最新刊期
卷 ， 期 6 ， 2012
- 摘要：For the purpose of studying the key technologies for future ultra-high-rate large-capacity optical transmission systems,we realize a 16-superchannel WDM transmission of 1.92 Tbit/s/ch Polarization Division Multiplexed（PDM） 16QAM Orthogonal Frequency Division Multiplexing（OFDM）over 80 km SMMF,the total data rate of which is 30.7 Tbit/s in C band occupancy.Each superchannel consists of 45 subchannels with a spectral width of 250 GHz and a spectral efficiency of 7.68 Gbit/s/Hz.The BER of all channels after 80 km transmission is smaller than 2×10-2,the third generation FEC decoding limit.关键词：OFDM;coherent optical receiver;spectral efficiency
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发布时间： - 摘要：This article describes in detail the design and implementation of a 240 Gbit/s Orthogonal Frequency Division Multiplexing（OFDM） real-time optical communication system.It first generates 3×15 orthogonal optical subcarriers by using a multi-carrier generating device,and modulates each subcarrier with OFDM signals at 4 Gbaud/s using a 4QAM signal format.Then it demodulates the optical OFDM signals in every channel at the receiver end using the corresponding intrinsic subcarrier and implements real-time processing of the sampled signals using FPGA.The total effective data rate reaches 240 Gbit/s,the highest among the reported real-time OFDM transmissions.关键词：OFDM;real time;ADC;FPGA
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发布时间： - 摘要：This paper first reviews the industrial background of realizing ultra-wideband transmission and introduces two main approaches for its realization: OFDM modulation and Nyquist filtering and their fundamental principles.It then analyzes and compares their advantages and disadvantages.Finally,it summarizes the present conditions of their researches and looks forward to their prospects.关键词：OFDM modulation;Nyquist filtering;ultra-wideband
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IQ imbalance compensation and phase noise estimation for coherent optical OFDM communication systems
摘要：In this paper,the linear impairments of Coherent Optical Orthogonal Frequency-Division-Multiplexed（CO-OFDM） communication systems,including IQ imbalance and linear phase noise,are studied and a decision-aided compensation method without the need of periodic pilots proposed.Simulation results show that the proposed technique can effectively estimate and compensate these two linear losses.On this basis,a novel scheme is presented for joint compensation of IQ imbalance and phase noise in the presence of channel distortion.关键词：OFDM;IQ imbalance;phase noise;decision-aided- 2
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Reception of dual-LP11-mode CO-OFDM signals through few-mode compatible optical add/drop Multiplexer
摘要：We report successful reception of dual-LP11-mode CO-OFDM signals traversing few-mode compatible Optical Add/Drop Multiplexer（OADM）.The OADM utilizes thin film filters and a double-reflection mechanism to perform add/drop functions of mode-division multiplexed signals.The power penalties for add,drop and through ports are 2.6,2.4 and 0.7 dB respectively for 3×318 Gbit/s OFDM signals.关键词：few-mode fiber;OADM;fiber-optic communication;coherent communication- 3
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发布时间： - 摘要：The All-Optical Orthogonal Frequency-Division Multiplexing（AO-OFDM） technology is used to implement multicarriers and Optical Inverse Discrete Fourier Transform（OIDFT）/Optical Discrete Fourier Transform（ODFT） by way of optical processing,which has the advantages of improving the processing rate and reducing power consumption.By using the AO-OFDM technology in combination with the single-channel 100 Gbit/s DP-QPSK high-order modulation technology,we can realize a 400 Gbit/s transmission system with a spectral efficiency of 2.7 bit/s/Hz and when the chromatic dispersion is completely compensated,we achieve a transmission with the maximum Spectral Efficiency-Distance Product（SEDP） of 3 564 km·bit/s/Hz.With 12.5% Optical Cyclic Prefixes（OCPs） inserted,the system dispersion tolerance reaches 70 ps/nm.The experimental results show that using the AO-OFDM technology,the system has better performances and can be used as a practical application scheme for next generation 400 Gbit/s transmission systems.关键词：AO-OFDM;DP-QPSK;high-rate transmission system
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发布时间： - 摘要：On the basis of the analysis of the theoretical model of Fourier transform-based all-optical OFDM,we construct a multiplexing/demultiplexing module by Mach-Zehnder interferometer cascading and directly carry out an IDFT/DFT process in the optical domain.Furthermore,with the modulation of DPSK,DQPSK,4QAM and 16QAM,we simulate 8×40 Gbit/s OFDM system transmission without GI by using the all-optical multiplexing/demultiplexing module and analyze its performances such as BER.关键词：OFDM;Fourier transmission;all-optical multiplexing;optical modulation
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发布时间： - 摘要：We propose a novel scheme of optical buffer with a fairly large Bandwidth-Delay Product（BDP）,which is based on a single micro-ring resonator and an OFDM transmitter.The large BDP is gained by distributing data over the subcarriers of the OFDM system via the resonator.We build a numerical model for the entire system and achieve a large BDP with only five subcarriers considered in the simulation.关键词：photonic integration;micro-ring resonator;slow-light
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发布时间： - 摘要：In this paper,several pilot-aided channel estimation methods are compared and analyzed for Orthogonal Frequency Division Multiplexing（OFDM） systems in atmospheric laser communications.The simulation results show that while improving the channel estimation accuracy,the Singular Value Decomposition-Linear Minimum Mean Square Error（SVD-LMMSE） algorithm reduces the complexity of the system computations and the increase of the Cyclic Prefix（CP） effectively improves the system performances.关键词：atmospheric laser communication;channel estimation;OFDM
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发布时间： - 摘要：The Orthogonal Frequency-Division Multiplexing Passive Optical Network（OFDM-PON） technology is one of the current research focuses in optical access networks.This paper first briefly describes its study background,explains its principle,network architecture and key technologies.Then it studies and analyzes OFDM-PON-based services and bandwidth scheduling and predicts the prospects of its applications.Study results show that compared with the conventional PON systems,OFDM-PON system has its transmission bandwidth dramatically increased and realizes subcarrier-,modulation format-,and time slot-based services and bandwidth scheduling.
