We demonstrate a 2 × 100 Gb/s transmitter and a 4 × 100 Gb/s receiver as the key components for multi-100-GbE and 400-GbE optical interfaces in future intradata center networks. Compared to other approaches, the two devices can provide significant advantages in terms of number of components, simplicity, footprint, and cost, as they are capable of serial operation with nonreturn-to-zero on-off keying format directly at 100 Gb/s. The transmitter is based on the monolithic integration of a multimode interference coupler with two Mach-Zehnder modulators on an electro-optic polymer chip, and the hybrid integration of this chip with an InP laser diode and two multiplexing and driving circuits. The receiver on the other hand is based on the hybrid integration of a quad array of InP photodiodes with two demultiplexing circuits. Combining the two devices, we evaluate their transmission performance over standard single-mode fibers without dispersion compensation and achieve a BER of 10 −10 after 1000 m and a BER below 10 −8 after 1625 m at 2 × 80 Gb/s, as well as a BER below 10 −7 after 1000 m at 2 × 100 Gb/s. Future plans including the development of tunable 100 GbE interfaces for optical circuitswitched domains inside data center networks are also discussed.