最新刊期
      卷 ， 期 2 ， 2009
      • Zhang Xia1,Wang Fang1,Niu Huijuan1,Xu Hengying1,Bai Chenglin1,Zhang Xiaoguang1
        Issue 2, Pages: 1-2(2009) DOI: 10.13756/j.gtxyj.2009.02.015
        摘要：By simulation,we obtain the Degree Of Polarization（DOP） value and the residual Differential Group Delay（DGD） value before and after ther Polarization Mode Dispersion（PMD） compensation of Non-Return-to-Zero（NRZ） code,Carrier-Suppressed Return-to-Zero（CSRZ） code,NRZ-DPSK and CSRZ-DPSK signals.The results show that compared with the binary On-Off-Key（OOK） format,more DOP values after the DPSK compensation are distributed close to 1 and the residual DGD values are smaller.In addition,CSRZ-DPSK has the best effect of PMD compensation and is the preferred modulation format for the dynamic integration of PMD mitigation and compensation.  
        关键词：modulation format;PMD;compensation;DPSK   
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      • Huang Lili,Li Xiaodong,Ye Yunfeng,Zhao Jijun
        Issue 2, Pages: 10-13(2009) DOI: 10.13756/j.gtxyj.2009.02.017
        摘要：Defined by the Internet Engineering Task Force（IETF） Path Computation Element（PCE） work group,the PCE-based MPLS/GMPLS network architecture can effectively contribute to the end-end path computations in multi-layer networks.In view of the development trend of ASON routing technology,this paper gives,on the basis of the Request For Comments（RFC） of the relevant PCE,a fairly systematic description of its system architecture,discovery mechanism and strategy and focusing on elaborating its applications in ASON routing,its path protection and recovery mechanism,indicating that the PCE technology will become the first choice of the ASON routing technology.  
        关键词：ASON;routing technology;PCE discovery;PCE communication protocol   
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      • Luo Jianhong1,Fan Zhiwen2,Wang Hongbin1,Nie Jiancheng1
        Issue 2, Pages: 16-18(2009) DOI: 10.13756/j.gtxyj.2009.02.019
        摘要：As a packetized network with transmission functions,Packet Transport Network（PTN） is mainly used for the IP service bearing of Radio Access Networks（RAN）.Hence,its time synchronization is of major significance.This paper introduces the PIN synchronization demands and the IEEE 1588 sync technologies,describes the requirements and methods of PTN transport time synchronization and discusses the synchronization solutions of PTN-based node B of TD-SCDMA.  
        关键词：PTN;TD-SCDMA node B;clock synchronization   
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      • Zheng Yuan1,Lu Siqing2,Dong Ximing1
        Issue 2, Pages: 19-21(2009) DOI: 10.13756/j.gtxyj.2009.02.020
        摘要：High reliability is the most important issue to be dealt with when the Ethernet technologies have reached to the carrier-level requirement.This paper enumerates the Ethernet technologies relevant to reliability,including Ethernet linear protection and Ethernet ring protection.In addition,it introduces the Bidirectional Forwarding Detection（BFD） protocol in the link protection and its application in the error detection in Ethernet linear and ring protections.  
        关键词：Ethernet protection;Ethernet ring protection;BFD;reliability   
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      • Wu Zhangbin,Chen Guang,Yang Bojun
        Issue 2, Pages: 22-24(2009) DOI: 10.13756/j.gtxyj.2009.02.021
        摘要：The Quantum Key Distribution（QKD）network consists of network nodes connected according to a certain topological structure.The existing QKD networks can be divided into three main categories of optical node,trusted relay node and quantum node QKD network in view of their node performances.This paper reviews the research progress of the QKD networks and makes an all-round comparisons and analysis of their structures and performances,on the basis of which a novel highly-efficient and practical QKD network scheme is presented.  
