最新刊期
      卷 ， 期 2 ， 2005
      • LIU Wen,MAO Qian
        Issue 2, Pages: 1-4(2005) DOI: 10.13756/j.gtxyj.2005.02.001
        摘要：The paper describes popular ways to realize the dynamic ROADM （reconfigurable optical add/drop multiplexing） module at first. Then a simplify ROADM module and network architecture is proposed, and the possible applications in transmission networks are discussed. This solution can improve the equipments utilization factor, partly solving the problems of the peak time communications block （jam） among nodes. This paper also provides a way to realize the dynamic traffic re-arrangement between rings. The ROADM module suggested here has advantages of low cost and low interfere with other signals in the same networks.  
        关键词：ROADM（reconfigurable optical add/drop multiplexer）;tunable laser;network architecture;metropolitan networks   
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      • XIONG Gui-lan,WANG Long-shui
        Issue 2, Pages: 5-7(2005) DOI: 10.13756/j.gtxyj.2005.02.002
        摘要：Pointer adjustments bring 8 bit, or even 24 bit jitter in synchronous digital hierarhy （SDH）. In order to smooth the jitter, this paper presents a digital processing method, self-adaptive prognostication method, which can be applied as a preliminary processing method to regenerate the fourth order （E4） clock in SDH. This paper uses the example of regenerating the fourth order （E4） signal from STM-1 to introduce in detail the application of this method and its performances.  
        关键词：SDH;pointer adjustment;justification;jitter;self-adaptive prognostication   
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      • HAI Zeng-qiang,　MAO Qian
        Issue 2, Pages: 8-10(2005) DOI: 10.13756/j.gtxyj.2005.02.003
        摘要：Intelligence is one of the key points in the study area of optical networks. LCAS can increase the intelligence of SDH network, reduce the waste of bandwidth and increase the robustness of SDH network. In this paper we discussed the principle of link capacity adjustment schemes and the dynamic bandwidth distribution process, and analyzed the generation and transfer mode of the sink member status.  
        关键词：link capacity adjustment schemes（LCAS）;virtual concatenation（VC）;dynamic bandwidth allocation（DBA）   
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      • LUO Zhi-hui,WANG Long-shui
        Issue 2, Pages: 11-13(2005) DOI: 10.13756/j.gtxyj.2005.02.004
        摘要：The timing synchronization is for physical layer’s demand in telecommunication transmission networks, while the time synchronization is implemented by network time protocol in application layer, it meets application layer’s need in Internet networks, they are quite too different in structures, implementations and functions.  
        关键词：timing synchronization;synchronization status message;time synchronization;network time protocol   
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      • ZHANG Pin-chun,AO Fa-liang,GONG Xiao-yun,WAN Zhao-hui
        Issue 2, Pages: 14-17(2005) DOI: 10.13756/j.gtxyj.2005.02.005
        摘要：Firstly, this paper tried to put forward the definition of object to process of network node interface （NNI） and the layering model frame of interface, then gave an analysis of the relation between NNI and other models on control plane, finally, some new problems about the development of NNI interface be discussed.  
        关键词：ASON;GMPLS;I-NNI   
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      • ZHANG Ding-chun,He Dui-yan,Chen Xuan
        Issue 2, Pages: 18-20(2005) DOI: 10.13756/j.gtxyj.2005.02.006
        摘要：The quality of service （QoS） is of great importance to the next generation IP over WDM network. As a new optical switching technology, the labeled optical burst switching （LOBS） must support QoS. This paper presented the features of LOBS network, reviewed and summarized the existing QoS schemes for OBS network, discussed the QoS criterion in LOBS network.  
        关键词：QoS;OBS;LOBS;MPLS;GMPLS   
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      • LI Yue,WANG Long-shui
        Issue 2, Pages: 21-22(2005) DOI: 10.13756/j.gtxyj.2005.02.007
        摘要：Squeeze in adjustment and pointer adjustment are two main technologies which can be adopted by SDH transmission systems.The implement principle,characteristics and the interrelation of these two technologies are described. The waiting period jitter analysis and the jitter-removal technique are also given.  
