最新刊期
卷 ， 期 5 ， 2011
- 摘要：Dynamic Routing and Wavelength Assignment（RWA） is a key issue in intelligent optical networks.This paper presents an improved ant colony algorithm to tackle this issue,in which link idleness probability is added to the ant transition probability as a constraint and simultaneously random disturbances are introduced to prevent premature convergence of searches into the optimal local path.Simulation results show that compared with the conventional Dijkstra+FF algorithm,the modified algorithm significantly decreases the blocking probability and increases the resources utilization rate.关键词：intelligent optical network;RWA;ant colony algorithm;blocking probability
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发布时间： - 摘要：This paper proposes two new methods for the generation of UWB doublet signals using the Cross-Gain Modulation（XGM） effect of Semiconductor Optical Amplifiers（SOA） and the Fiber Bragg Grating（FBG） optics.It analyzes their working principles and performs simulation experiments on two systems,obtaining UWB doublet signals that conform to the FCC standard,one with a center frequency of 5.35 GHz and a relative bandwidth of 114% and the other with a center frequency of 4.7 GHz and a relative bandwidth of 132% respectively.The simulation results verify the feasibility of the proposed methods.Finally,it analyzes the existing problems of these two methods.关键词：UWB signal;SOA;XGM;FBG
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发布时间： - 摘要：On the basis of the system architecture and implementation process of the Web Network Management（NM） system of the Web Server,this paper first studies the configuration mechanism and implementation of the static routing with Wind Web Server as the platform.Then,it describes the components of the embedded NM system and analyzes and realizes the front-end and back-ground processing modules.Finally,it conducts comparison tests on the functions of the static routing.The results show that this Web-based NM mode is stable and reliable as it can synchronize with other NM modes in functions and satisfies various configuration requirements.关键词：static routing;embedded NM;SSI
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发布时间： - 摘要：As the conventional switch chip decodes the Virtual Local Area Network（VLAN） packet in fixed hardware,so that it is not possible to alter the processing flow,this paper presents a network processor-based programmable pipeline scheme.It studies the processing mechanism of the pipeline,analyzes the principle of VLAN mapping and describes in detail the implementation of the VLAN module.Test results indicate that this software operates stably and is significant to the development of the QinQ software.关键词：pipeline;micro-coded;network processor;module
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发布时间： - 摘要：Protection of the existing investment for Multi-Service Transport Platform（MSTP） equipment and smooth evolution from MSTP networks to Packet Transport Networks（PTN） platform are common concerns for telecom operators.In connection with this issue,this paper investigates the packetization of the existing MSTP equipment to upgrade it to an enhanced MSTP（MSTP+） with dual-plane functions of TDM and PTN,and analyzes the system architecture of dual-core MSTP+ and the scheme for its networking with PTN equipment.The conclusion is that the hybrid networking of dual-core MSTP+ backward compatible with PTN is the optimal solution to the protection of the existing network investment.关键词：MSTP+;PTN;networking
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发布时间： - 摘要：The automation communication technology is a key technology for distribution automation,which determines its level of intelligence.The commonly used technologies include optical fiber communication,middle-and low-voltage carrier,GPRS and 3G wireless.On the basis of the application analysis of EPON technology in intelligent distribution networks and in connection with the experiments in the intelligent distribution networks of Guangdong power grid,this paper verifies the feasibility and significance in popularization of the EPON technology in intelligent distribution networks.关键词：intelligent;distribution network;EPON;popularization
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发布时间： - 摘要：On the basis of the nonlinear Schrdinger equation describing pulse propagation in photonic crystal fibers,we numerically investigate the effects of self-steepening on red-shift dispersive waves when the third-order dispersion of the fiber is negative.The results show that due to the generation mechanism of the red-shift dispersive waves is different from that of blue-shift dispersive waves,the effects on the former is not significant.关键词：self-steepening;dispersive wave;photonic crystal fiber
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发布时间： - 摘要：Submarine cable faults are located mainly by using the electric field method and the magnetic field method.On the basis of the transmission theory,the formula for signal attenuation in the submarine cable conductors are deduced when the two methods are used and the signal attenuation features analyzed.Numerical simulation results show that when the fault point is 1 000 km away from the shore end,the attenuation in certain type of cable is over 95% when the magnetic field method is used,but when the electric field method is used,it is less than 8%.That means that in respect of attenuation resistance,the latter is much superior to the former.关键词：submarine cable;fault location;the electric field method;the magnetic field method;signal attenuation
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发布时间： - 摘要：A compact 4×4 Multimode Interference（MMI） combiner with the size of 3 890 μm×100 μm is designed by making use of the advantage of the InP-based air-restricted waveguide in small bending radius.A tapered waveguide is inserted between the input/output waveguides and the MMI zones,effectively improving the performance of the combiner.The device is simulated by the three-dimensional wide-angle beam propagation method,obtaining the optimized parameter values and thus optimizing its structure.关键词：InP-based waveguide;MMI;beam propagation method
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发布时间： - 摘要：In this paper,we reduce the Polarization-Dependent-Frequency Shift（PDFS） of the DQPSK demodulator with a 91 μm-thick quartz half-wave plate.Using the optimized tapered waveguide structure at the wave-plate,we reduce the additional loss brought about by the inserted half-wave plate to 0.41 dB and simulate the demodulator in the C-band.The results show that demodulators with such a structure have low insertion loss and high extinction ratio.关键词：DQPSK;insertion loss;beam propagation method
