最新刊期
卷 ， 期 5 ， 2008
- 摘要：The modulation and demodulation methods of the optical Differential Quadrature Phase-Shift Key（DQPSK） are briefly introduced,including a necessary illustration of its precoding.Its back to back system is established by using Matlab,the optical power spectra and eye diagrams in different DQPSK modulations obtained and their simulation results verified Finally,NRZ-DQPSK is compare with RZ33-DQPSK.关键词：optical fiber communication;optical DQPSK;modulation format
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- 830
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发布时间： - 摘要：With the rapid development of the optical transmission technologies,the signal transmission rate has exceeded Gbit/s,so the analysis of high-speed channel simulation has become one of the key links in the success of the system development.This paper briefly introduces the basic principle and methods of Hspice simulation,discusses in detail the high speed serial channel simulation method based on Hspice software and presents several key links that have a bearing on high-speed channel performance through the comparison between the simulation eye diagrams and the methods for the improvement of channel performance.关键词：Hspice simulation;eye diagram;high-speed serial channel
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- 143
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- 1
发布时间： - 摘要：As a new multi-phase modulation keying,optical Differential 8-Phase Shift Keying（8DPSK） is a subject in the most advanced research field of optical communications.This paper introduces the modulation format principle of optical 8DPSK and the way of its modulation and demodulation.With the help of Matlab,we simulate 8DPSK modulation and demodulation;draw the spectrum diagram and eye diagram and make detailed analysis of the RZ-8DPSK signals with a duty circle of 0.5,modulate and demodulate 64 PRBS signals,draw the optical pulse sequence diagram,phase-difference diagram and the electrical signal sequence diagram after balanced reception.关键词：optical 8DPSK;phase modulation;fiber-optic communication
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- 317
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- 5
发布时间： - 摘要：On the basis of the system architecture of the GMPLS-based optical burst switching（OBS） networks,this paper studies the way of introducing GMPLS into OBS and making them work with efficiency and in coordination.It focuses on the key technologies and solutions of GMPLS-based OBS networks and presents new and proper methods especially for dealing with the conflicts between the Burst Data Packets（BDP）.Finally,it points out the direction of the further study of the GMPLS-based OBS network.关键词：GMPLS;OBS;burst data packet;conflict mechanism
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- 92
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- 3
发布时间： - 摘要：This article designs and simulates a kind of Trellis Coded Modulation（TCM） system,in which the convolutional code is combined with Overlapping Pulse-Position Modulation（8OPPM）.This system can improve the OPPM system performance at no penalty in bandwidth utilization ratio.The simulation results indicate that the system can obtain 1～3 dB coding gain in comparison with the uncoded Pulse Position Modulation（4PPM）.关键词：OPPM;TCM;convolutional code;bandwidth utilization ratio;coding gain
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- 89
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- 1
发布时间： - 摘要：In the evolution of the optical transport network to the packet transport network,one of the main concerns of the operators is the interworking between networks.This paper briefly introduces the architecture of the MPLS-TP packet transport network,analyses the multilayer network structure based on MPLS-TP packet transport network in the coexistence of various types of transport networks and focuses on the discussions about the implementation schemes for the interworking between MPLS-TP packet transport network and IP/MPLS network and among SDH/MSTP networks themselves.关键词：PTN;MPLS;interworking
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- 180
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- 5
发布时间： - 摘要：In view of the service requirements of the next generation optical networks,we study some service-oriented Routing and Wavelength Assignment（RWA） issues in ASON infrastructure and present the concept of service-oriented RWA in conformity with the evolution of optical networks to service networks and make preliminary investigations in routing and wavelength assignment respectively.In the service-oriented network environment,it is necessary to offer differentiated services and study the priority-based RWA algorithm in order to achieve this aim and present the block diagram for the implementation of differentiated services-oriented RWA.关键词：ASON;service optical network;RWA;differentiated service
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- 95
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- 1
