最新刊期
卷 ， 期 4 ， 2014
- 摘要：As Tbit/s high-rate optical transmission has become a technological hotspot in the field of fiber-optic communication,this paper analyzes its key technology,intra-channel multiplexing.On the basis of comparing three technologies,i.e.NyquistWDM,OFDM and Super-Nyquist in terms of spectral efficiency,performance and feasibility,it gives the specific selection and presents an instructive technological solution to the commercial applications of Tbit/s high-rate optical transmissions.关键词：intra-channel multiplexing;optical transmission;sub-channel;spectral efficiency
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发布时间： - 摘要：Owing to the need for performing linear operation,the traditional network coding/decoding algorithms are only suitable to be applied in the electric domain,while thanks to the development of the current all-optical devices,it is possible to realize logic calculus and shift operations.In order to introduce network coding into all-optical multicast networks,this paper studies the algorithms for generating network coding multicast trees and the methods for selecting the coding vector appropriate for optical network coding and simulates and analyzes the presented algorithm.The results indicate that the application of network coding to all-optical multicast can significantly improve the multicast performances.关键词：network coding;coding vector;multicast tree;all-optical multicast
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发布时间： - 摘要：Physical layer impairments in optical networks can cause significant degradation of signal quality.In order to ensure QoS,it is necessary to consider these impairments and the resulted variations in the Routing and Wavelength Assignment（RWA）algorithm.This paper proposes an impairment-aware differentiated RWA algorithm and conducts numerical simulations of regular Mesh networks and Cernet networks.The results show that in the case of satisfying QoS demands,giving priority to ensuring the wavelength assignment for the high-class services in the networks reduces their blocking probability and improves the overall network resource utilization rate.关键词：optical network;impairment-aware;class-based traffic;RWA;QoS
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发布时间： - 摘要：In Path Computation Element（PCE）-based multi-domain intelligent optical networks,lightpath provisioning is a new challenge to the effective resource interaction among various domains and there still exist latency arising from the traditional serial processing in the establishment of the lightpath.In order to better cope with this challenge and solve the problem of latency,this paper proposes a PCE-based Multi-Domain Parallel Signaling（MDPS）mechanism and a Signaling Control Element（SCE）so as to realize rapid cross-domain lightpath provisioning.This mechanism fully utilizes the Hierachical PCE（H-PCE）technology and adopts the client-server architecture of one main PCE/multiple sub-PCEs and each sub-SCE is equipped with a SCE.On the basis of the interaction between PCE and SCE,every domain independently and parallelly carries out the inter-domain signaling process to implement the fast establishment of cross-domain lightpath connection.Simulation results indicate that the proposed mechanism can effectively solve the above-mentioned problem and improve the lightpath provisioning efficiency.关键词：signaling;multi-domain optical network;lightpath provision;PCE
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发布时间： - 摘要：Optical packet encryption is the foundation for improving the security of Automatically Switched Optical Networks（ASON）.On the basis of analyzing the optical packet encryption mechanism and the status of the relevant researches and according to the layered architecture of ASON and the characteristics of BB84 quantum key distribution protocol,this paper presents an improved four-layer architecture-based ASON quantum switch model.Using this model,it proposes a secret sharing encryption-based multi-path quantum key distribution scheme,which is used for long-distance transmission of quantum key.Simulation experiment results verify the feasibility of this scheme.关键词：ASON;optical packet encryption;quantum cryptography;key distribution
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发布时间： - 摘要：In Optical Transport Networks（OTN）,the main function of the Optical Channel Data Unit（ODUk,k=0,1,2）segmentation module is to cut ODUkinto a standard sized packets（±1byte）in a fixed format.As ODU2 is 8-byte data,the number of the remaining data bytes is different after each insertion into the packet.This paper studies the implementation method and circuit design for the remaining data processing in the above process and completes functional simulation and logic synthesis.The results show that this method reduces the resource occupation ratio and increases the circuit operating frequency to 360 MHz.关键词：OTN;ODU;data sequence adjustment;number of remaining bytes
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发布时间： - 摘要：The introduction of a hose model to the Optical Virtual Private Network（OVPN）brings about a topic of optimization,i.e.minimizing the total bandwidth reserved for its users on the premise of ensuring the QoS.On the basis of the traditional Hierarchical Iterative Spanning Tree（HIST）algorithm,this paper proposes an approximate solution algorithm,named Bandwidth Constraint Spanning Tree（BCST）,which traverses all the spanning trees of the entire network physical topology by using the iterative method,and by adopting apruning scheme,finds the spanning trees with relatively smaller cost and time delay.Finally,it verifies the feasibility of the BCST algorithm by practical case simulation and comparison.关键词：OVPN;hose model;bandwidth configuration;optimal spanning tree
