2Serial-2Parallel Optical DAC for High-Resolution Photonic-Efficient Energy-Efficient 4|16|64|256 QAM

Next upgrade to QAM256 poses formidable barriers in terms of attainable performance and energy-efficiency of DAC driver + MZM based Transmitters (Tx). A promising alternative, potentially changing the ‘rules of the game’ is optical DACs (oDAC). In previous work, we proposed a PAM4-driven optical Tx generating up to 256QAM. Here we introduce a novel oDAC parallelizing a pair of optimized 2-segment MZMs, remarkably fed by 4 uncoupled NRZ signals. Based on a pair of IQ-nested new oDACs, the resulting DAC-less QAM Tx is fed by 8 uncoupled NRZ drivers. The energy efficiency, photonic efficiency and resolution of the flexible oDAC and QAM Tx are at their utmost.