光电混合型高速高精度数模转换器的关键技术研究

High speed Analog-to-Digital converter (ADC) and Digital-to-Analog converter(DAC) are the key components of high speed optical transmissionsystems. Sampling rate of the ADC/DAC in current100Gb/s optical transmission systemis up to 65GS/s which is approaching the limit of electronic systems. It becomes a hot topic on how to design higher speed and resolution ADC/DAC to meet the demand of future optical systems. One important method is to introduce photonic techniques to break the bottleneck and develop electronic-photonic hybrid ADC/DAC. However, current research is most focused on electronic-photonic ADC while DAC is rarely studied. This project proposes a electronic-photonic DAC which implements the MUX unit and the DAC core in optical domain and electronic domain respectively. Photonic techniques are used to overcome the difficulties of generating and aligning high speed electronic bit streams in electronic domain. electronic-photonic DAC has the merits of high speed, high resolution and low cost, and has good potential in future applications. This project studiesthe key techniques in the new architecturesuch as the strategy of the generating and aligning the high speed bit streams in photonic domain, the design of DAC core, the circuit design of photonic interfaces and wide bandwidth matching.

高速模数转换器（ADC）/数模转换器（DAC）是高速光传输系统所必需的关键器件。当前，100Gb/s光传输系统已成为主流，对ADC/DAC的需求达到了65GS/s，已接近电子系统抖动和带宽性能的极限。如何设计更高速度和精度的ADC/DAC以应对未来更高速的光传输系统需求，成为目前的研究热点。一个重要的思路是引入光技术，设计光电混合型ADC/DAC以突破电子技术瓶颈。目前已有研究多集中在光电混合型ADC上，对光电混合型DAC研究较少。本项目首次提出一种光电混合型DAC，将DAC中多路复用单元、DAC核心电路分别在光域和电域中实现，利用光技术克服高速码流的产生和对齐等问题，实现更高速度和精度。光电混合型DAC具有高速、高精度、低成本等优点，具有重要的研究意义和应用前景。本项目围绕这种新型架构，对高速码流产生与对齐方案、DAC核心电路设计、光电接口电路的设计和宽带匹配等关键技术进行了研究。

本项目深入研究了光电混合数模混合器的实现方案，从DAC的基本原理出发，分析了DAC设计的关键技术，利用了光域信号高速的优势，在光域中实现高速信号的生成和同步，利用电域进行数模转换精度高的优点,在电域中实现数模转换。设计了40GS/s 8bit光电混合数模转换器及光电转换接口芯片，芯片仿真结果满足项目需求;实验验证了光域生成高速信号，成功生成高质量的56Gbps信号；设计了一款32GS/s 6bit DAC芯片，该芯片测试性能良好，并将该芯片在直调直检系统中进行了验证。光电混合型DAC具有高速、高精度、低成本等优点，具有重要的研究意义和应用前景。