双光纤波分复用网阻塞率研究

研究了双光纤波分复用互联网在不同网络容量使用率时的阻塞率,主要对单光纤网络使用波长变换器和双纤网络在波长数不同时对网络阻塞率的改善情况做了仿真比较,结果表明仅仅在低阻塞率时波长变换器给网络所带来的增益非常有限,双纤网络可以达到其效果。     

部分波长光网络中的动态波长分配算法

为适应网络中不同服务质量（QoS）的光路建立请求具有不同的优先级的情况,提出了一种用于部分波长可变网络中支持QoS的动态波长分配算法。该算法对网络中的业务请求分高、低两个优先级进行处理。对于高优先级的光路建立请求,通过充分利用网络中已配置的波长转换器实时改变可用波长集,以降低高优先级业务请求的阻塞率。对低优先级的光路建立请求,只考虑所选路径的当前位置是否有波长转换器来改变可用波长集,保证了低优先级的光路建立请求速度。仿真结果表明,该算法既能保证较高优先级的光路建立请求具有较低的阻塞率,又充分利用了有限的网络资源,实现了对波长转换器的最优利用。     

多波长光网络的动态路由等效算法

针对多波长光网络的特点，提出了一种动态路由和波长分配的等效算法。采用波长图、增加虚拟源节点和目的节点等技术，把多波长网络转化为等效的单波长网络，避免了求解路由和波长分配两个复杂子问题，简化了算法的程序设计。利用最短径算法进行路由和波长分配可以求得问题的最优解，从而有效地降低了网络阻塞率。仿真结果表明：与FAR-2D算法相比，在4和8波长的全波长转换网络中，采用等效算法阻塞率最大降幅分别达到0．02、0．025。     

一种新型的动态路由和波长分配综合算法

讨论了WDM光网中，在动态业务流量和有限范围波长变换情况下的动态路由和波长分配问题。基于Moone-Dijkstra算法，考虑到动态波长变换的可能和限制，提出了一种新型的、可实现动态最小代价路由和最佳虚波长通道的综合启发式算法(DMC-OVWP)。该算法对路由子问题和波长分配子问题既相互独立，又相互结合，优化了RWA。以中国教育和科研计算机网(CERNET)为拓扑背景，基于本算法进行了计算机仿真，并对实验结果进行了比较分析，证明本算法可充分利用网络信息获取较低的阻塞率。     

超材料电磁隐身波长变换器的设计与仿真

通过坐标变换理论设计出一种新型功能性超材料电磁隐身装置——波长变换器。该装置一方面能够导引入射波在装置的内部传播,并使得波在装置的外部恢复原始的传播特性而不引起波形的变化;另一方面能够在装置内部改变电磁波波长而不产生波的散射现象。在理论推导出波长变换器的电磁参数张量后,采用有限元仿真软件对该装置进行数值分析,仿真的结果验证了该装置设计的正确性。     

波长路由在并行计算机光互连中的应用

提出了一种波长路由并行光互连技术，其路由直接在源端用目标地址选择波长来建立，各波长有独立传输路径并采用光通道复用，路由变换节点为全光结构，光信号在变换节点处无转发延迟。此技术可应用于并行计算机互连网络和分布式高性能计算机群的互连网络。     

分光光度计波长误差的产生和控制方法

通过对影响分光光度计测量准确性的因素进行分析，认为波长准确度是其中的主要因素。对检定用波长标准进行特性研究，确定各种标准器的用途；对波长误差的构成原理进行分析，确定波长误差的调整方法；综合对检定波长产生误差的相关方面进行论述，全面提出了控制波长误差的具体方法，为控制影响分光光度计测量准确度的波长误差提出了一套解决方案。     

多纤多波长光网络的动态路由等效算法

针对多光纤多波长光网络的特点,提出了一种动态路由和波长分配的等效算法。采用波长图、增加虚拟源节点和目的节点、引入光纤数量矩阵等技术,把多纤多波长网络转化为等效的单波长网络,大大简化了算法程序的复杂度。采用最短径算法作为算法的基础,可求得每次业务在全网范围内的路由和波长分配的最优解。仿真结果表明,当网络呼叫量为60时,全波长转换情况下,2纤、4纤网络的阻塞率分别为0.1116、4.3×10-5。     

基于准Z源的本质安全开关变换器的设计

针对一种输出本质安全型准z源Buck变换器拓扑结构进行了分析,准Z源Buck变换器可以有效地延缓输出端短路或开路时变换器向短路／开路故障点的释能速度,与截止型输出保护电路相配合,可以有效地减小火花放电能量,提高电源的本安特性。由于当准zNN络参数L1、C1远小于常规变换器滤波网络参数LC,因此本文按常规Buck变换器完成了准Z源Buck变换器的设计,利用LM2576-ADJ芯片对BUCK变换器进行了设计,论文最后采用常用的截止型输出保护电路验证了理论分析的正确性。     

