【作者】 陈宏伟；

【导师】 周炳琨；

【作者基本信息】 清华大学 ， 电子科学与技术， 2006， 博士

【摘要】 光标签交换(OLS)网络秉承了分组交换的思想,使用低速标签信号进行路由和交换选择,同时又保留了高速全光交换的特性,是实现未来光分组交换的一种很有前途的系统方案。光标签处理技术和光标签调制格式是实现光标签交换网络的关键技术,成为目前的研究热点问题。论文针对10Gb/s的副载波调制(SCM)标签方案提出了一种新型的Lyot-Sagnac全保偏光纤环镜滤波器,用于擦除副载波标签。这种标签擦除滤波器具有双端口输出、通带平坦、消光比高、多信道同时工作等特性。论文理论分析了这种滤波器的构成原理,并通过系统实验进行了验证。论文提出了两种可以用于40Gb/s甚至更高速率光网络中的光标签调制格式。一种是利用残留边带载荷及单边带副载波标签或波长标签的方案。理论提出了这种方案的可行性,并分析了残留边带载荷与标签的相互串扰特性。实验验证了两种波长标签的添加和删除方案,并进行了160km的长距离传输,实现了谱效率高达0.8bit/s/Hz的光信号格式。论文还对残留边带信号的质量进行了分析,研究了不同滤波器对NRZ、RZ、CSRZ、MDRZ等四种调制格式的影响,及不同伪随机码序列长度对滤波作用的反应。实验验证了两种滤波器对载波抑制归零码(CSRZ)系统表现的影响,得到了有益的结论。另一种是基于偏振调制的正交光标签方案。利用高速光载荷信号偏振态的变化来承载标签信息,有效避免了普通正交调制的消光比限制。论文提出的偏振调制是使用单一LiNbO3晶体相位调制器来实现的,在对40Gb/s高速脉冲序列调制时,LiNbO3晶体的双折射效应使得偏振信号调制不完全。论文提出了使用光学滤波的方法来消除这种双折射效应造成的影响,通过理论分析和实验验证取得了明显的效果。论文对偏振调制的正交标签方案进行了分析,实验搭建了标签添加、擦除的系统,并进行了偏振模弥散(PMD)和长距离传输实验,结果表明这种方案可以应用于高速光标签交换网络中。论文还提出了一种新型的光标签改写方案,省略了传统的光标签擦除操作,简化了标签处理过程和网络节点结构。更多还原

【Abstract】 Optical label switching (OLS) network inherits the soul of packet switching. The routing and switching information is embedded in the low speed label signal and it keeps the high speed all optical switching capacity, which is a promising solution for the future optical packet switching networks. Optical label processing methods and novel modulation formats are the key technologies in OLS network, which have attracted much attention.A novel Lyot-Sagnac polarization maintenance fiber loop filter is developed for erasing optical label in 10Gb/s subcarrier modulation (SCM) label format. This optical label eraser has the characters of double output ports, flatten transmission band, high extinction ratio and multi-channel operation. In this dissertation, the principle of the Lyot-Sagnac filter is analyzed theoretically and demonstrated experimentally.Two kinds of new modulation formats used in beyond 40Gb/s optical networks are proposed. One format combines the vestigial sideband payload and wavelength label. The feasibility and crosstalk between the payload and label are theoretically analyzed. Not only optical label adding and erasing methods of two wavelength labeling schemes are tested, but also 160km long distance transmission experiment is carried out. The results show that this format has the frequency efficiency up to 0.8bit/s/Hz. In this dissertation, the analytical results for vestigial filtering signals in conjunction with various modulation formats, e.g. NRZ, RZ, CSRZ, MDRZ, are derived, which also considering different pseudo-random bit sequences length. The performance of vestigial sideband CSRZ format employing two kinds of filters is experimentally demonstrated with meaningful results.The other high spectral efficiency modulation format is the orthogonal labeling scheme based on polarization modulation. This scheme utilizes the polarization states changes of payload to carry the label signal which avoidsthe extinction ratio limitation in the traditional orthogonal modulation. The polarization modulation is realized by only one LiNbO3 crystal phase modulator. The birefringence in the crystal causes imperfection polarization modulation with the input 40Gb/s pulses which can be eliminated by optical filtering method in this paper. Good performance is achieved through theoretical analysis as well as experiment verification. The novel orthogonal modulation format is analyzed and experimentally demonstrated by adding and erasing labels. At the same time, the polarization mode dispersion (PMD) and long distance transmission test are carried out. The results show that this format can be used in high speed optical label switching networks. A novel optical label re-writing scheme for this orthogonal format is given out. This scheme can omit the optical label erasing operation, simplify label processing and network node structure simultaneity.更多还原