Optcore’s 100G QSFP28 LR4 optical transceiver combines both transmitting and receiving functions in one module. On the transmission side, it recovers, retimes, and directs four serial data streams to four laser drivers. These drivers control four electric-absorption modulated lasers (EMLs) with center wavelengths of 1296, 1300, 1305, and 1309 nm. The optical signals are then combined and sent through a single-mode fiber via a standard LC connector. On the receiving side, an integrated optical demultiplexer separates the optical data streams, which are then recovered by a PIN photodetector and transimpedance amplifier, retimed, and directed to an output driver. This module supports hot-pluggable electrical connections, features low power consumption, and includes a 2-wire serial interface.