发布时间： - 摘要：In this paper,a novel predicted Dynamic Bandwidth Allocation（DBA） algorithm for QoS guarantee in EPON systems is proposed,which combines multiple subcycles into one supercycle.In the supercycle,the bandwidths for different levels of services are predicted and allocated in the subcycles with reference to the predicted values.Access Management（AM） modules are added to maintain stable QoS.Experimental results show that by using this algorithm,the bandwidth availability and delay can be ensured for different levels of services and still more stable QoS provided.关键词：EPON;DBA;delay;QoS
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- 104
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- 3
发布时间： - 摘要：This paper first gives a brief introduction to the network management system of GPON and then analyzes the functions of ONT Control/Management（C/M） module according to the protocol stack for C/M planes.On this basis,it designs the overall structure of ONT C/M module,which consists of four functional modules: basic ONT C/M module,senior C/M implemented by OMCI,local Ethernet network management interface module and panel control.Finally,it completes their analysis and design.关键词：GPON;C/M;ONT C/M module
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- 77
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- 5
发布时间： - 摘要：As current deployment plans for IPv6 campus network employment are mostly at their initial stages,this paper studies the frameworks at various stages from IPv4 campus network to pure IPv6 campus network.On the basis of the basic services of IPv6,it investigates the possible framework plans at various stages from campus networks with IPv4 as the mainstream and coexistence of IPv6 with IPv4 to pure IPv6 campus networks.关键词：deployment;coexistence;framework;campus network
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- 350
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- 16
发布时间： - 摘要：On the basis of the practical conditions of the local transmission access network in Yichang city,this paper describes in detail its planning and transformations for the advent of the early 3G.Specifically,it discusses the network structure planning of the network lines and the equipment update for the support to the service development and describes the rational arrangement of the network switching and the effective applications of Digital Cross Connect（DXC） in the integration of the transmission resources.关键词：3G service;DXC;transmission access network
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- 32
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- 0
发布时间： - 摘要：In view of the structural features of the distributed antenna system,a RoF-based solution for digital intermediate frequency remote is proposed.The design of the digital down converter module is given via FPGA in consideration of resource saving and performance improvement.The analytical and simulation results show that this design contributes to the reduction of resource consumption and satisfaction of the module performance with the requirements of the future broadband wireless communication system.关键词：Distributed Antenna System;MIMO;digital intermediate frequency remote;CIC filter;poly-phase decimate filter
- 3
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- 193
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- 3
发布时间： - 摘要：In this letter,the waveguide structure of Dispersion Compensation Fiber（DCF） is designed and a kind of high-performance DCF fabricated.The test results show that it has fairly large negative dispersion in the wavelength range of 1 525 nm-1 625 nm,e.g.-141 ps/nm/km at 1 545 nm.Wideband dispersion compensation modules（DCM） are manufactured with this DCF.When G.652 fiber transmission links are compensated by this DCM,the residual dispersion in C-band is smaller than 5.0 ps/nm and the dispersion slope of the C band are also compensated by 100%.关键词：DCF;module;fiber-optic telecommunication;WDM
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- 92
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- 3
发布时间： - 摘要：Compared with the conventional polarization maintaining fiber（PMF）,polarization maintaining Photonic Crystal Fiber（PM-PCF） has such advantages as higher birefringence and lower temperature polarization coefficient.This article introduces an experiment,in which PM-PCF is used as the PMD compensation element for dynamic PMD compensation and verifies the performances of the compensation system by analyzing the experimental results.关键词：PMD;PCF;dynamic compensation
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- 139
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- 2
发布时间： - 摘要：The numerical simulation and analysis of the dispersion properties of a novel hexagonal core Photonic Crystal Fiber（PCF） are performed by using the multipole method.The study finds that dispersion compensation fibers with high dispersion value at wavelength around 1.55 and negative dispersion slope transmitted in single mode at short-wavelengths can be flexibly designed by changing the air hole diameter of the 1st cladding and the air hole pitch.The numerical simulation and analysis show that this type of PCF will find extensive applications in dispersion compensation fibers.关键词：PCF;dispersion compensation;multipole method;hexagonal core
- 2
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- 147
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- 2
