold level, RX_LOS hardware alarm will be triggered.