基于非本振相干检测的高速光纤通信系统

发布时间：2018-05-01 05:34

本文选题：相干光通信 + DSP算法　；参考：《华中科技大学》2014年硕士论文

【摘要】：数字相干光通信能够兼容数字均衡技术、高阶调制技术与先进复用方式，是实现高灵敏度、高频谱效率与超长距离传输的绝佳方案。考虑传统数字相干光纤通信系统存在问题，例如接收端昂贵的高质量本振光源，相干接收系统成本问题已成为数字相干光通信系统发展瓶颈。本论文在全面阐述数字相干光通信系统的理论基础上，进一步探究了基于模式复用的非本振零差相干检测系统方案，以及基于副载波复用的非本振外差相干检测系统方案。这两种技术都考虑了光纤通信系统的成本与系能的平衡，因而具有实用价值与研究意义。文章主要研究内容包括：在阐述数字相干光通信系统的基本结构与工作原理的基础上，分析了高阶调制格式的产生与相应的数字信号处理（DSP）算法。接着，本论文探究了基于模分复用的非本振零差相干通信系统的解析模型。通过112Gbps偏振复用-正交相移键控（PM-QPSK）传输系统的仿真结果验证该解析模型的精确性。通过仿真可以证实，DC偏置消除算法是减轻QPSK星座图畸变的必要手段，BER公式的理论值与仿真值的差异小于0.2dB@BER=1e-3，，预测的最佳信号与导频功率比与数值结果吻合的很好，使用改进的恒模算法（MCMA）的自适应均衡是提高系统系能的有效方案。最后，本论文探究了基于副载波复用的非本振外差相干检测系统的解析模型。通过112Gbps偏振复用-16正交幅度调制（PM-16QAM）传输系统的仿真验证该解析模型的精确性。本方案使用副载波复用技术产生三个密集分布的子载波，包含一个导频与两个16QAM信号。一个新型的DSP方案被提出来抑制外差检测带来的镜频干扰（IFI）。通过仿真， BER公式的理论值与仿真值的差异小于0.3dB@BER=1e-3。在验证解析模型的基础上，对关键系统参数的探究，包括滤波器参数，子载波频率间隔，以及信号与导频的调制指数比，可以进一步优化系统系能。
[Abstract]:Digital coherent optical communication can be compatible with digital equalization, high-order modulation and advanced multiplexing. It is an excellent scheme to achieve high sensitivity, high spectral efficiency and ultra-long distance transmission. Considering the problems of traditional digital coherent optical communication systems such as high quality local oscillator light source with expensive receiver the cost of coherent reception system has become the bottleneck of the development of digital coherent optical communication system. Based on the theory of digital coherent optical communication system, this paper further explores the scheme of non-local oscillator homodyne coherent detection system based on mode multiplexing and the scheme of non-local oscillator heterodyne coherent detection system based on subcarrier multiplexing. These two technologies take into account the balance between the cost and the energy of the optical fiber communication system, so they have practical value and research significance. The main contents of this paper are as follows: on the basis of explaining the basic structure and working principle of digital coherent optical communication system, the generation of high-order modulation format and the corresponding digital signal processing (DSP) algorithm are analyzed. Then, the analytical model of non-local oscillator homodyne coherent communication system based on module division multiplexing is explored. The accuracy of the analytical model is verified by the simulation results of 112Gbps polarization multiplexing and orthogonal phase shift keying (PM-QPSK) transmission system. The simulation results show that the bias cancellation algorithm is a necessary means to reduce the distortion of QPSK constellation. The difference between the theoretical value of the BER formula and the simulation value is less than 0.2 dB @ BER-1e-3, and the predicted optimal signal to pilot power ratio is in good agreement with the numerical results. Adaptive equalization using an improved constant modulus algorithm (MCMA) is an effective scheme to improve system performance. Finally, the analytical model of non-local oscillator heterodyne detection system based on sub-carrier multiplexing is explored. The accuracy of the analytical model is verified by the simulation of 112Gbps polarization multiplexing -16 orthogonal amplitude modulation (PM-16QAM) transmission system. The scheme uses subcarrier multiplexing to generate three dense distributed subcarriers, including one pilot and two 16QAM signals. A new DSP scheme has been proposed to suppress the mirror frequency interference caused by heterodyne detection. Through simulation, the difference between the theoretical value of BER formula and the simulation value is less than 0.3dBB @ Bert 1e-3. On the basis of verifying the analytical model, the key system parameters, including filter parameters, subcarrier frequency spacing, and modulation index ratio of signal to pilot, can be further optimized.
【学位授予单位】：华中科技大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：TN929.11

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