FiberHTT 100G QSFP28 LR4 integrates four transmitter and receivers into one module. In the transmitter side, the four lanes of optical data channels are optically multiplexed by the integrated optical multiplexer. In the receive side, the four lanes of optical data channels are optically de- multiplexed by the integrated optical de-multiplexer. Each data channels are recovered by a PIN photo- detector and trans-impedance amplifier, retimed. The product is designed with form factor, optical/electrical connection and digital diagnostic interface according to the QSFP28 Multi-Source Agreement (MSA) and compliant to IEEE 802.3ba.