        关键词：quantum key distribution network;quantum repeater;quantum node   
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      • Shi Junliang1,Wang Liufang2
        Issue 2, Pages: 25-27(2009) DOI: 10.13756/j.gtxyj.2009.02.009
        摘要：This article introduces the basic principle of DiffServ and SNMP models.In the SNMP model,there a VOD Server for on-demand clients and a BCM server and an Agent software in the VOD Server mainly for bandwidth application and BCM used as the core of the system.The edge router in DiffServ model is equipped with a classifier and a regulator mainly for data flow classification,marking and shaping,while the internal router is only used for forwarding.This article describes a new mechanism for DiffServ and SNMP-based implementation of end-to-end IPv6 QoS.  
          
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      • Wu Jianxue
        Issue 2, Pages: 28-31(2009) DOI: 10.13756/j.gtxyj.2009.02.010
        摘要：As the penetration and extension of packet switch technologies into the optical layer,Optical Packet Switching（OPS） offers an ideal platform for multiple services including voice and data in the future optical networks and,driven by IP services and promoted by the continuously developing optical switch technologies,is sure to have a broad prospect of applications This article describes the layering structure and the network architecture of OPS-based transport networks,gives the layering reference model of the existing OPS transport networks in near,middle and distant future phases of development,on the basis of which it discusses the migration strategies for optical transport networks to OPS-based transport networks.  
        关键词：OPS;network architecture;migration strategies   
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      • Wang Tao,Huang Bing,Liang Xiaopeng,Li Pingan
        Issue 2, Pages: 32-34(2009) DOI: 10.13756/j.gtxyj.2009.02.011
        摘要：As the capacity of optical transport networks increases,rapid fault identification and location have become increasingly important.In this paper,the optimum allocation of the fault monitoring equipment in current optical networks is studied and the maximum fault coverage and the minimum number of the monitoring equipment are achieved by the algorithm optimization.On this basis,a simulation platform is constructed and the simulation results indicate that when the optimized algorithm is adopted the number of the equipment to be monitored is the minimum,while the redundant alarm amount is reduced to the maximum and the faults are located fast and efficiently.  
        关键词：optical network;fault;monitoring optimization   
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      • Lian Jian,Zhu Bo
        Issue 2, Pages: 35-37(2009) DOI: 10.13756/j.gtxyj.2009.02.012
        摘要：An All-Optical Networks（AON） provides a transparent optical channel for its users through wavelength routes,thus bringing about many security problems.Among others,network invaders often make use of their vulnerable points to interfere with the services and steal signals.This paper focuses on the security management related to the optical layer of AON and introduces,on the basis of the analysis of their security features,the three ways of malicious attacks that they may encounter and presents some solutions against different ways of attacks and analyzes and compares their advantages and disadvantages.  
        关键词：AON;networks security;attack;protection   
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      • Jiang Wei,Yang Junjie,Chu Fenghong
        Issue 2, Pages: 38-41(2009) DOI: 10.13756/j.gtxyj.2009.02.002
        摘要：The broadband Power Line Communication（PLC） technology determines the development orientation of the power line carrier communications.On the basis of the principle of the broadband PLC,this paper introduces two broadband modulation technologies that are mainly used in power line carrier communications,i.e.spread spectrum and OFDM,analyzes the principle of their resistance to interference and to multi-path effects and compares their advantages and disadvantages when they are applied in power line communications.Then,it continues to introduce several versions of the latest power line carrier chips and finally describes the current status of PLC and forecasts its market prospect.  
        关键词：OFDM;spread spectrum;PLC   
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      • Guo Changying1,Zhang Fang1,Yu Yanguang2
        Issue 2, Pages: 42-44(2009) DOI: 10.13756/j.gtxyj.2009.02.013
        摘要：The denoising of optical feedback self-mixing interferometer signals is studied by comparing the traditional digital filter method and Birge-Massart threshold wavelet method.The theoretical model of optical feedback self-mixing interferometer system is constructed and the denoising effects of the weighted smooth filtering,finite long-unit impulse response filter and the threshold wavelet method are compared by processing the simulated and measured waveforms.The results prove that the threshold wavelet method is better than the other two traditional filtering methods.  
