最新刊期
卷 ， 期 4 ， 2010
- 摘要：A novel WDM-PON structure based on orthogonal FSK/ASK re-modulation scheme is presented in this paper.In the downstream direction,a FSK modulation technology based on phase-to-intensity modulation conversion is adopted to generate 40 Gbit/s FSK signals,while in the upstream direction,10 Gbit/s ASK signals are directly modulated onto the FSK signals to achieve orthogonal modulation format.The performances of the entire system are studied and simulation results show that this structure can satisfy the requirements for access network transmission and provides an option for the future high-rate access networks.关键词：PON;FSK;orthogonal modulation
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发布时间： - 摘要：A novel All-Optical Wavelength Conversion（AOWC）-based Hybrid WDM/TDM PON（HPON） architecture is proposed in this paper.The input dynamic range of the burst-mode AOWC module is extended by using an EDFA so as to meet the application requirements for the wavelength conversion of the uplink 2.5 Gbit/s of burst signals of the system.The principle of range extension is analyzed and verified by simulation.The experimental results indicate that the input dynamic range is extended from 5.5 dB to 29.8 dB at BER of 10-9.关键词：optical communications;HPON;burst-mode;AOWC;dynamic range
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- 73
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发布时间： - 摘要：In view of the disadvantages of the conventional P-cycle protection algorithms,e.g.long running time and low resource utilization ratio,this paper presents a novel heuristic algorithm,which takes redundancy as the evaluation criterion and,in combination with the unprotected link ratio,efficiently constrains the expansion of the P-cycles when there are few unprotected links so that highly efficient P-cycles can be calculated in only one step and the optical networks 100% protected.Simulation results obtained in the pan-European COST239 network and the New Jersey LATA network show that this algorithm can effectively reduce the number of the P-cycles to be configured,cut down the running time and improve the network resource utilization ratio.关键词：P-cycle;protection;survivability;optical network
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- 120
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发布时间： - 摘要：This article first describes the drawbacks of the present IP networks in carrying voice and video services and then presents the thoughts about solving their existing problems,and describes in detail the specific active protection measures for IP networks.Specifically,relevant network indexes are collected through the network monitoring center and once the quality index deterioration of the IP network equipment ports or links are found to exceed the tolerance threshold of voice services,relevant instructions will be issued to the IP network equipment to implement fast cutover of the links that fail to meet the voice or video service quality requirement.关键词：IP network;quality monitoring;recovery mechanism;active protection;latency;jitter
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发布时间： - 摘要：The model of a novel Optical Transport Network（OTN） architecture is set up in this paper,to which the signals from Ethernet clients are adapted by a new mapping procedure and transported over the model.It is proved by the comparison between the clock at the receiver end and the ideal clock that the new procedure has less effect on the OTN clock performance.This model and the resulted conclusion may help optical network system designers estimate and analyze the network clock performances and predict the possible effects of different mapping procedures on clock performances.关键词：OTN;clock performance;mapping procedure
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发布时间： - 摘要：With regard to fiber grating temperature sensor systems that are based on the tunable Fabry-Peort（F-P） filter method,effects of the transmission delay caused by cable length on the wavelength demodulation accuracy is theoretically studied.Numerical simulation results show that when the scan frequency of the demodulation system is 4 Hz,the error of the wavelength measurement for a certain length of optical cable caused by transmission delay is 7.911 pm/km,the corresponding temperature error is about 0.8 ℃/km,which is multiplied with the increase of the scan frequency.关键词：transmission delay;accuracy;fiber grating;demodulation system
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- 96
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发布时间： - 摘要：A hybrid TDM/WDM technology-based distributed fiber vibration sensing network perimeter is introduced in this paper.On the basis of fiber interference sensing technology,using a fiber Sagnac interferometer as a perimeter alerting unit and combining with the hybrid TDM/WDM technology for network communications,united perimeter alerting for 120 user units is achieved,which can be expanded to 256 users.关键词：hybrid TDM/WDM;fiber Sagnac interferometer;network perimeter;sensing network
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- 356