        关键词：SDH;jitter;pointer adjustment;desynchronizers;squeeze in adjustment   
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      • HU Wen-juan~1,GUI Hou-yi~2,HUANG Ben-xiong~1
        Issue 2, Pages: 23-25(2005) DOI: 10.13756/j.gtxyj.2005.02.008
        摘要：To begin with, this paper described the basic conception of all optical network （AON）, Then it presented the key technologies and development trends of AON. Lastly, the paper described the challenges that AON faces.  
        关键词：AON;OXC;OADM   
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      • HUANG Xu-xi,YOU Song,WAN Hai-rong,CHENG You-qing
        Issue 2, Pages: 26-29(2005) DOI: 10.13756/j.gtxyj.2005.02.009
        摘要：With the application scale enlarged, the effective management of Ethernet swithch became an important question. The technology of switch group management is a good solution. Based on Group Management Technical Specification for Ethernet Switches drafted in homeland, this paper introduces design and implementation of switch group management. Combined with the problems in practice, the strategy of group management is discussed.  
        关键词：switch concatenation;stacking;group;topology collection;SNMP   
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      • SUN Hai-jin,ZHU Na,ZHOU Nai-fu
        Issue 2, Pages: 30-34(2005) DOI: 10.13756/j.gtxyj.2005.02.010
        摘要：In this paper, the distributed method of dynamic routing and wavelength assignment （RWA） based on ant colony algorithm is brought forward in wavelength-division multiplexed optical networks. The routing choice and wavelength assignment are implemented at one time combining with layer model. Simulation result indicates that, compared with shortest algorithms, the ACO algorithm can achieve lower blocking rates and rational assignment of wavelength resource, and decrease the communication overhead of current large networks which vary frequently.  
        关键词：RWA;ant colony algorithm;simulation;blocking rates   
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      • WANG Yu-hui,HUANG Chuan-he,CHEN Ying
        Issue 2, Pages: 35-37(2005) DOI: 10.13756/j.gtxyj.2005.02.011
        摘要：In the PDMA system of mobile Internet,the users can access Internet through simple IP or mobile IP. A great challenge the PDMA faces is how to implement the function of AAA （authentication, authorization and flow pattern-based accounting） based on RADIUS protocol. this paper offers a design scheme which support two layered protocols of micro-mobility and macro-mobility to carry out the AAA mechanisms processing respectively and realize the effective coordination between the AAA mechanisms of two layers. This scheme has achieved good results in the practical operation of a certain base of PLA.  
        关键词：PDMA;MPPP;mobile IP;AAA   
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      • XIE You,WANG Ya-min
        Issue 2, Pages: 38-41(2005) DOI: 10.13756/j.gtxyj.2005.02.012
        摘要：The interaction between femstosecond optical pulses under Raman self-frequency shift effect and the suppression of it are studied by using numerical simulation. The study results show that the existence of Raman effect makes the interaction between fs pulses different from that of conventional ps pulses. In the early stage, the pulses will attract each other, then they will keep the state of repulsion, the pulse spacing will increase along with the increase of the propagation distance, the pulse drift in propagation and the pulse energy exchange will take place, the propagation distance will remarkbly decrease and the communication quality will seriously worsen. The interaction between pulses under Raman effect can be suppressed by the use of synchronous amplitude modulation in combination with nonlinear gain and filter techniques.  
        关键词：femtosecond（fs）;optical pulse;self-frequency shift;interaction   
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      • CHEN Long
        Issue 2, Pages: 42-45(2005) DOI: 10.13756/j.gtxyj.2005.02.013
        摘要：This paper analyzed the threat of security to the network information system, elaborated the security technique policy for network information system, gave an overall design scheme which can completely and effectively achieve the aim of realization of the network system security.  
        关键词：network information system;information security;collectivity design;technique policy   
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      • Issue 2, Pages: 45-66(2005)
          
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      • LU Xiu-juan,FAN Qi-peng
        Issue 2, Pages: 46-49(2005) DOI: 10.13756/j.gtxyj.2005.02.014
        摘要：Input queued （IQ） switch architectures with virtual output queues （VOQ） can scale up to very high speed. With the increase in density of VLSI, buffering at Crossbar cross points for one cell or packet become possible. CICQ switches have simple schedulers and result in lower delay than IQ switches.  