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发布时间： - 摘要：For 100Gbit/s（or above）Polarization Multiplexed-Quadrature Phase Shift Keying（PM-QPSK）optical coherent transmission systems,we propose an improved statistical moment-based intraband Optical-Signal-Noise-Ratio（OSNR）monitoring method and carry out its numerical simulation in such an established system.The results show that when this method is used,all the monitoring errors of RZ code modulated signals with different duty cycles are smaller than 0.5dB in the OSNR range of 525dB and in line with the requirement of the commercially available coherent receivers for the OSNR at the receiver end,taking the reference value of 14 dB,the system Chromatic Dispersion（CD）tolerance is 2 400ps/nm and that for the 1storder Polarization Mode Dispersion（PMD）,i.e.Differential Group Delay（DGD）,is 62ps/nm in the monitoring range of0.5dB.关键词：fiber-optic communication system;OSNR monitoring;PM-QPSK;CD;PMD
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发布时间： - 摘要：This paper presents a scheme for the simultaneous generation of 2-and 3-order Ultra-Wide Band（UWB）signals on the basis of the Self-Gain Saturation（SGS）and Cross-Gain Modulation（XGM）effects of Semiconductor Optical Amplifiers（SOA）and analyzes its operating principle.It simulates this scheme by using Optisystem 9.0and obtains 2-order UWB signals with the central frequency of 6GHz and relative bandwidth of 143% and 3-order UWB signals with the central frequency of8 GHz and relative bandwidth of 120%,both in compliance with the FCC requirements on UWB signals.Furthermore,it analyzes the impacts of the input pulse signal width,detecting light and pump optical power on the generated signals.关键词：UWB signal;SOA;SGS;XGM
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发布时间： - 摘要：QoS routing problem in Ad hoc networks including such constraints as delay,delay jitter,bandwidth and packet loss is an NP-complete problem.It is difficult for the traditional plane QoS ant routing algorithm to solve the contradiction between improving the global search ability of the algorithm and speeding up the convergence rate.In relation to the above problem,this paper presents a Hierarchical QoS Ant Colony（HQAC）algorithm.On the basis of the hierarchical structure,it improves the routing search process of the algorithm and optimizes the pheromone update formula.Simulation results show that compared with the traditional QoS routing algorithms,this algorithm is remarkably improved in searching the global optimal solution,especially in convergence rate and other performances.关键词：Ad hoc network;ant colony algorithm;HQAC algorithm;pheromone
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发布时间： - 摘要：This paper introduces a Frequency Domain Reflectometry（FDR）-based method and apparatus design for feed cable Voltage Standing Wave Ratio（VSWR）fault location.By sending frequency sweeping test signals at specific bands,it transfers the power signal value overlaid by the sending power value,the faulty feed cable reflected signal and the incident signal vector through the communication interface to the computer and its software calculates the distance of the feed cable fault points on the basis of these two power values,thus achieving the accurate location of the feed cable fault.关键词：FDR;feed cable VSWR;fault location;apparatus
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发布时间： - 摘要：With the rapid development of visible light communication technology and other emerging optical communication technologies and the increasing demand for optical terminal multi-user access networking communications,the study on the multiple access technologies in the optical field gradually highlights their significance.At present,the major multiple access technologies in the optical field include Optical Wavelength Division Multiple Access（OWDMA）technology,Optical Code Division Multiple Access（OCDMA）technology,Optical Time Division Multiple Address（OTDMA）technology,Sub-Carrier Multiple Access（SCMA）technology and the corresponding hybrid multiple access technologies.This paper introduces their basic principles,main characteristics and applications and on the basis of analyzing and comparing their performances provides the theoretical basis of their selection for the optical terminal multi-user access communication systems.In addition,it predicts the trend of their future development.关键词：OWDMA;OCDMA;OTDMA;SCMA
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发布时间： - 摘要：Laid in the complex ocean environment,the Submarine Optical Fiber Cable（SOFC）is vulnerable to external damaging factors,especially the anchor damage.In view of the limitations of the existing monitoring technologies,this paper proposes to apply the dual M-Z interferometer-based distributive fiber vibration sensing technology to the on-line monitoring of the SOFC and establishes a mathematical model for the system sensing and positioning by theoretical derivation.Furthermore,by combining with the SOFC routing radar surveillance system,it effectively solves the possible problem of false-alarm in practical monitory systems and improves the system reliability.关键词：SOFC;anchor damage;optical fiber sensing
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发布时间： - 摘要：Slow-light technology is a key technology for realizing optical buffers in all-optical networks.In order to realize slow light with low group velocity and large bandwidth,this paper designs a novel waveguide structure,which is based on two-dimensional square lattices with the dielectric cylinder rotated by-45°so as to produce line defects,achieves slow light transmission and applies it to the optical buffer technology.In addition,it optimizes the slow light performances of the structure further by changing the radius of the dielectric cylinder and the width of the waveguide,conducts calculation and simulation by using the supercell-based plane wave expansion method,obtaining the dispersion curve of the defected mode.Furthermore,it analyzes in detail the properties of transmission group velocity and group velocity dispersion of light in waveguide and achieves the maximum group speed of only 0.007 89 c（cis the speed of light in vacuum）,and the group velocity dispersion in the range-106106 ps2/km.When a designed 1mm-long photonic crystal structure is applied to the optical buffer,it can achieve the maximum cache time of 2.778 ps and the maximum cache capacity of 145.98 bit.关键词：photonic crystal;slow light;optical buffer
