最新刊期
卷 ， 期 4 ， 2013
- 摘要：As the transmission capacity of the existing quadrature modulation Optical Label Switching（OLS）systems is small and the crosstalk between label and payload is large,a novel quadrature modulation optical label stream encoding scheme with Polarization Multiplexed（POLMUX）-Carrier Suppressed Return to Zero（CSRZ）-Differential Quadrature Phase Shift Keying（DQPSK）as payload and Duobinary（DB）as label is proposed.The study results show that the system reaches the maximum transmission distance of 1 380 km when BER = 10-9,the receiver sensitivity of payload and label are-4.364and-4.268dBm respectively,the transmission power penalties of both payload and label do not exceed 1.8dB and the power penalty of payload carrying label does not exceed 0.8dB.关键词：POLMUX;CSRZ;DQPSK;DB;forward compensation;extinction ratio
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发布时间： - 摘要：For correct identification of current systems prior to dual-mode ONU registration,this paper presents two switching methods.In relation to the possible switching conditions for dual-mode ONU,it selects a switching method appropriate for the current switching scenario and designs and realizes an ONU automatical identification for current GPON/EPON systems,fascilitating hybrid deployment of access systems and providing an option for the convergence of the two technologies.关键词：dual-mode ONU;mode switching;EPON;GPON
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发布时间： - 摘要：In order to avoid the huge power penalty caused by nonlinear effects and polarization mode dispersion,this paper studies the technologies for polarization-based encoding.It proposes a triple-photoelastic-modulator（triple-PEM）-based polarization information acquisition method,which overcomes the shortcomings of the existing methods,such as inability to use array detector to effectively collect and modulate higher frequencies,and presents the MATLAB simulation and experimental results.These results verify its theoretical and practical feasibility.关键词：Stokes parameter;difference frequency modulation;polarization measurement;polarization encoding
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发布时间： - 摘要：For the modulation mode identification for OFDM subcarrier signals,ajoint recognition algorithm with high-order moments and high-order cumulants combined is proposed.This algorithm first distinguishes MPSK（M =2,4）,64QAM and 16QAM by using high-order moment-based feature and then distinguishes BPSK and QPSK by using high-order cumulant-based feature.Theoretical derivation and analysis indicate that this algorithm is insensitive to multipath fading and AWGN.Computer simulation results show that the proposed algorithm has high recognition performance under the multipath channel condition.关键词：OFDM;subcarrier;high-order cumulant;high-order moment;modulation identification
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发布时间： - 摘要：In this paper,we carry out an in-depth study on the Bill of Material（BOM）cost of the Optical Network Terminal（ONT）equipment of Gigabit-capable Passive Optical Network（GPON）systems and theoretically determine that Bi-directional Optical Subassembly（BOSA）on board is the optimum scheme.Then we introduce its technical difficulties and solutions and give the verification results of the hardware specifications,e.g.Electro-Magnetic Compatibility（EMC）and optical interface,which show that this scheme meets all the specifications of GPON ONT equipments under the premise of reduced cost.关键词：GPON;ONT;cost reduction;BOSA on Board（BOB）
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发布时间： - 摘要：In recent years,with the establishment of power system information disaster recovery centers,still higher requirements are placed on the clock synchronization for electric power business and the clock synchronization network plays a vitally important supporting role for the electric power communication network.This paper explains the necessity of the OTN support to clock synchronous transport when SDH networks are gradually replaced by OTN equipment deployed in large scales in power communication networks in the future.On the basis of analyzing the synchronization technology,it proposes a unified OTN+ PTN-based synchronous network model and conducts the relevant system tests.The results show that this networking mode satisfies the synchronization requirements of the electric power business.关键词：synchronization network;IEEE 1588standards;OTN
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发布时间： - 摘要：This paper analyzes the issue of multi-fault location in optical networks by using the fuzzy clustering theory and builds up its fuzzy clustering model.Then it performs fault location on the basis of the expert system obtained from the fuzzy clustering algorithm and the membership function formula between alerts and faults thus determined.Finally,it performs multi-fault location simulation experiments in optical mesh network topology and obtains the comparison charts of success rate in fault location and time performance.The experimental results show that the fuzzy clustering algorithm can locate faults fast and efficiently.关键词：fuzzy clustering;optical network;multi-faults;fault location
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发布时间： - 摘要：Taking Zibo Yuezhuang 220kV supporting communication project as an example,this paper introduces the development of electric power optical communication networks in Shandong and presents a communication application program by the aid of the combination of the provincial Optical Transport Network（OTN）circuit with the regional SDH and Packet Transport Network（PTN）circuits,enhancing the substation information transmission channels.关键词：IP service;PTN;OTN;SDH
