224-Gb/s PDM-16-QAM modulator and receiver based on silicon photonic integrated circuits

We demonstrate a coherent modulator and a receiver based on monolithically-integrated silicon photonic circuits, capable of modulating and detecting 224-Gb/s polarization-division-multiplexed 16-QAM. The high-degree photonic integration promises small-form-factor and low-power transceivers for future coherent systems.