超高速光信号的产生和相干探测

" Broadband China" strategy is about to start, ultra high-speed optical communication technology has become the strategic choice of new revolution of science and technology. The application will focused on several promising technologies including 16QAM, Nyquist WDM, OFDM for a single channel rate up to 400 Gb/s or 1Tb/s. For single carrier polarization multiplexing modulation and coding technology, the research will be carried on multi-level advanced modulation format, and the photoelectric device bandwidth to suppress nonlinear distortion. Based on OFDM technology, we will explore the characteristics of the multi-carrier generation scheme, novel scheme to achieve high performance, high reliability of the multiple carrier. Based on Nyquist technology for WDM technology, we will study the filtering effect and its influence, propose new algorithms in coherent detection. The above three techniques have their own advantages and disadvantages, this application will aim to investigate the generation and detection mechanism, to obtain their transmission characteristics, and to solve the key technical problems in future ultra-high speed optical communication technology.

"宽带中国"战略即将启动, 超高速光通信技术的研究与拓展已然成为把握新科技革命战略选择的重中之重。本申请对实现单信道速率达到400Gb/s或1Tb/s的几种候选技术包括16QAM，Nyquist WDM、OFDM分别进行研究。对于单载波的极化复用调制码技术，主要研究多电平高级调制码，以及光电器件带宽带来的非线性畸变影响。对于基于OFDM的调制码技术，主要研究产生多子载波存在的稳定性、性能等问题，采用新方案产生高性能，高可靠性的多子载波。对于基于Nyquist WDM技术的调制码技术，研究滤波技术对其影响，提出新算法，解决相干探测的问题。以上三个技术各有其优缺点，本申请将研究它们的生成和探测机理，掌握它们的传输特性，解决关键技术问题服务于未来超高速光通信技术。

本项目提出了一种多模均衡（MMEQ）方法以抑制强滤波过程中存在的噪声和串扰，相比于带有后置滤波的恒模均衡（CMEQ）方法，MMEQ在误码率 1x10^-3处能够获得1dB的光信噪比改善度，在误码率 3.8x10^-3处能够增加32%的传输距离。在相干探测方面，实现了对经过 1120km SMF-28传输后8x112Gb/s DWDM PDM QPSK信号的外差式相干检测，且频谱效率为4bit/s/Hz，这是首次利用外差式相干检测的方式实现高频谱效率的WDM信号传输。项目采用水平和垂直天线极化复用的方式，实现了2x56Gb/s 双信道PDM QPSK信号在 80km SMF-28 和2m Q波段无线链路上的传输；项目基于多波段、多天线极化和 MIMO 技术，并结合先进的DSP技术，实现了一个创纪录的400Gbit/s 光纤无线融合系统；此外，提出了实现大容量(>100Gb/s)光纤无线融合系统的若干种不同方法，包括光极化复用和 MIMO 接收，先进的多阶调制，光多载波调制，电多载波调制，天线极化复用和多波段复用，这些方法可以有效地降低信号波特率以及对光电器件的带宽要求。