8.6 A Highly Reconfigurable 40-97GS/s DAC and ADC with 40GHz AFE Bandwidth and Sub-35fJ/conv-step for 400Gb/s Coherent Optical Applications in 7nm FinFET
R. L. Nguyen, Alejandro Castrillon, A. Fan, A. Mellati, Benjamín T. Reyes, Cindra Abidin, Eivind Olsen, Faroze Ahmad, G. Hatcher, J. Chana, Laura Biolato, L. Tse, L. Wang, M. Azarmnia, Majid Davoodi, N. Campos, Ning Fan, Praveen Prabha, Qian Lu, S. Cyrusian, S. Dallaire, Stacy Ho, S. Jantzi, Tomas A. Dusatko, Wael M. Elsharkasy
Abstract
Low power digital signal processing (DSP) and optical integration have fueled the development of high-performance optical pluggable modules due to their deployment flexibility and network disaggregation. In addition, the rapid growth of new technologies such as 5G, cloud computing, IoT and AR/VR has prompted the demand for even higher data rates, requiring optical modules to scale beyond 400Gb/s while targeting the best possible tradeoff between power efficiency and reach. This necessitates more complex equalization schemes and coding techniques such as probabilistic shaping (PS) [1] and drives ever higher the specifications of analog building blocks. These requirements, as a result, constantly push the envelope of traditional analog-front-end (AFE) bandwidth and the rates of companion data converters such as DACs and ADCs to the technology limits, making it challenging to address a diversity of DSP modulation needs and oversampling rates while maintaining low power consumption. In this paper, we present an energy efficient optical transceiver fully integrated in a 400G coherent DSP chip using 4 reconfigurable 40-97GS/s 8b DACs and ADCs with a 40GHz AFE bandwidth, fabricated in a 7nm FinFET process.