发布时间： - 摘要：A low-cost reconfigurable optical add/drop multiplexer（ROADM） with system upgrade capability and dynamic gain equilibrium is studied.This module consists of planar Arrayed-Waveguide Grating（AWG）,Switch Integrated Variable Optical Attenuator（SiVOA）,circulator,tap PD,coupler and isolator.The flexible application of SiVOA contributes to the realization of the two-way transmission of wavelengths and module cost reduction.Optical signals with single or multiple wavelengths can be added/dropped at any add/drop ports with power adjusted at random by regulating SiVOA.The fundamental work principle and index test results of the new module are given.关键词：ROADM;SiVOA;AWG
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- 94
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- 1
发布时间： - 摘要：A novel Photonic-Crystal-Waveguide（PCW）-based optical power splitter is designed on the basis of the waveguide directional coupling principle.The Finite-Difference Time-Domain（FDTD） method is adopted to make the numerical analysis of its optical waveguide transmission properties.The results show that the dispersion curves of the eigenmodes intersect among themselves;the splitter is shorter than the conventional ones,the incident energy to the optical power splitter is equally splitted to the output ports and the optical wave transmissivity is as high as 95%.These excellent properties are extremely useful in manufacturing photoelectronic devices with large bandwidth,high transmissivity and compact structure.关键词：PCW;FDTD;directional coupling;multimode interference（MMI）
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- 222
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- 1
发布时间： - 摘要：For simultaneous distributed measurement of temperature and strain based on Brillouin scattering in optical fibers,there are mainly three effective ways: measuring the Brillouin intensity and Brillouin shift simultaneously,measuring two different Brillouin shifts and monitoring the temperature and strain based on the Raman scattering and Brillouin scattering.In this paper,the principles of these methods have been discussed thoroughly.Two schemes for Brillouin distributed sensing using direct detection and heterodyne detection are studied and a performance and cost comparison between them is made.Finally,a sensing scheme capable of realizing simultaneous measurement of temperature and strain with high accuracy is presented.关键词：BOTDR;temperature;strain;Landau-Placzek ratio
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- 400
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- 3
发布时间： - 摘要：Fiber Bragg Gratings（FBG） have extensive applications in optical communication systems because of its unique optical properties and flexible designs,including optical pulse compression,alloptical switch,alloptical multiplexer/demultiplexer,dispersion compensator and optical storage.In this paper,an analysis of the applications of FBG in optical pulse compression is specifically made and the structures,principles and performances of several kinds of FBG based compressors reviewed in detail.关键词：FBG;optical pulse compression;Group Velocity Dispersion（GVD）;SelfPhase Modulation（SPM）
- 2
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- 195
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- 2
发布时间： - 摘要：In this paper,the importance of the precision and stability of downlink synchronization in the TD-SCDMA repeater applications is first introduced.Then,on the basis of the simulation results of two different synchronization algorithms for eigenvalue and demodulation achieved with the Advanced Design System（ADS）,their anti-jamming performances are compared.Finally,their advantages and disadvantages and applicability are analyzed and suggestions for improvement presented on the basis of the statistical simulation results and their practical applications in repeaters.关键词：TD-SCDMA;repeater;downlink synchronization;precision
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- 91
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- 1
发布时间： - 摘要：This paper studies the Random Beam-Forming（RBF） algorithm in MIMO systems.The simulation results show that with the increasing number of the users,the RBF technology can be used to obtain from the minimum feedback the same throughput as the coherent beam-forming technology,and also the multi-user diversity gain and multiplexing gain of the downlink in the slow fading channels of the MIMO system.关键词：MIMO;RBF;water-filling principle;proportional fairness
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- 234
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- 8
发布时间： - 摘要：Among multiple Wireless Sensor Network（WSN） hierarchical routing protocols,Low Energy Adaptive Clustering Hierarchy（LEACH） is a fairly popular one,but it does not take into account the energy status of each node in the network,and if and when the optimum number of clusters is fixed,it will not be changed in the entire network communication period,thus it is impossible to enhance the network lifetime more effectively.Thus,on the basis of LEACH protocol,an improved Energy Efficient Cluster Routing Protocol（EECRP） is proposed.The simulation results show that comparing with LEACH,EECRP has much better energy efficiency and prolongs the lifetime of WSN.关键词：WSN;LEACH;clustering;system lifetime
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