分光光度计波长误差分析及波长的调整

文章通过对分光光度计波长误差来源的分析，阐明了对分光光度计进行检定的意义及波长调整的方法。     

Analytical models of blocking probability for multi-granularity cross-connect-based optical networks

Multi-granularity optical cross-connect (MG-OXC)-based optical network is a promising optical network architecture as it is capable of flexible switching at different granularity levels. In MG-OXC-based optical networks, wavelength conversion (WC) capability and the number of usable add/drop ports of the nodes are two key factors affecting its performance. Two analytical models of blocking probability for MG-OXC-based optical networks both without WC capability and with sparse WC capability are proposed, exploiting Erlang?s loss formula and birth?death process. Based on the models and simulation, the impact of WC capability and the number of add/drop ports on the blocking probability are investigated. Three kinds of granularities (i.e. fibre, waveband and wavelength) are considered in MG-OXC nodes to reduce the complexity and size of switch fabric. Both the analytical and simulation results are given on two network topologies under dynamic traffic patterns. Simulation results show that the proposed models are accurate and effective for the analysis of blocking probability in MG-OXC-based optical networks.     

Reservation signalling mechanism for reducing blocking probability in optical burst switching networks with limited wavelength conversion capabilities

First, the optical burst switching (OBS) network with limited wavelength conversion capability (LWCC) is decomposed into multiple wavelength continuous segments according to the position of wavelength converters. Based on the decomposed network model, two reservation signalling mechanisms for OBS-LWCC networks, namely wavelength-amend-on-demand (WAoD) and contention-based limited signalling protocol (CLSP), are proposed to reduce the blocking probability in the OBS-LWCC networks. In WAoD, the congested node sends a feedback message to the closest upstream switch with wavelength conversion capability. The notified switch will change the burst wavelength to the one assigned by the congested node to avoid collision in advance. Extensive simulation results indicate that by applying the wavelength reconfiguration method to the core nodes without wavelength conversion capability, the proposed WAoD scheme can improve the blocking performance in the OBS-LWCC networks significantly. Furthermore, CLSP, which combines the burst time-slot reconfiguration with the wavelength reconfiguration of WAoD, always has the lowest burst loss probability when compared with both the conventional and the proposed reservation mechanisms.     

Dynamic O-band to C-band wideband wavelength converter for integrated VCSEL-based optical interconnects

ABSTRACT

Real-time wavelength conversion and traffic routing at key network nodes is a fundamental requirement for current optical interconnects. This work experimentally demonstrates a broadband wavelength conversion from O-band to C-band employing commercially available, power efficient VCSELs. A 1310?nm VCSEL is directly modulated with 8.5 Gbps data and transmitted over 22?km G. 652 fibre with a 0.53 dB penalty. The received data is used to run a 1550?nm VCSEL located at the network integration node, achieving the first reported wavelength conversion from O-to-C-band. VCSEL wavelength tuneability with changing bias current functionality is further exploited to route the converted wavelength over 400?GHz spectra range for integration into wavelength flexible networks. The newly converted wavelength is transmitted over 24.7?km of G. 655 fibre, incurring a maximum penalty of 1.86?dB. Results from this work proves an enabling development technology for wavelength converters for transparent contention resolution in current and future optical Interconnects.     

太阳光下可调谐激光脉冲的波长和入射方向的实时测试和系统研究

提出了在恶劣环境条件下,应用衍射光栅测量宽波长范围可调谐脉冲激光波长和入射方向的实时测试方法,并设计了实验系统,在该实验系统中,光电传感器采用了ATMEL公司的50 MHz线阵探测器,由高速度数字信号处理器TMS320VC5509处理该传感器获得的信号,获得入射激光的波长和入射方向,实验结果表明,该系统能达到10ns的波长分辩率和1(°)的角度分辩率;该测试方法可用在相干探测激光告警接收机中.     

Investigation of optimum wavelength converter based on nonlinear polarisation rotation in a bulk SOA

This work is focused on understanding and optimising the physical mechanisms responsible for wavelength conversion based on cross-polarisation modulation (XPolM) in a bulk semiconductor optical amplifier. A comparison is made between the conversion performance that can be achieved with cross-gain modulation (XGM) and XPolM in co- and counter-propagation configurations. Wavelength independent conversion can be achieved when nonlinear polarisation rotation and XGM effects are balanced in the case of non-inverted wavelength conversion     

利用SOA中的四波混频实现2.5Gb/s信号的波长变换实验

基于SOA中四波混频效应,对中心波长为15474nm,调制速度为25Gb/s的光信号进行波长变换实验,最大波长变换距离达98nm。