Investigation of wavelength division multiplexing ring network topology to enhance the system capacity

In this paper, we have investigated the wavelength division multiplexed (WDM) system using ring network topology. This network is used to increase the capacity with eight optical add/drop multiplexers (OADMs) by using dispersion compensating fiber and semiconductor optical amplifier (SOA) to achieve a distance up to 1600 km. It is observed that network shows the acceptable results at 15 Gbps data rate with 100 GHz channel spacing. The OADM nodes are also varied to investigate the network performance in the term of BER and Q-factor.     

Performance investigation on DWDM optical ring network to increase the capacity with acceptable performance

The performance of DWDM ring network topology is investigated with 13 × 15 Gbps channels without using dispersion compensating fiber among the 3 channels are added and droped using OADM, respectively. Each OADM node having 70 km distance between each other. This ring network topology is evaluated by considering the signal quality factor and BER for different input power at all nodes. Further, this ring network topology is also investigated for different data rate at all nodes.     

全光地址识别机理的研究

在面向分组业务的全光交换系统中,采用全光地址处理技术可以减少处理时延,大大提高信息处理速度和网络吞吐量,对全光网络的研究具有重要意义。分析了光正交码的自相关性与互相关性,并将其特性应用于全光传送网中,以针对未来基于光分组业务的全光环网为例,提出了一种光分插复用器的新型结构,给出了总体应用设计规则,重点研究和分析了全光地址识别机理和相关的应用设计方法,给出了针对全光环网组网规模的仿真分析结构和基本实验结果。结果表明采用所提出的设计原则和设计方法来实现全光地址识别是可行的。     

基于光纤光栅波长路由的光纤自愈网

介绍了一种基于光纤光栅波长路由的全光双纤单向自愈环网,环内四节点具有16×10Gbit/s的传输能力。利用啁啾光纤光栅(CFBG)的波长可选择特性,实现了分布式的上下话路和波长选择功能,同时有效地补偿了传输色散。网络管理参照了网络管理协议(SNMP)的网络管理模型,通过对网络的重要参数进行实时监测来控制网络运行。实验结果表明,当环上任一处光缆发生故障时,通信业务能够自动恢复,恢复时间小于50ms,可实现网络的快速自愈,符合ITU-T G.841的建议规定。     

三种结构的光分插复用器特性比对研究

 针对电交换路由成为全光网通信和密集波分复用等高速信息传递网的电子瓶颈的现状,开展对全光光分插复用器的理论和实验研究。介绍了基于Mach-Zehnder干涉仪和FBG结构、基于FBG和光环行器结构以及一体化光纤光栅耦合器结构的光分插复用器的工作原理,实际构建了3种结构的光分插复用器,并分别搭建测试系统进行了单波长光信号上/下行实验研究,对比了这3种光分插复用器结构的性能和优缺点,为全光光分插复用器的设计制作提供了参考。     

A Novel OADM Based on Fiber Gratings

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OADM环网的实验研究

研究了光分插复用器(OADM)的关键技术,重点分析了相关的实现技术,完成了利用OADM构建全光环网的实验研究,给出了重要的实验数据,包括眼图、光谱图、光信噪比、保护与恢复等,并对这些实验数据进行了分析,为光传送网的设计与构建提供了重要的参考依据.     

基于实验物理与工业控制系统的EAST真空抽气及加料控制系统设计

介绍EAST 真空及加料监控系统底层和顶层的架构设计、连锁保护设计、运行模式设计以及系统部署。在底层架构中,真空抽气和加料监控系统分别采用两套相互独立的光纤环网拓扑,构成双光纤环网结构。顶层设计主要采用符合大科学装置规范的实验物理与工业控制系统(EPICS)架构。系统设计主要特点是将底层双光纤环网结构拓扑和顶层EPICS 架构相结合,构建了大型分布式真空抽气和加料数据采集与监视控制系统。测试结果表明整套监控系统运行稳定可靠,该监控系统不仅为EAST 装置实验提供了可靠支撑,同时也为未来其它大科学装置的监控系统构建提供参考和借鉴。     