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发布时间： - 摘要：This paper studies the spectral beam combining technology for multiple Main Oscillation Power Amplifier（MOPA） pulse lasers by using the array fiber grating spectral beam combining technology.Then it simulates the output process of the multiple MOPA pulse laser by using this technology and studies the distortion of the time domain pulse shape after beam combining and presents the method for improving the output pulse flattening.The study results indicate that the output pulses become more flattened by controlling the synchronization of the input MOPA pulse laser in each channel with an interval of 2 ns.关键词：fiber-optic laser;spectral beam combining;Array Fiber Grating（AFG）;MOPA
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发布时间： - 摘要：On the basis of the all-optical regeneration technology for Self-Phase-Modulation（SPM） effect and offset filtering in highly nonlinear fibers,we analyze the effects of the input signal power and filter wavelength offsets of the cascaded regenerator on the input signal amplitude jittering and Q values when the input pulse width,fiber parameters and filter bandwidth are constant.Numerical simulation results indicate that the optimized input signal power and filter offsets suppress both the cascaded signal amplitude jittering and spurious pulses and the second-stage regenerated Q value is improved by as much as of 2 dB than the first-stage regeneration.关键词：highly nonlinear fiber;SPM;cascaded all-optical regenerator;offset filtering
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发布时间： - 摘要：In order to find a dielectric-loaded inverted trapezoid ridge waveguide with the optimum cutoff characteristics,a dielectric-loaded inverted trapezoid symmetrical dual-ridge waveguide is presented.Its cutoff characteristics in the TE mode,i.e.the cutoff wavelength of the main module and single-mode bandwidth,are calculated with the help of MATLAB by using the finite element method.The dominant mode field pattern is drawn,the relationship between the cutoff characteristics and the relative dielectric constant analyzed and the relationship curve plotted.These results provide certain theoretical basis and the reference data for the design and engineering applications of dielectric-loaded waveguides.关键词：cutoff characteristics;dielectric-loaded waveguide;finite element method;ridge waveguide;single-mode bandwidth
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发布时间： - 摘要：In this paper,using Finite Difference Time Domain（FDTD） method,we numerically obtain the broadband frequency response characteristics of a new type of the Photonic Crystal Ring Resonator（PCRR） and analyze the impact of changing the dielectric constant on the transmission characteristics of PCRR.On this basis,we establish a three-wavelength photonic crystal divider,and in connection with the analysis of the dynamic distribution of light intensity in this model,achieve the frequency division at 1 500,1 550 and 1 610 nm.Numerical results show that compared with the transmission characteristics of micro-cavity,PCRR can simultaneously "download" multiple narrowband signals in the multi-wavelength divider,while compared with waveguide coupling,the design of its structural parameters design is more flexible.关键词：FDTD method;ring resonator;transmission spectrum;three-wavelength divider
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发布时间： - 摘要：In view of the disadvantages of the threshold decision method in high false alarm rate and difficulty in distinguishing eavesdropping and intrusion from other artificial disturbances,this paper presents a feasible eavesdropping detection method on the basis of analyzing the eigenvector of interfering signals under different disturbances extracted by means of wavelet packet energy analysis.This method can effectively detect and distinguish eavesdropping from other artificial disturbances occurring in optical cable lines.关键词：interferometric fiber-optic sensor;wavelet packet analysis;eavesdropping detection
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发布时间： - 摘要：On the basis of chirped fiber gratings and long-period gratings,a novel signal demodulation method for polymer micro-ring sensors and micro-ring sensor arrays is presented.Linear edge filtering is realized by adjusting the peak wavelength of the long-period gratings to match the range of sensing.In this method,demodulation is achieved with high resolution of 31pm and in dual-channel systems and the wavelength bandwidth of each channel is 2.4 nm.This system is composed of all-fiber devices.关键词：micro-ring sensor system;chirped fiber grating;signal demodulation
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发布时间： - 摘要：Acoustooptic Tunable Filters（AOTF） based on different dielectric materials have different properties and applications.At present,the main dielectric materials applied in AOTF in infrared,visible and ultraviolet bands are a-SiO2,TeO2 and TAS.In order to develop better AOTF,researchers are seeking for new birefringent crystal materials to replace a-SiO2 and TAS.This paper reviews and discusses the studies in recent years on TeO2-KDP-,MgF2-and Hg2Cl2-based AOTF.The results show that these materials present more advantages,but also show some deficiencies,so it is necessary to select proper materials in different applications.
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发布时间： - 摘要：In order to find a better peak-search algorithm for the center wavelength detection in Fiber Bragg Grating（FBG）,the compilation and debugging of 9 peak-search algorithms for FBG demodulation systems are completed by using the LabVIEW technology and MATLAB and their parameters and advantages and disadvantages are analyzed and compared.On the basis of error analysis of the simulated and measured FBG signals and in connection with the experimental study and algorithm simulation,the algorithm errors and the related influencing factors are given.The results show that the optimal peak-search algorithm is the Gaussian fitting algorithm.关键词：FBG;demodulation system;peak-search algorithm
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发布时间： - 摘要：The 3G data services mainly occur in the building interior and in-depth indoor coverage is a problem demanding prompt solution from the operators.This paper introduces a micro interference cancellation repeater using the digital echo cancellation technology.In an all-in-one design,in which the donor antenna and the service antenna are integrated in one body,removing the need for extra cable and antenna installation and realizing a real plug-and-play capability,it provides an economical and rapid solution to such problems as signal attenuation and blind zones caused by buildings.关键词：indoor wireless coverage;micro repeater;interference cancellation
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发布时间： - 摘要：On the basis of the simplified Maximum Likelihood（ML） estimation algorithm,a novel time and frequency synchronization algorithm for the TD-LTE systems is proposed and realized in the TMS320C64x Digital Signal Processor（DSP）.Simulation results show that this algorithm is characteristic of stability and low computation complexity and can work well in different channel scenarios.关键词：TD-LTE system;time and frequency synchronization;ML algorithm;DSP
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