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发布时间： - 摘要：In order to find the entry point of the applications of current quantum technologies in practical systems,this paper studies and analyzes the main technologies for current quantum communications and specially makes a theorectical analysis of the development and maturity of Quantum Key Distribution（QKD）-related protocols.Considering the constraints of the existing quantum device technologies,it concludes that the decoy state-based BB84protocol is the most mature QKD protocol and that quantum secure direct communication,quantum teleportation and other technologies are the the direction of quantum communication development.关键词：quantum communication;single photon;BB84 protocol;entangled state;QKD
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发布时间： - 摘要：In order to develop an anti-bending optical fiber for Fiber To The Home（FTTH）,a novel micro-structured optical fiber with 12air-holes around its silica core is designed and fabricated in this letter.This fiber has good anti-bending performance and is well compatible with G.652Dfibers.When the bending radius is 2.5mm,its additional bending loss at 1 550nm is less than 0.10dB and its splice loss with G.652Dsingle-mode optical fiber is less than 0.15dB.关键词：micro-structured optical fiber;FTTH;anti-bending
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发布时间： - 摘要：A novel Single-Polarization Single-Mode Photonic Crystal Fiber（SPSM-PCF）with squeezed hexagonal air holes array is proposed and the regular pattern of its confinement loss characteristics changes with the structural parameters is investigated by using a full-vector Finite Element Method（FEM）with a Perfect Matched Layer（PML）as the boundary condition.Numerical simulation results indicate that the confinement loss of the fast-axis mode is large whereas that of the slow-axis mode decreases with the increase of the number of the air-hole rings Nr,e.g.they are 4.534×10-4,2.236×10-5,9.597×10-6 dB/m at 1.550!m when Nr=6,8,10respectively.As the fast-axis mode is fast attenuated within a short length of fiber,a SPSM-PCF with the slow-axis mode only and the confinement loss less than 0.1dB/km is obtained.关键词：PCF;full-vector FEM;avoided-crossing effect;SPSM
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发布时间： - 摘要：Highly influenced by filler materials with high refractive index,PBG fibers with high-index rods are very sensitive to such parameters as temperature and applied electric field.In order to obtain temperature sensing of photonic crystal fibers with high sensitivity,we propose a method,in which temperature-sensitive liquid is injected into the air holes of their claddings,and simulate the method by using the full vector finite element method.The results indicate that with the increase of temperature,the effective refractive index decreases,the mode field area increases,and the temperature sensitivity can be as high as 20.2dB/m/℃.关键词：PBG fiber with high-index rod;temperature sensing;optical fiber sensing
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发布时间： - 摘要：In this paper,we present an optical add-drop filter design on the basis of the coupling properties between waveguide and the ring resonators in photonic crystal.We investigate the normalized transmission spectra for varied ring configurations by using a two-dimensional finite element model in a square lattice dielectric-rod photonic-crystal structure and achieve both backward-and forward-dropping by controlling the size of the ring resonators and the refractive index of the dielectric-rod in the ring resonators.On the other hand,by changing the arrangement of the column boundary scattering medium and the size of column radius of the ring cavity boundary medium,we can reduce the scattering loss between the waveguide and the ring cavity so as to achieve the optimum filtering effect.关键词：photonic crystal;ring resonator filter;finite element method;transmission power outflow
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发布时间： - 摘要：A Microwave Photonic Filter（MPF）with a pair of Fiber Bragg Grating（FBG）assisted by a ring resonator is proposed on the basis of the in-depth study of the MPF theory.An MPF with the maximum flat filtering response is obtained by optimizing its structural parameters and the system transfer function of such a MPF is acquired on the basis of the detailed analysis by using a signal flow graph.The effects of the coupling coefficient,the reflectivity of the pair of FBG,the length and the gain of the fiber ring on the system transmission characteristics are analyzed by using the MATLAB software.The results show that this filter with such a structure is effective and feasible and has potential applications in microwave and millimeter-wave fiber-optic systems.关键词：MPF;ring resonator;FBG;filtering response