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发布时间： - 摘要：This paper first describes the principle of Brillouin Optical Time-Domain Analysis（BOTDA） technology and the dependences of Brillouin frequency shift on temperature and strain.Then it introduces in detail the current status of its research at home and abroad,research method,temperature,strain and spatial resolution and the dynamic range of measurement and analyzes the existing foreign commercially available BOTDA-based products and their specifications and the main problems with the BOTDA technology.Finally,it points out the areas of its applications and the trend of its development.关键词：BOTDA;Brillouin frequency shift;temperature;strain;spatial resolution
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- 1043
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发布时间： - 摘要：To develop a practical adaptive PMD compensation control module,a novel design scheme is presented and implemented,in which high performance floating-point DSP is used to focus on algorithm processing,EDMA for data transmission,FPGA for data acquisition and logic control.The hardware design,work process and software design for this module are introduced in detail and the employed Particle Swarm Optimization（PSO） algorithm is elaborated.In addition,its work and algorithm flowcharts are given.Experimental results indicate that this module produces a good compensation effect for second-order PMD and consumes less time than previous ones.关键词：PMD compensation;PSO algorithm;DSP;FPGA
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发布时间： - 摘要：In order to support the access of voice,video and data services,the dynamic bandwidth allocation algorithm for EPON need to provide services of different priorities with different quality of services and reduce the latency of real-time services,thus resulting in light load penalty.In respect to this problem,a multi-queue bandwidth allocation scheme is presented,i.e.optical network units request bandwidths for service with different priorities respectively and a prediction scheme is introduced.A specific algorithm is given and simulation is carried out.Simulation results show that this scheme can not only support multi-service access,but also fundamentally avoid light load penalty and further improve the QoS for services with high priorities.关键词：EPON;dynamic bandwidth allocation;light load penalty;QoS
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- 70
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发布时间： - 摘要：The Optical Burst Switching（OBS） network is a typical representative of all-optical packet switching networks.This paper studies the performances of the variable-burst-length-based OBS network,gives and analyzes parameters as the average load of bursts in the network for different traffic loads.In addition,it explains the relationship among average network latency,load of bursts and burst length when the set transmission rate is 10 and 40 Gbit/s respectively.The obtained results are supplementary to the theoretical study of OBS networks.关键词：optical burst switching（OBS）;load of bursts;latency
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- 59
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发布时间： - 摘要：With the continuously increasing demand for bandwidth,the traditional way of copper cable access cannot satisfy the user requirements and FTTx has become the direction of access network development.Passive Optical Network（PON） is the most up-to-date application technology for fiber integrated broadband access and Ethernet-based PON（EPON） has especially found operators’ favor because of its so many advantages.Taking a certain community as an example,this paper presents a solution for EPON and makes the relevant analysis.关键词：EPON;project design;residential community
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- 136
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发布时间： - 摘要：The voice quality evaluation methods for VoIP（Voice over IP） are introduced in this paper.It is necessary to monitor the VoIP voice quality by the study of these methods and enable it to keep a certain level of service.In this paper,the principle for the implementation of subjective and objective evaluation models is analyzed and the quantitative comparison results between their tests and between different objective evaluation model tests are given.关键词：VoIP;voice quality;PESQ;E-model
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- 107
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发布时间： - 摘要：As submarine cables applied in usually complicated environment are subject to water pressure,impact and subterranean flow,the resulted stochastic Polarization Mode Dispersion（PMD） has become a limiting factor for the system extreme transmission.In this paper,the effects of such external factors as lateral stress and bending on PMD are theoretically analyzed and simulation of the 4×2.5 Gbit/s communication system is performed in accordance with the actual work conditions of the cable,taking 3 dB as the power redundancy.Simulation results show that when the communication system works normally,the PMD coefficient does not exceed 1.8 ps/km.In order to avoid PMD compensation,the lateral stress is not to be greater than 8.9 N/m when the bending radius is 0.3 m.关键词：stress;bending;polarization mode dispersion（PMD）;birefringence
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- 45