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发布时间： - 摘要：In order to select a rational Fiber Bragg Grating（FBG）vibration demodulation scheme in accordance with the vibration detection requirements and enhance the performance of FBG vibration sensing demodulation systems,this paper dissects in depth various factors affecting the system demodulation performances,compares the system sensitivity and demodulation range of matching FBG method,edge filter method and laser matching method by using MATLAB software and analyses the variation trends of the sensitivity and demodulation range of these three methods when 3dB bandwidth of FBG is changed.The results have some value of reference for rationally building an FBG vibration sensing demodulation system.关键词：FBG;vibration demodulation sensing system;sensitivity;demodulation range
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发布时间： - 摘要：Two parameters for evaluating the performances of 100Gbit/s line transponder are introduced in this paper:receiver Optical Signal Noise Ratio（OSNR）tolerance and pre-FEC OSNR corresponding to the maximum module BER.The former is used to evaluate the overall performance of the hardware and software algorithms of the optical module,while the latter is used to evaluate the performances of the optical module after the software algorithm is closed.Furthermore,the test block is given,tests are performed by using the integral method and the test results are to be calibrated.This test method has certain value of reference for the OSNR tests on other line optical modules.关键词：100Gbit/s;transponder;OSNR;pre-FEC;BER
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发布时间： - 摘要：Lasers are widely applied in such areas as ranging and sensing for good monochromaticity and energy concentration and linewidth is an important index for measuring laser monochromaticity.Therefore,it is of great significance to investigate the methods for measuring narrow linewidth.This paper systematically introduces several heterodyne-based methods for linewidth measurement and conducts the relevant experiments and comparative analysis.The results show that Michelson interferometer with Faraday rotator mirror is an ideal method for measuring narrow laser linewidth.关键词：linewidth measurement;M-Z interferometer;Michelson interferometer;fiber ring cavity
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发布时间： - 摘要：This paper proposes a novel photonic crystal-based dual-wavelength THz filter.Consisting of a resonator that is the optimized combination of three point defects in a square lattice photonic crystal and line defects,this resonator can realize dualwavelength THz downloading function.It investigates the transmission characteristics of two beams of optical wave in the filter,using the Finite-Difference Time-Domain（FDTD）method,and simulates the corresponding transmission spectrum and time domain response graph.Simulation results show that this filter can perform single-channel dual-wavelength filtering functions and has such advantages as large quality factor Qvalue of a resonator,narrow filtering bandwidth,small loss,fast steady response time,small volume and easy system integration.关键词：photonic crystal;THz wave;combination resonator;filter;FDTD method
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发布时间： - 摘要：This paper introduces the performances of an ultrastable tunable narrow-band fiber laser and its implementation scheme.Based on the commercially available Er-doped fiber amplifier,fiber Bragg grating and variable optical attenuator,this fiber laser has high output power stability（<0.92% within one hour）,narrow linewidth（<52pm）,high sidemode suppression ratio（30dB）and large tunable range（over 20nm）.The entire system can not only be used as a narrowband fiber laser but also as a wideband amplified spontaneous emission light source and an Er-doped fiber amplifier.Furthermore,this system can be easily realized in an ordinary laboratory.关键词：fiber laser;specific laser system design;laser spectroscopy
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发布时间： - 摘要：Strain and temperature are simultaneously measured by using the conical structure of a single Fiber Bragg Grating（FBG）sensor and the necessary parameters.Information is encoded by writing it in a linearly etched fiber and making it into a conical structure and using the peak wavelength and the waveform half peak width of the sensor.Strain-temperature cross-sensitivity of a single FGB can be resolved by utilizing the feature that its half peak width is only dependent on the applied strain,but not on temperature variations.Matlab simulation results indicate that the errors of the strain and temperature are defined as±15.26μεand±1.92℃respectively.关键词：FBG;fiber-optic sensor;temperature-strain cross sensitivity;simulation
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发布时间： - 摘要：As a new Radio-Frequency（RF）band,W-band（75110GHz）has wider bandwidth and higher frequency in comparison with other bands,enabling itself to provide mobile data communications with gigabit wireless links,which has become a hot topic about the next generation wireless communication systems.There are a variety of W-band technologies for realizing large-capacity W-band communication systems,e.g.high-order modulation,antenna multiplexing and multi-band modulation.These technologies optimize the system in terms of modulation efficiency,band utilization and bandwidth.This paper introduces in depth the system background,research results and technical support,so as to offer a reference for future researches.关键词：W-band;antenna polarization multiplexing;multi-band multiplexing;large-capacity converged fiber-wireless system;RF band
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