| 题名 | 相位共轭光通信系统信号失真复原技术的研究 |
| 作者 | 步扬 |
| 学位类别 | 博士 |
| 答辩日期 | 2004 |
| 授予单位 | 中国科学院上海光学精密机械研究所 |
| 导师 | 王向朝 |
| 关键词 | 时域相位共扼 频域相位共扼 色散 自相位调制 自陡峭效应 自频移效应 交叉相位调制 |
| 其他题名 | Study on Compensation for Signal Distortion Due to Dispersion and Nonlinear Effects in Optical Fiber Communication System Using Optical Phase Conjugation |
| 中文摘要 | 网络数据业务的“爆炸式”增长使得构筑网络通信基础的光纤通信系统得到了飞速发展。随着光网络中单信道传输速率从40Gbit/s向160Gbit/s迈进；单光纤复用光波数向160个波长甚至更多发展，光纤色散和非线性效应已经成为影响光信号传输质量的主要限制因素。研发能够满足现代高速光通信系统要求的色散补偿和非线性失真复原技术成为下一代光通信网发展的前提和基础。相位共扼技术由于具有设计简单，补偿效率高，同比特率、信号调制方式无关，可同时补偿色散和非线性，可同时用于单波长系统和多波长系统等特点，使得其成为最有前景的色散补偿和非线性失真复原技术之一。本论文深入研究了基于相位共扼技术的色散补偿和非线性失真复原的理论基础，详细分析和讨论了基于该技术的各阶色散和各种非线性效应所致信号失真的补偿。论文的具体研究内容和所取得的创新性成果如下：（一）研究了单波长系统中基于时域相位共扼技术的色散和非线性效应所致失真的复原。（1）研究了二阶、三阶、高阶色散对系统的影响，发现时域相位共辆技术能够完全复原二阶色散、四阶色散等偶数阶色散所致的信号失真，但是不能单独复原三阶色散等奇数阶色散所致的信号失真。提出了将时域相位共扼技术与高阶色散管理相结合的方法，利用该方法能够复原奇数阶色散所致的信号失真。（2）研究了在群速度色散作用下啁啾对系统的影响，发现脉冲的初始啁啾不会影响中距相位共辆系统对信号失真的复原，它只影响脉冲在光纤中的传输演化。合适的初始啁啾会产生初期窄化和末期窄化。提出了利用凋啾脉冲的这种传输特性来优化相位共扼系统的总体结构设计，改善系统传输性能。（3）研究了自相位调制，自陡峭效应和自频移效应等非线性效应对系统的影响，发现时域相位共扼技术能够完全复原自相位调制和自频移效应所致的信号失真，但是不能单独复原自陡峭效应所致的信号失真。提出引入合适的小色散于系统中，该方法能够明显减小该系统中自陡峭效应导致的信号失真。（4）对于超高斯脉冲，研究发现时域相位共辘系统依然能够复原色散和非线性效应所致的信号失真。但是由于锐度的增加，脉冲的上升沿和下降沿的变陡，脉冲的展宽速度会迅速增大。（二）研究了单波长系统中基于频域相位共扼技术的色散和非线性效应所致失真的复原。（1）研究了全部色散和非线性效应对系统的影响，发现频域相位共扼技术能够复原包括偶数阶和奇数阶在内的全部色散、自相位调制和自陡峭效应所致的信号失真，不能单独补偿自频移效应所致的信号失真。（2）为了弥补时域相位共扼技术和频域相位共扼技术各自的不足，提出了将二者结合的混合补偿方法。研究发现它能够复原单波长系统中全部的色散和非线性效应所致的信号失真。（3）研究了在全部色散和非线性效应作用下，啁啾对时域和频域相位共扼光通信系统的影响，发现啁啾能够极大地影响系统脉冲信号的传输，导致信号的严重失真，因此，在高速通信系统中，应尽量避免啁啾的产生，或者应用混合补偿系统，以减小啁啾对高速信号传输的影响。（三）提出并研究了在多波长系统中基于频域相位共扼技术的交叉相位调制所致信号失真的复原。（l）研究了在中距频域相位共扼通信系统中交叉相位调制对信号传输的影响，发现频域相位共扼技术能够准确地复原交叉相位调制所导致的信号失真。并且群速度色散和自相位调制所导致的信号失真也同时得到准确的复原。（2）研究了初始啁啾和时延对系统的影响，发现初始啁啾和初始时延不会影响系统对交又相位调制所致信号失真的复原，它们只会影响信号的传输过程。合适的初始时延和脉冲啁啾有利于频域相位共扼技术对交叉相位调制所致信号失真的复原。 |
| 英文摘要 | Boosted by the explosion of internet network services, optical fiber communication systems are expanding quickly. Single-channel rate is increased from 40Gbps to 160Gbps, channel numbers of single fiber are increased to 160 and more. Dispersion and nonlinear effects become key limit factors degrading system transmission. Researches on compensation for distortion due to dispersion and nonlinear effects are the preconditions and foundations of next generation network. Optical phase conjugation (OPC) is a promising compensation technique because of its simple design, high efficiency, independence of rate and modulation format, simultaneous compensation for dispersion and nonlinear effects, widely application in single-wavelength system and WDM system. In this dissertation, theory of compensation for dispersion and nonlinear effects based on OPC is studied. Compensation for distortion due to dispersion and nonlinear effects in optical fiber communication system using OPC is analyzed and discussed. The research contents include: (I) Compensation for distortion due to dispersion and nonlinear effects in fiber communication system using time domain phase conjugation (TDPC) is studied. (1) The influences of dispersion including group velocity dispersion (GVD), third-order dispersion (TOD), fourth-order dispersion (FOD) and higher-order dispersion (HOD) on the TDPC system are analyzed and discussed. It is found that TDPC can compensate for distortion due to even-order dispersion (EOD), but not for distortion due to odd-order dispersion (OOD). The TDPC system with higher-order dispersion management is proposed to compensate for distortion due to OOD. (2) The influences of initial chirp on the system affected by GVD and SPM are considered. It is found that initial chirp does not affect the ompensation and only influences evolution of pulses. The right chirp leads to the initial and final narrowing stages of pulses. It is useful for optimizing the design of the system and improving compensation performance for distortion. (3) The influences of nonlinear effects including self-phase modulation (SPM), self-steepening (SS), self-frequency shift (SFS) on the system are studied. It is found that TDPC can compensate for distortion due to SPM and SFS, but not for distortion due to SS. The introduction of small dispersion is proposed to counteract the distortion due to SS. (4) When super-Gaussian pulses are considered, it is shown that TDPC system still can compensate for distortion due to dispersion and nonlinear effects. Because the degree of sharpness of the pulse edges is increased, pulse width is broadened rapidly. (II) Compensation for distortion due to dispersion and nonlinearity effects in fiber communication system using frequency domain phase conjugation (FDPC) is studied. (1)The influences of all wth-order dispersion and all nonlinear effects on the FDPC system are analyzed and discussed. It is found that FDPC can compensate for distortion due to all nth-order dispersion, SPM and SS, but not for distortion due to SFS. (2) The combination of TDPC and FDPC is proposed to compensate for the distortion due to all rcth-order dispersion and all nonlinearity effects. (3) The influences of chirp on the system affected by all dispersion and all nonlinearity effects are analyzed. It is found that in FDPC system or TDPC system, chirp can impair and degrade the system transmission severely. Chirp must be avoided in high-rate communication system, or hybrid compensation is used to suppress impairments due to chirp. (III) In a WDM system, a technique based on FDPC to suppress impairments due to cross-phase modulation (XPM) is proposed and studied. (1) The influence of XPM on WDM system using midway FDPC is analyzed. It is found that FDPC can compensate for distortion due to XPM. GVD and SPM can be compensated simultaneously. (2) The influences of initial chirp and time delay on the system are considered and analyzed. It is found that initial chirp and time delay don't affect the compensation. They influence evolution of pulses. The right initial chirp and time delay can improve compensation performance for pulse distortion. |
| 语种 | 中文 |
| 内容类型 | 学位论文 |
| 源URL | [http://ir.siom.ac.cn/handle/181231/15518]  |
| 专题 | 上海光学精密机械研究所_学位论文 |
| 推荐引用方式 GB/T 7714 | 步扬. 相位共轭光通信系统信号失真复原技术的研究[D]. 中国科学院上海光学精密机械研究所. 2004. |
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