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发布时间： - 摘要：This paper investigates the spontaneous and piezoelectric polarization effects of InGaN/GaN Multiple Quantum Well（MQW）LED with a sapphire substrate.In order to analyze its output characteristics,it imitates InGaN/GaN MQW blue LED chips in the traditional horizontal structure by using MATLAB software.The study shows that the same proportional increase on various interfacial polarization charges of LED can weekly improve its electrical characteristics,but significantly reduces its light output power and internal quantum efficiency chiefly because interfacial charges change the energy band structure,hinders the diffusion and drift of the holes and reduces the radiative recombination coefficient.Changing the dislocation density can reduce the impact of the polarization charge on the LED and improve its performances.关键词：polarization charge;LED performance;energy band structure;electron and hole concentrations
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发布时间： - 摘要：High-rate,large data capacity transmission and processing are key issues in future optical fiber communications.10Gbit/s 850nm Vertical-Cavity Surface-Emitting Laser（VCSEL）-Transmission Optical Subassembly（TOSA）is a key highrate short-wavelength subassembly used in Ethernet and large data processing centers.This paper introduces the structure,chip characteristics,technical indexes and relevant standards for the practical subassembly,reports the high temperature accelerated life test conditions for and results of its chips,discusses the effects of variations in structure,technology and environmental temperature on its performances and points out its applications in the short-range Ethernet and large data processing centers.关键词：large data;850nm VCSEL-TOSA;practicality;reliability;high temperature accelerated life test
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发布时间： - 摘要：In this paper,the Back Propagation（BP）neural network is applied for the purpose of compensating the temperature drift of the pressure sensor and the Davidon Fletcher Powell（DFP）method is adopted to overcome the drawbacks of this network learning algorithm.Algorithm unavailability is effectively solved by search in the descent direction of the L-M learning algorithm and the overflow problem is solved by multiplying a magnification factor added by a disturbance term and thus magnifying the weight updated vector and the weight derivative updated vector.The simulation results show that this method can effectively suppress the effects of temperature on the pressure sensor output and improve the stability and accuracy of the sensor.关键词：BP neural network;DFP method;pressure sensor;temperature compensation
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发布时间： - 摘要：In order to achieve timing synchronization in cell search,this paper studies the Primary Synchronization Signals（PSS）and the Secondary Synchronization Signals（SSS）in Time Division Long Term Evolution（TD-LTE）systems and makes an analysis with the relevant simulation software.On the basis of the TD-LTE wireless integrated test system,it proposes a Digital Signal Processors（DSP）-based scheme that implements timing synchronization by using the characteristics of the synchronization signals,and introduces the implementation process,including timing synchronization,cell ID detection and cell ID number.This scheme has been applied to the development of TD-LTE radio frequency conformance test systems.关键词：synchronization signal;cell search;timing synchronization;DSP
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发布时间： - 摘要：In this paper,rate matching is first implemented for the tailbiting convolutional codes of the Time Division-duplexLong Term Evolution（TD-LTE）systems.After in-depth research on the tailbiting convolutional code rate matching algorithm in the 3GPP protocol and the TD-LTE wireless integrated test system,a fast implementation scheme realized by using a DSP chip is proposed.The results of the decoding program running in CCS3.3verify the feasibility and effectiveness of the scheme and its optimization strategies.关键词：LTE;tailbiting convolutional code rate matching;DSP realization
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发布时间： - 摘要：UE-specific reference signals are used for the demodulation of Physical Downlink Shared Channel（PDSCH）measurements in Long Term Evolution Advance（LTE-A）systems.This paper first investigates the various formulas for the generation of the UE-specific reference signals.Then it designs the flow of program realization and generates the UE-specific reference signals by software programming using TI（Texas Instruments）corporationTMS320C6455DSP.Finally,it gives the specific implementing flow chart for this scheme and the execution efficiency.The verification results show that this scheme satisfies the performance requirements of LTE-A systems.关键词：LTE-A;UE-specific reference signal;DSP realization
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发布时间： - 摘要：In order to keep the user access efficiency from being affected by server timeout in WLAN systems,this paper studies the PORTAL certification,PPPoE certification,EAP certification mode and RADIUS certification process.On the basis of testing and analyzing the user access efficiencies in various authentication modes,it optimizes the RADIUS client authentication process,eliminates the occurrence of user connection failures caused by the misjudgment of server status,avoids long time waiting by users and improves user access authentication efficiency.关键词：WLAN;RADIUS;authentication;efficiency
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发布时间： - 摘要：<正>科技论文的引言是简要说明研究的主要目的、范围,即为什么写这篇论文以及要解决什么问题;前人在本课题相关领域内所做的工作和尚存的知识空白,作简要的历史回顾和现在国内外情况的横向比较;研究的理论基础、技术路线、实验方法和手段,以及选择特定意见方法的理由;预期研究结果及意义。
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