莫阿光纤光栅的光谱特性及其在光分插复用器中的应用

从耦合模理论出发，结合莫阿光纤光栅的结构特性，运用分段均匀和传输矩阵法对幕阿光纤光栅的光谱特性进行了理论分析和数值计算；详细研究了线性啁啾莫阿光纤光栅的滤波特性，在此基础上，提出了一种新型的基于线性啁啾莫阿光纤光栅的光分插复用器的结构设计方案。     

Performance investigation of ring network topology in the presence of semiconductor optical amplifiers

The performance of 60 user ring network topology is investigated in the presence of semiconductor optical amplifiers. This ring network topology is evaluated by considering the signal quality factor, eye closure and received power for different signal input power. Further, this ring network topology is investigated with multiple numbers of spans. It is reported that, the maximum number of nodes supported by this ring network is >300 with acceptable quality and received power.     

波分复用全光通信网中的放大自发辐射噪声积累效应研究

给出了一种全光通信网波长域计算机模拟方法，模拟了波分复用信号经过３个光分插复用节点后的信号及放大自发辐射积累的光谱图，并与实验结果进行了对比。计算了波分复用信号经过５０个光分插复用节点极限情况下的信噪比，结果表明放大自发辐射噪声积累造成的信噪比下降仍然可以保证接收机在１０Ｇｂ／ｓ时的误码率小于１０＾－９。这些结果可以被应用到未来国家或地区级全光通信网中。     

基于网状光网络的智能实时监测保护系统的研究

目前光网络的拓扑结构越来越复杂,逐渐向网状结构光网络发展。提出了一种新的网状光网络智能实时在线监测保护方案,该方案采用下层嵌入式监测设备＋上层网管中心的模式。在嵌入式监测保护设备上加入保护光纤路由计算的功能,由嵌入式监测保护设备事先用路由算法计算出每条工作光纤的备用光纤路由,在工作光纤发生故障时及时进行切换。该方案实现了真正无人值守的光网络智能实时在线监测保护设备,适应网状光网络的发展要求,实现网状光网络的透明无阻断通信。     

一种新型光分插复用器及其在WDM自愈环网中的应用

提出了一种新型的基于FBG和光环形器的双向光分插/复用器结构.它的结构简单,网络配置灵活,而且可实现单纤双向环网中功率放大.结合该OADM,首次给出了在单纤双向DNI环网实现保护的策略,指出此结构在各种WDM网络中实现单纤环网保护的可行性.     

Design and performance analysis in multiuser optical CDMA systems

The article presents comparative performance analysis of the proposed Optical CDMA system for 32 and 16 users with two dimensional codes. Numerical simulations have been done under interference significant environment, considering noise and dark current at data rates 2.5, 5, 7.5 and 10 Gbps over single mode fiber for transmission distance of more than 270 km. Results illustrate overall good performance, degraded with augment in bit rate and transmission distance, impervious with raise in number of simultaneous active users. Depicts significant performance improvement with inclusion of forward error correction RS (255,239), for low attenuation and chirp factor. It perceived, this is one of the efficient functional techniques for next generation broadband optical networks together with higher security owing to encoding and decoding, as it allow multiple users in the network to access the same fiber channel asynchronously.     

DWDM self-healing access ring network with cost-saving, crosstalk-free and bidirectional OADM in single fiber

A cost-saving, crosstalk-free and bidirectional optical add-drop multiplexer (B-OADM) based on cascaded thin-film optical add-drop filters (TFOADFs) with optical circulators as well as the optical protection function promptly restored at the access node for a single-fiber self-healing access ring network are proposed and demonstrated. Using this B-TFOADM configuration, no crosstalk appears on the dropped and added channels, respectively. The bit-error rate performances in this B-OADM are investigated in a 2.5-Gb/s DWDM system, showing no intraband and interband crosstalk-induced power penalties. Such crosstalk-free and bidirectional architecture greatly simplifies the hub complexity as well as the low-cost components at each node are employed.     

