40Gb/s/λ WDM-PON调制及相干数字接收机关键技术研究

Wavelength division multiplexed passive optical network (WDM-PON) system with 40-Gb/s transmission rates per channel and large coverage distance is an important development trends of future optical access technology. Because of the defects of system structural complexity and unable to dynamical adjusting, it is difficult that the existing 40-Gb/s rates optical transmission technology is used in WDM-PON system. Coherent optical receiver and electrical domains equalization, can effectively increase the coverage distance and reduce system structural complexity, is an important 40-Gb/s per channel WDM-PON transport solution. The research work mainly include: (1) Research and propose the modulation pattern and generation scheme suitable for high-speed WDM-PON; (2) Research the impact and constraint law among the clock synchronization, dispersion and noise equalization, et al, then propose the effective signal impairment equalization digital processing algorithms that can effectively compensate for signal impairments caused by fiber dispersion, the channel noises, nonlinear effects, and propose effective parallel processing mechanism; (3) Establish the simulation platform and experimental system of a loopback structure 40Gb/s/λ WDM-PON uplink optical transmission. Based on the innovative theoretical studies and scientific experiment works, we hope to achieve innovation and technological breakthroughs on modulation pattern and generation scheme, digital de-damage mechanism, the impact and constraint law among the different function algorithms, the joint parallel processing algorithm and system simulation and experiment. The research achievement can significantly reduce the demand on the processing speed of electronic device, and can provide the core technology foundation for the practical application of the 40Gb/s/λ WDM-PON optical transmission.

大覆盖范围40Gb/s/λ速率WDM-PON是未来光接入技术的重要发展方向。已有40Gb/s光传输技术因其结构复杂、固定等不足难以满足WDM-PON传输距离、上行波长灵活可变以及低成本等的需求。利用相干光接收及电域去损伤技术能够有效提高WDM-PON覆盖灵活性并降低系统结构复杂性，是40Gb/s WDM-PON的重要传输解决方案。本项目主要研究内容包括：(1)研究提出适用于高速WDM-PON的调制码型及产生方案；(2)研究时钟同步、色散与噪声均衡等相互间的影响与制约规律，提出有效补偿光纤色散、信道噪声、非线性效应等对信号损伤的数字处理算法及并行处理机制；(3)建立环回大覆盖40Gb/s/λ WDM-PON上行光传输系统的仿真平台和实验系统。通过以上理论研究和实验工作，拟在调制码型及产生方案、数字去损伤机理、各功能算法相互作用和影响规律、并行处理算法和系统仿真与实验等方面实现创新和技术突破。

WDM-PON因具有带宽容量大、可分波长承载业务、支持平滑无缝演进等优点，是下一代PON的最优演进方案之一。随着接入网带宽需求的进一步提高，单波长40Gb/s 是WDM-PON系统的重要发展方向。已有40Gb/s光传输技术因具有结构复杂、成本高等不足，难以满足WDM-PON系统要求。研究适用于WDM-PON系统的40Gb/s光传输技术是促进40Gb/s/λ WDM-PON发展与应用的关键，具有重要的研究价值。本项目主要针对40Gb/s/λ WDM-PON系统中上下行高频谱效率调制码型及产生方案、接收机均衡算法及WDM-PON环回系统搭建等展开了研究，主要研究内容及获得的成果如下..1. 通过仿真研究改进型双二进制、Nyquist-16QAM、Nyquist-4PAM、PM-DQPSK等高阶调制码型的频谱效率、色散容忍性、接收机灵敏度、系统复杂性与成本等关键指标并进行综合对比分析，提出了适用于40Gb/s/λ WDM-PON上行传输的EA 调制的改进型双二进制调制码型和基于IMDD Nyquist-16QAM、Nyquist-4PAM等简单、低成本、易集成的下行传输方案。.2. 提出时钟同步、自适应均衡/解复用、载波频偏估计和相位恢复算法的并行处理机制，降低DSP处理速率。时钟同步方面，提出一种适用于多种调制格式的反馈式并行全数字时钟算法。为有效补偿传输信道等对信号的损伤并降低DSP芯片速率，提出基于间隔样值并行滤波和利用累积误差并行更新抽头系数的自适应并行均衡解复用算法，并采用并行算法来补偿频偏和相偏。为解决时钟同步与自适应均衡相互的制约关系，基于并行处理的时钟同步与均衡联合处理方案，使两个模块相互配合。仿真结果表明，所提并行处理机制能有效的进行时钟同步和自适应均衡。 .3. 建立了上下行波长重用的单波长40Gbps PM-DQPSK WDM-PON实验系统和单波长40Gbps Nyquist-16QAM WDM-PON实验系统，实验结果显示该两种方案可分别实现100km和45km的有效传输。.4. 取得了一批原创性的研究成果，包括发表高水平论文30篇，其中SCI检索论文11篇，EI检索（含刊源）18篇，申请国家发明专利9项。.项目所取得的原创性的成果能够带动40Gb/s WDM-PON光发送及光接收机相关理论及应用技术的发展。