Author Affiliations
Abstract
State Key Laboratory of Information Photonics and Optical Communications, Beijing University of Posts and Telecommunications, Beijing 100876, China
A complex-coefficient microwave photonic filter with continuous tunability is proposed and demonstrated, which has a compact structure and stable performance without splitting the optical path and tuning the polarization state. By only controlling the DC biases of the modulator, the amplitudes and the phases of the filter taps can both be tuned. The phase difference between the two filter taps covers a full 360° range from 10 GHz to 32 GHz. Frequency responses of the proposed filter are measured within 10–20 GHz with different center frequencies.
060.5625 Radio frequency photonics 070.2615 Frequency filtering 050.5080 Phase shift Chinese Optics Letters
2019, 17(10): 100601
Author Affiliations
Abstract
State Key Laboratory of Information Photonics and Optical Communications, Beijing University of Posts and Telecommunications, Beijing 100876, China
A stable and broadband microwave photonic phase shifter based on the combined use of a linear chirped fiber Bragg grating and optical single-sideband (OSSB) modulation is proposed and experimentally demonstrated. The quality of the radio frequency (RF) signal is improved by the spectral separation delay processing. The theoretical fundamentals of the scheme are explained and the phase shift can be controlled linearly by the wavelength of the light source. In the experiment, a full 360° phase shift with a 10 GHz bandwidth can be achieved and tuned dynamically, continuously, and stably.
060.3735 Fiber Bragg gratings 060.4510 Optical communications 060.5625 Radio frequency photonics Chinese Optics Letters
2016, 14(4): 040601
Author Affiliations
Abstract
State Key Laboratory of Information Photonics and Optical Communications, Beijing University of Posts and Telecommunications, Beijing 100876, China
We demonstrate the theory of chromatic dispersion (CD)-induced constellation rotation (CR) in a radio-over-fiber (ROF) link and a method for compensation. We also propose a 60 GHz full-duplex ROF system with vector signal transmission including no CD effect. The evaluation of 5 Gb/s 16 quadrature amplitude modulation signal transmission shows that the CD-induced CR can be entirely overcome due to the proposed method which is simply implemented through an optical phase shifter. The proposed ROF schedule is not only applicable for V-band (57–64 GHz) but also fits for W-band (75–110 GHz), or any other bandwidth.
060.4510 Optical communications 060.5625 Radio frequency photonics Chinese Optics Letters
2015, 13(1): 010604
Author Affiliations
Abstract
A two-dimensional (2D) optical true-time delay (TTD) beam-forming system using a compact fiber grating prism (FGP) for a planar phased array antenna (PAA) is proposed. The optical beam-forming system mainly consists of a TTD unit based on the same compact FGP, one tunable laser for elevation beam steering, and a controlled wavelength converter for azimuth beam steering. A planar PAA using such 2D optical TTD unit has advantages such as compactness, low bandwidth requirement for tunable laser sources, and potential for large-scale system implementations. The proof-of-concept experiment results demonstrate the feasibility of the proposed scheme.
060.3735 Fiber Bragg gratings 060.4510 Optical communications Chinese Optics Letters
2013, 11(10): 100606
1 华信邮电咨询设计研究院有限公司, 浙江 杭州 310014
2 浙江大学, 浙江 杭州 310014
3 北京邮电大学, 北京 100876
利用模糊数学理论对光网络中的多故障定位问题进行分析, 得到了光网络中多故障定位的模糊聚类模型。根据由模糊聚类算法得到的专家系统和由此确定的告警和故障之间的隶属函数公式进行故障定位。在格状光网络拓扑下进行多故障定位仿真实验, 得出故障定位成功率的对比图和时间性能的对比图。实验结果表明, 模糊聚类算法可以高效快速地定位故障。
模糊聚类 光网络 多故障 故障定位 fuzzy clustering optical network multi-faults fault location
北京邮电大学光通信与光波技术教育部重点实验室， 北京 100876
利用非共线相位匹配方法，研究了不同极化周期和不同非共线结构下周期极化铌酸锂晶体(PPLN)中的光参量放大(OPA)带宽与增益特性。光谱带宽和增益通过对相位失配进行泰勒级数展开并保留到二阶级数项得到，在计算过程中考虑到了晶体极化周期、非共线入射结构、PPLN晶体长度以及抽运光强度的影响。计算结果表明，参量带宽和增益带宽具有相似的特性，而且PPLN晶体的周期和非共线入射结构会对光参量放大的光谱带宽产生一定的影响，在同一波长处，通过调节晶体周期或非共线结构可以获得更大的带宽。在对增益的研究过程中发现，与增加抽运光强度相比，增加晶体的长度能更有效地增强参量增益，但是PPLN晶体的周期和非共线入射结构对增益几乎没有什么影响。
非线性光学 光参量放大 非共线相位匹配结构 周期极化铌酸锂 带宽 增益
1 北京邮电大学光通信与光波导技术教育部重点实验室, 北京 100876
2 中国移动通信集团公司, 北京 100032
在自动交换光网络(ASON)的控制平面内引入了通用多协议标签交换(GMPLS)协议, 使得光传送网络具备了更大的智能性。在控制平面拓扑和传送平面拓扑一致的情形下, 以GMPLS的“便道”技术为基础, 提出了一种改进型的基于标签交换路径(LSP )“双链路”恢复(DLR)的生存性机制。它对发生故障的节点两端链路同时实施迂回策略。通过对传统的链路恢复和“双链路”恢复进行细致地分析, 定量地给出了在这两种情形下, 信令恢复时间的比较方案。以美国AT&T实验室中研制的大型路由器上的数据为参数, 对上述两种不同恢复机制进行了对比分析, 进一步验证了该恢复策略提出的有效性。
光通信 自动交换光网络 双链路恢复 通用多协议标签交换 生存性 控制平面
北京邮电大学光通信与光波技术教育部重点实验室, 北京 100876
在大型骨干光网络中, 建立一条从源节点到宿节点的路由至关重要。在集中式网络管理系统体系下, 网络中动态路由信息以及故障状态信息, 通过路由的“泛洪”机制, 被传送到其他节点上实现资源信息共享,这对于连接的迅速建立, 恢复路由的快速启动将是不利的。尝试采用一种启发式算法-蚁群策略, 快速提高光网络中故障恢复的速度。该路由算法平台采用了分布式蚁群算法自动修复故障点, 解决了重路由的快速收敛问题; 依靠分布式代理机制构建管理平面和数据平面相互通信的机制, 完成诸如链路信息素的更新等功能。设计了一个网络故障的场景, 通过实验数据表明, 采用蚁群的分布式路由策略, 可以更快地实现路由信息的汇聚, 找到最佳的恢复路由。
光网络 蚁群算法 分布式移动代理 连接管理 故障管理
北京邮电大学 光通信与光波技术教育部重点实验室，北京100876
光网络中引入了共享风险链路组(SRLG)的概念，要求工作通道与保护通道不能处于同一个SRLG之中。文章提出了一种基于SRLG限制的动态共享通道保护算法——动态链路权重配置(Dynamic Link Weight Configuration, DLWC)算法，该算法的关键在于为链路定义了两个动态权重。在计算工作通道和保护通道时，它能综合解决SRLG限制、动态负载均衡和自陷等3个关键问题。
共享风险链路组 共享通道保护 负载均衡 自陷 WDM网状网 SRLG shared-path protection loading balance trap WDM mesh network