        关键词：optical feedback self-mixing interference;signal denoising;wavelet transformation;Birge-Massart threshold   
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      • Chen Wei,Li Shiyu,Wang Yanliang,Lei Daoyu
        Issue 2, Pages: 45-46(2009) DOI: 10.13756/j.gtxyj.2009.02.014
        摘要：In this letter,we first design the waveguide structure of a large-mode-field double-cladding Photonic Crystal Fiber（PCF） and then fabricate a high numerical aperture and large mode-field Yb3+-doped double-cladding PCF for the first time in China by using the patent technologies with our own IPR.The Numerical Aperture（NA） of its inner cladding is as high as 0.65,the NA of its fiber core 0.06 and its effective mode-field area 1 465.7 μm2.As far as we know,this is the first report in China.  
        关键词：PCF;Yb3+-doped;double cladding;design;fabrication   
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      • Chen Jing1,Tan Xiaoling2
        Issue 2, Pages: 47-49(2009) DOI: 10.13756/j.gtxyj.2009.02.006
        摘要：On the basis of a compact two-dimensional frequency domain finite difference method with anisotropic Perfectly Matched Layers（PML） absorbing boundary conditions,the mode and dispersion properties of the octagonal Photonic Crystal Fiber（PCF） is investigated.The fundamental mode and the multimode cut-off properties of the octagonal and hexagonal PCFs are analyzed by using the effective area method and the phase diagrams of the non-finite mode,fundamental mode and multimode obtained.Their comparisons show that with the same filling fraction and air hole pitch,O-PCF has wider single mode operation region and is more apt to be used for dispersion compensation than H-PCF.  
        关键词：PCF;PML;finite difference frequency domain method;cut-off mode;effective area   
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      • Chen Liming1,Shao Ping1,Liu Yunli2
        Issue 2, Pages: 50-52(2009) DOI: 10.13756/j.gtxyj.2009.02.007
        摘要：Since the first submarine optical fiber cable in the world came out in 1985,it has been extensively constructed all over the world.With the advantages of large capacity,high reliability and outstanding transmission quality,it has played a vital role in the field of communications and especially international communications.This paper first gives a brief introduction to its technical requirements,then analyzes its typical structure and summarizes its key manufacturing techniques and the construction process,and finally points out the trend of its development.  
        关键词：submarine optical fiber cable;structure;technical requirement;construction;trend of development   
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      • Hu Xianzhi1,Xu Zhen2
        Issue 2, Pages: 53-56(2009) DOI: 10.13756/j.gtxyj.2009.02.008
        摘要：This paper reviews the latest research development in the developed countries in Plastic Optical Fibers（POF）,plastic optical fiber cables,photoelectronic devices,connecting methods and transmission test systems.Characteristic of low attenuation,broad bandwidth and cheap price,perfluorinated polymer graded index POF has gradually found applications in short-haul high-rate transport.In this paper,specific measures for reducing its attenuation and broadening its bandwidth are introduced and the optical cable structure,connecting methods and transceiver modules for the construction of POF transmission systems described.The transmission test results prove that POF is the optimum transmission medium for short-haul high-rate transport.  
        关键词：perfluorinated polymer;graded index;POF;communication system   
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      • Hu Shujuan1,Chen Shuwen1,Wu Ping1,Liao Qinghua1,Huang Yongzhen2
        Issue 2, Pages: 57-60(2009) DOI: 10.13756/j.gtxyj.2009.02.004
        摘要：A directional coupler is composed of multiple photonic crystal monomode waveguides placed in parallel and adjacent to each other.When the input optical field is symmetric to the incidence,its propagations in this system are numerically analyzed in accordance with the self-imaging principle.On the basis of this structure,an ultracompact multichannel,say 3-channel,beam splitter is designed and the optical field is transversely redistributed simply by symmetrically changing the refractive indexes of two dielectric rods in the coupling region,realizing the uniform or free distribution of the output energy.This kind of modulation is simple and more efficient.  