        关键词：switch fabric;scheduling algorithm;matching   
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      • LIN Pei,HU Yu,ZHOU Xiu-li
        Issue 2, Pages: 50-52(2005) DOI: 10.13756/j.gtxyj.2005.02.015
        摘要：Suppression of multiple access interference （MAI） is one of the key technologies in wireless optical CDMA systems. The cause of generation of MAI is analyzed and the suppression methods of MAI are given: optical hard limiter （illustrated in an OCDMA system with prime code） and multiple user detection （MUD,illustrated in an OCDMA system with 2-dimensions code）. Results show that optical hard limiter technology can only suppress MAI partly while MUD can eliminate MAI effectively. MUD technology is proposed as a good scheme to eliminate MAI in wireless OCDMA systems.  
        关键词：wireless optical CDMA;multiple access interference;multiuser detection;optical hard limiter   
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      • HUANG Jian-fei,WU Jian-xue
        Issue 2, Pages: 53-55(2005) DOI: 10.13756/j.gtxyj.2005.02.016
        摘要：The development of DWDM presents ever higher requirements for amplifier. The emergence of MW-FRA broke the limit of bandwidth of amplifier, while it put forward a new problem of gain flatness control. This paper analyzed the power coupling equation of pump and signal in MW-FRA, derived its gain formula, then optimized the pump power using inheritance arithmetic, and achieved an improvement on flatness of gain spectrum.  
        关键词：multiple wavelengths fiber Raman amplifier;power optimization;coupling equation;inheritance arithmetic   
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      • LIU Jun~
        Issue 2, Pages: 56-58(2005) DOI: 10.13756/j.gtxyj.2005.02.017
        摘要：This paper introduces a novel TFF （Thin Film Filter） optical WDM based on multlevel equalization. The device presents low insertion loss and good uniformity. Having more excellent performances than that of AWG, the TFF technology has become the leading technology for fabrication of DWDM device.  
        关键词：multilevel equalization;WDM;TFF;low insertion loss   
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      • MA Yu-hong,SUN Jun-qiang
        Issue 2, Pages: 59-61(2005) DOI: 10.13756/j.gtxyj.2005.02.018
        摘要：This paper introduces the relationship between the refractive index of nematic liquid crystal and applied voltage,as well as temperature. For the application of liquid crystal Fabry-Perot filter （LC-FPF） in DWDM system, a central wavelength automatic calibration unit is designed and its principle, detailed optical and electric circuit is illustrated. The effect of compensation on temperature drift of the unit is also analysed by calculation example.  
        关键词：filter;liquid crystal;Fabry-Perot interferometer;DWDM   
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      • YAN Chang-ling,LU Ping,LIU De-ming,WU Yue-xiang
        Issue 2, (2005) DOI: 10.13756/j.gtxyj.2005.02.019
        摘要：A simple and practical CWDM device was proposed, 8 multilayer thin-film-filters were placed in series to demultiplex 8 channel 20 nm spaced optical signals, behind these multilayer thin-film-filters there were 8 GRIN lenses and 8 fibers were arranged in two array-pairs to receive those demultiplexed signals。Test results showed that the performances of our device were satisfactory.  
        关键词：CWDM;multilayer thin-film-filter;GRIN lens;demultiplexer   
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      • ZHANG Jin-sheng,CAO Yi-le,ZU Hong-ye,YU Li,YANG Bo-jun
        Issue 2, Pages: 64-66(2005) DOI: 10.13756/j.gtxyj.2005.02.020
        摘要：In the high rate of optical communications system, the selection of optical source is very important. In this paper, the nonlinear transmission properties of fiber ring mirror is analyzed, and the principle of generating ultrashort-pulse using fiber ring mirror is discussed.  
        关键词：fiber ring mirror;self-phase modulation;passive mode-locking   
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      • MA Kun~
        Issue 2, Pages: 67-70(2005) DOI: 10.13756/j.gtxyj.2005.02.021
        摘要：This paper firstly calculated the diffraction characteristics of Gaussian beam baffled by a blade of the optical attenuator using Fourier transform, gave an approximate expression of diffracted beam’s intensity distribution. Then the paper draw an image of energy distribation of diffracted beam according to the expression, measured the diffracted beam’s intensity distribation of the （collimator’s） out comming beam having passed the blade, compared the calculated and measured results, and lastly, had a discussion on these results.  
        关键词：variable optical attenuator;Gaussian beam;diffraction   
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