【作者】 王亚平；

【导师】 吴重庆；

【作者基本信息】 北京交通大学 ， 光学工程， 2010， 博士

【摘要】 全光分组交换(OPS)作为下一代光网络的关键技术,使传输与交换完全在光域中完成,彻底克服光—电—光转换的瓶颈。其中,全光路由控制是全光分组交换的关键技术之一。全光路由控制是在光域中实现对光数据包的路由进行控制,包括帧头同步信息提取、帧头与净荷的分离、帧头识别、帧头周期性复制,以及控制光脉冲信号的同步展宽、光数据包的缓存等技术。本文针对全光路由控制的帧头复制、识别,以及光缓存技术进行了深入研究和探讨,取得的成果对于全光路由控制的实现和全光分组交换的发展有重要的参考价值。本文的创新主要包括：1、首次分析了输入数据包消光比(ER)对复制结果的影响,推导出输入消光比(RE)不高导致环形腔内光场产生的谐振项和输出复制数据包消光比恶化的公式。建立简化的有源环形腔复制器模型,分析了半导体光放大器(SOA)的自发辐射(ASE)噪声在环内累积导致输出信噪比(SNR)的下降问题,通过注入非循环直流(DC)辅助光抑制信噪比下降。实现了复制次数可控的光复制器,并利用SOA的增益饱和特性实现复制数据包功率均衡,获得数据包信噪比下降小于3dB且光功率几乎一致的20次以上复制结果。2、提出了一种基于有源环形腔的两级级联结构光复制器,复制次数成倍增长,而ASE噪声却以算术级数增长。成功实现了速率为2.5Gb／s光数据包100次复制,且复制光包的功率几乎一致、光包间隔严格相等,有效地减小了相位抖动。3、实现了两种适用于NRZ码的、基于太赫兹光学非对称解复用器(TOAD)的全光异或逻辑结构,大大降低了同步要求。方案一采用双向注入异或逻辑信号作为控制信号,利用该方案实现了2.5Gb/s NRZ码数据包的加密与解密。方案二采用同一端口注入异或逻辑信号,通过注入适当的直流辅助光避免了两路同步控制信号在SOA中竞争,利用调节直流辅助光光功率到最佳值减小相位差波动的方法,扩大了输入控制信号功率的容差。4、提出了光比较器功能模型以及应该具有的技术指标,利用异或逻辑实现了用于帧头识别的光比较器。利用同一端口注入控制信号的异或逻辑方案,实现了2.5Gb／s速率、8比特NRZ码帧头识别,输出多个判决脉冲。提出了基于平行排列3×3耦合器的、用于RZ码帧头识别的反馈式光比较器。5、针对立“8”型双环耦合干涉仪的相位及偏振不稳的问题,进行理论分析及实验验证,并利用偏振时变矢量定量描述偏振稳定性,结果表明：3×3耦合器的对称性、光纤环传输矩阵中的角θ(主轴与坐标轴的夹角)、光纤的双折射和两光纤环长度差是引起干涉信号偏振不稳的主要因素,光源波长漂移、双环环长差和光纤折射率随环境的变化是引起相位差变化的主要因素。采用短光纤固定连接方式和可重复性的偏振态调节方法；利用可调延迟线调节环长；设计了反馈电路实现光纤环路的相位补偿,可实现偏振态稳定、且输出光功率稳定在最大值的干涉,对实现立“8”型双环耦合光缓存器(DLOB)具有重要意义。更多还原

【Abstract】 In all-optical packet switching (OPS), transmission and switching are carried out entirely in the optical domain and the bottleneck caused by electrical-to-optical conversion can be broken. As a key technology of all-optical packet switching, all-optical routing control includes the header synchronization information extraction, header and payload separation, header recognition, header periodic replication, control pulse broadening, payload optical buffer and so on. This dissertation focuses on the header periodic replication, header recognition and payload optical buffer, and these conclusions achieved have important reference value for implementation of all-optical routing control and development of all-optical packet switching. What I have done during the PHD period are as follows:(1) The influence of the extinction ratio (ER) of the input packet on the replicator is analyzed for the first time. The resonant characteristics of fiber ring and ER deterioration due to low input ER are derived. Using the simplified mode of replicator, the analysis of signal-to-noise ratio (SNR) deterioration due to the accumulation of ASE noise is carried out and non-circulation assistant light is introduced to suppressing the ASE noise. Control of replication number is realized and 20 replications with identity amplitude, which SNR decline less than 3dB, are realized by the power equalization based on gain saturation characteristics of SOA.(2) The optical packet replicator using cascaded SOA-based active fiber ring is proposed. In this replicator, replication number can be expressed as the product of replication number of each stage, while the ASE noise accumulation can be expressed as the sum of replication number of each stage.100 replications with identity amplitude are realized and each interval of hundreds of replications is equal accurately which reduce the phase jitter effectively.(3) Two kinds of optical XOR logic gate based on terahertz optical asymmetric demultiplexer (TOAD), which is used for NRZ code and reduces the synchronization requirements greatly, is proposed. XOR logic gate, which the control signals are introduced into SOA from two directions, is used for all-optical NRZ encryption-decryption at 2.5Gbps. Another XOR logic gate, which control signals are introduced into SOA from the same port, is realized by avoiding the competetition of two synchronized signals in SOA with DC assistant light and improving the tolerance of the control signal power with the method of confining fluctuant rang of nonlinear phase difference at optimal value of assistant light.(4) The function model of optical correlator is proposed and its performance indicators are concluded.8 bit NRZ header recognition is realized at 2.5Gbps by the optical correlator based on XOR logic. Using planar 3×3 coupler, all-optical correlator with feedback for RZ header recognition is proposed.(5) For interferometer with vertical structure based on planar 3×3 coupler, the instability of phase and polarization will inevitably impact on the performance indicators. Theoretical analysis and experiments show that symmetry of 3x3 coupler, angles in the fiber ring transfer matrix, optical fiber birefringence and the length difference of two fiber rings are the main factors which influence the polarization, and wavelength shift of light sources, length difference of two fiber rings and the changes of optical fiber refractive are the main factors which influence the phase. These measures, such as adoping fixed detachment with short optical fiber and repeatable adjustment of the polarization state, making length difference of two fiber rings as small as possible by adjusting fiber delay line, and compensating phase of the fiber ring by designing feedback circuit, can make polarization state of interference signals stable and output optical power of interference at the maximum all the time, which is important to realize the DLOB with vertical structure。更多还原