        关键词：photonic crystal waveguide;directional coupler;beam splitter;uniform energy distribution   
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      • Xi Congling
        Issue 2, Pages: 61-63(2009) DOI: 10.13756/j.gtxyj.2009.02.005
        摘要：On the basis of the gain characteristics of the Er-doped fiber in 1 550 nm,the simple structure of a tunable fiber grating laser is designed by using the fiber grating as the tuning device and its wavelength is tuned by changing the temperature of the fiber grating.What is more important is that the influences of different Er-doped fiber lengths on the laser output power are analyzed and tests are performed with fibers of different lengths of 10,20 and 30 m at 25 ℃,the results of which show that fibers of different lengths have different thresholds.  
        关键词：guided wave and fiber optics;ring-cavity fiber laser;Er-doped fiber laser;fiber Bragg grating   
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      • Song Zhiguo1,Wang Jing2,Li Xiao2,Yao Xiangyu2,Liu Wen2
        Issue 2, Pages: 67-70(2009) DOI: 10.13756/j.gtxyj.2009.02.001
        摘要：Improved on the basis of the ordinary Electronic Current Transformer（ECT） and characteristic of higher precision,lower power consumption and better functions,the novel ECT satisfies the requirements of digital substations.This paper successively introduces its general design,its constituent data collector at the higher voltage side and the Merging Unit（MU）at the lower voltage side and its power supply scheme.  
        关键词：ECT;data collector;MU;laser power supply   
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      • Wang Kuiru,Li Cheng,Zhang Jinglong,Zhao Dexin
        Issue 2, Pages: 3-5(2009) DOI: 10.13756/j.gtxyj.2009.02.022
        摘要：As the conventional fiber grating sensor network is poor in flexibility and mobility,we propose a novel fiber grating wireless sensor network,which integrates the merits of wireless communications and fiber grating sensors and design the node structure and the routing protocol Routing Table（RT） for this network in line with the actual application sceneries.In NS2（Network Simulator）,we compare it with Flooding protocol in delivery ratio,delay and power consumption,the results of which show that the RT protocol suits the new sensor network better.  
        关键词：fiber grating sensor;wireless sensor network;routing   
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      • Yu Junting1,He Hongye2
        Issue 2, Pages: 14-15(2009) DOI: 10.13756/j.gtxyj.2009.02.018
        摘要：Chromatic dispersion has become an enormous obstacle to the development of long-haul high-speed fiber-optic communications.So Dispersion Compensation Fibers（DCF） are usually used to solve this problem,but they are liable to great insertion loss and nonlinear effects.On the basis of analyzing the dispersion compensation principle of the chirped fiber grating,we propose to use it in multi-channel WDM systems so as to realize long-haul repeaterless transmissions,while overcoming the above-mentioned shortcomings.  
        关键词：chirped fiber grating;dispersion compensation;dispersion   
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      • Zheng Jie,Zhou Rikai,Ma Hongyong,Hu Qianggao,Jiang Shan
        Issue 2, Pages: 64-66(2009) DOI: 10.13756/j.gtxyj.2009.02.003
        摘要：Optical Switches（OSW） and Variable Optical Attenuators（VOA） are key components in fiber-optic communication systems and Micro-Electro-Mechanical Systems（MEMS） is a promising OSW technology.In this paper,a 1×2 MEMS OSW with VOA functions is presented,its theory introduced in detail and the formula for the calculation of the insertion loss is deduced in detail by using matrix optics.On the basis of designing the parameters of the C-lens,an OSW sample is made and compared with the calculations,the result of which indicates that this OSW has practical values.  
        关键词：MEMS;OSW;VOA   
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