可重构的多波长光分插复用节点研究

设计并研制出了一种可灵活重构的多波长OADM,建立了OADM级联光信噪比的理论计算模型并进行了分析计算,给出了OADM的内部功率预算.最后对OADM设备进行了测试,所有性能指标都达到设计要求,目前已经通过工程验收,并正式在“中国高速信息示范网(CAINOnet)”中运行.     

军用车载光纤数据总线的拓扑研究

研究和量化了拓扑和访问耦合器对光纤网络物理性能的影响。针对双总线形、星形、环形和双环形四种光纤网络拓扑,比较它们的光纤需求长度、平均传播延迟、传输衰减、最大比特率及容错。结果表明:在100个节点情况下,星形拓扑需要的光纤长度是双环形的3.8倍,而双环形的平均传播延迟是星形的3.3倍;双总线形的传输衰减最大,在10个节点情况下,要求接收器的动态灵敏度达24dB;假设使用垂直腔面激光器和渐变折射率多模光纤,使用容错耦合器导致最大比特率性能降低,双总线形和星形的最大比特率与节点数相关。这些结果可为选择光纤数据总线拓扑和访问耦合器提供参考。     

Multiple-Output Fiber-Ring Lasers and Amplifiers in a Hybrid CATV and ADSL Broadcasting Optical Fiber Communication System

In this article we propose two kinds of new fiber ring structure with a semiconductor optical amplifier. The first structure is a one-fiber-ring amplifier with an 8 × 8 fiber coupler and a semiconductor optical amplifier (SOA). The second fiber ring structure is a two-fiber-ring laser including an 8 × 8 fiber coupler, a 2 × 2 E/O modulator, and an SOA. The 14-output spectra of the fiber laser are measured. The gain coefficients of each port of the multiple-output-fiber-ring amplifiers are also measured. We apply these two kinds of fiber ring structures in a hybrid CATV and ADSL broadcasting optical fiber communication system. This application can develop a broadcasting system with large coverage area without using many laser diodes and optical amplifiers. The performance of such a system is also analyzed in this article.     

Multiple-Output Fiber-Ring Lasers and Amplifiers in a Hybrid CATV and ADSL Broadcasting Optical Fiber Communication System

In this article we propose two kinds of new fiber ring structure with a semiconductor optical amplifier. The first structure is a one-fiber-ring amplifier with an 8 × 8 fiber coupler and a semiconductor optical amplifier (SOA). The second fiber ring structure is a two-fiber-ring laser including an 8 × 8 fiber coupler, a 2 × 2 E/O modulator, and an SOA. The 14-output spectra of the fiber laser are measured. The gain coefficients of each port of the multiple-output-fiber-ring amplifiers are also measured. We apply these two kinds of fiber ring structures in a hybrid CATV and ADSL broadcasting optical fiber communication system. This application can develop a broadcasting system with large coverage area without using many laser diodes and optical amplifiers. The performance of such a system is also analyzed in this article.     

Tunable 19 × 10 GHz L-band FP-SOA based multi-wavelength mode-locked fiber laser

We present a multi-wavelength mode-locked fiber ring laser incorporating a semiconductor optical amplifier (SOA) and a Fabry-Perot semiconductor optical amplifier (FP-SOA). Because the gain of the SOA is depleted by an external injection optical signal, the SOA acts as a loss modulator. The FP-SOA serves as a tunable comb filter. The presented laser source can generate 19 synchronized wavelength channels with the extinction ratio of about 21 dB, each mode-locked at 10 GHz, and mode-locked pulse width is about 40 ps. Oscillation wavelengths band can be tuned by adjusting the bias current of the SOA, and wavelength spacing also can be changed by using a tunable optical delay line (ODL) or a temperature controller. The polarization-insensitive devices ensure that the output power is rather stable. This fiber laser has potential applications in longer waveband (L-band) within the low-attenuation window.