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发布时间： - 摘要：With the development of fiber-optic technology,we have seen the pluralistic trends of optical fiber cable development.As one of the special power cables,OPGW cable has been rapidly developed and applied in the optical communications for electric power systems because of its unique advantages.This paper first introduces its concept and feature requirements.Then,it describes in detail the precautions for its design,construction and applications in power systems.Finally,in connection to the development plan for Xuchang electric power communication network,it illustrates its present application status and future development in Xuchang electric power system,which has a certain value of reference for the engineering design and construction of electric power systems.关键词：OPGW;power optical transmission network;cable installation
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- 314
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发布时间： - 摘要：In typical Micro Electro-Mechanical Systems（MEMS）-based Wavelength Selective Switches（WSS）,bi-axial MEMS micro-mirror technology is usually used to achieve wavelength cutover and optical power attenuation.In this paper,the mechanism for the cause of the so-called "rabbit ear" phenomenon in MEMS-based WSS in power attenuation is theoretically studied and experimentally verified,which shows that the explanation by using the diffraction theory is in good agreement with the experimental results.关键词：WSS;"rabbit ear";MEMS
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- 104
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发布时间： - 摘要：As a transmission type filter,phase-shifted fiber Bragg grating can be widely applied in the fields of optical communications and sensing.This paper introduces a novel micro-structured phase-shift fiber grating that is based on fiber cladding etching technology,analyzes by using the fiber double-cladding theory the effects of the cladding etching depth and the environmental refractive index on the effective refractive index of the fundamental mode of the fiber core and the correlation between the etching depth,width and location with the reflective spectrum of the micro-structured phase-shift fiber grating on the basis of combining the resonance theory and the transfer matrix method.关键词：phase-shifted fiber grating;Fabry-Perot structure;double-clad single-mode fiber;transfer matrix method
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- 192
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发布时间： - 摘要：A Cascaded Long-Period Waveguide Grating（CLPWG）filter is proposed,in this paper,which is directly written on the Er-Yb co-doped phosphate glass waveguide.The proposed filter consists of different filtering unit cells with different resonant wavelengths and bandwidths.Its transmission characteristics are theoretically studied and the effects of its transmission spectrum on flattening the Amplified Spontaneous Emission（ASE） spectrum of the Er-Yb co-doped phosphate glass waveguide amplifiers discussed.关键词：integrated optics;CLPWG;Er-Yb co-doped phosphate glass
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- 110
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发布时间： - 摘要：An optical transceiver module is a high-tech active device,which is low in power consumption and small in size.Its emergence has promoted the development of optical transmission systems,so its performance test is of great significance.In this paper,the performances of an optical transceiver module are tested on an Automatic Test System（ATS） controlled by LABVIEW software.ATS device connection diagram is first designed and its principle explained.And then OC3-IR module is tested in three different temperatures by using LABVIEW.The test results show that the test is a success.关键词：ATS;optical transceiver module;LABVIEW software;test
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发布时间： - 摘要：Random access is a very important process in the establishment of uplink synchronization and connection between the UE and base stations in the mobile communication system.This article mainly studies the design of TD-LTE uplink random access technology.Considering its universal adaptability,it discuses the competition-mode-based random access process on the basis of the scenarios and types of its applications and gives a detailed analysis of its specific procedures and implementation schemes.关键词：LTE;random access;HARQ
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- 373
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发布时间： - 摘要：The non-access layer of network equipment has the core network capabilities and EPS Mobility Management（EMM） is an important entity of its MM sub-layer,which mainly provides MM functions.As a common test method for high-level communication protocol software,conformance testing mainly uses software SDL and TTCN suite4.0 that integrates the functions of simulation,development and testing as a development tool in combination with the Message Sequence Chart（MSC） generated from the co-simulation by SDL and TTCN to complete the test,so as to achieve the purposes of error tracking and error code/parameter modifications.关键词：EMM;TD-LTE;TTCN;conformance testing
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