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发布时间： - 摘要：In order to increase the transmission distance of 100 Gbits/s optical communication systems,this paper constructs a high-gain Non-Binary Quasi-Cyclic Low-Density Parity Check（NB-QC-LDPC） code over the Galois Field GF（4）,which is suitable for 100 Gbit/s optical communication systems using QPSK or DQPSK modulation formats.Using the Logarithm Fourier Sum-Product Algorithm（Log-Fourier SPA）,it analyzes the BER performance of NB-QC-LDPC.The results show that compared with the binary QC-LDPC code,the NB-QC-LDPC code with a code length 500 and code rate 0.8 can provide approximately 1 dB coding gain at the BER of 10-8 and when the code rate decreases from 0.9 to 0.8 at the same BER,this code can provide additional code gain of about 0.6 dB,which means that the NB-QC-LDPC code outperforms the binary QC-LDPC code at the lower code rates.关键词：optical communication system;NB-QC-LDPC;Log-Fourier SPA;QC-LDPC
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发布时间： - 摘要：This paper first summarizes a general optical communication model for underwater nodes and takes node survival rate as the reliability index of cabled seabed observatory networks.In view of reduced reliability and increased difficulty in cable installation arising from multiple underwater branching nodes,it optimizes NEPTUNE into a crossed ring topology that contains only two multi-branching nodes.The reliability simulation results of the above two kinds of networks reveal that the crossed ring topology is similar to NEPTUNE in reliablity,but more favorable for power supply and network installation because of less number of branching nodes.关键词：seabed observatory networks;reliability;directed graph;Monte Carlo simulation
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发布时间： - 摘要：In this letter,a new manufacturing process for high-performance Polarization Maintaining Fiber（PMF） is developed and the PMF with 80 μm cladding diameter fabricated.The experimental results show that this fiber has fine polarization cross-talk performance in the temperature range from-50 to 85 ℃,with the typical cross-talk change value of 3.232 dB,and good bending resistance and abrasive fiber ends.关键词：PMF;fiber-optic gyroscope;specialty fiber;fabrication;application
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发布时间： - 摘要：Analysis is made of the characteristics of a special optical fiber widely used in Light Triggered Thyristors（LTT） and systematical study of such crucial optical characteristics as the dopants of the fiber core and cladding and the cladding-core diameter ratio,providing some reference for choosing specialty optical fibers with preferable cost performance for LTTs.The results indicate that optical fibers with core diameter of 200 μm and cladding diameter of 250 μm designed in step index profile,Ge-F codoped in the core with Ge concentration of 16 mol% and F of 5 mol%,and cladding doped with F with concentration of 1 mol% have better triggering performance and fit for LTT applications.关键词：large core multimode fiber;core doping;ultrahigh voltage;LTT
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发布时间： - 摘要：In order to facilitate the precise control of the shape of fused taper fibers,their forming models in the fused biconical taper process are first established on the basis of theoretical and experimental studies and the basic principle for the fused taper formation analyzed.Then a theoretical analysis is made of the taper shapes in respect of the constant and linear changes in the heating zone and the relations of the heating zone length and taper distance to the fused taper transition zone shapes,the taper waist length and radius defined respectively.Finally the theoretical shapes and the experimentally resulted ones of a series of fused taper fibers are presented.The experimental results show that the actual measured values are very close to the theoretical ones with a relative error of <3.89%.关键词：fused taper fiber;fused biconical taper;fused taper shape
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发布时间： - 摘要：The effective coverage of supervised zones and maximized extension of network life cycles are key topics in the research on wireless sensor networks.For this purpose,this paper presents a node scheduling strategy-based effective energy coverage algorithm.On the one hand,this algorithm effectively covers the chosen targets in accordance with the node probability density formula worked out on the Poisson distribution model.On the other hand,it enables the residual energy of the sensor nodes to be in balance with the node consumption energy through the node state scheduling mechanism updating and the dynamic conversion of the neighboring node matched scheduling so as to extend the network life cycle.The simulation results show that this algorithm can implement the effective coverage of the supervised zones,optimize the network resource allocation and extend the network life cycle.关键词：wireless sensor network;scheduling strategy;life cycle;coverage;power;node
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发布时间： - 摘要：In view of the difficulties in the blind estimation of the Pseudo-random Noise（PN） sequence OVSF code for WCDMA uplink signals in low Signal to Noise Ratio（SNR）,an approach is proposed by using the correlation matrix and cumulative average of the signals combined with its singular value decomposition.When such parameters of the WCDMA signals as the OVSF code period and rate are known,the received signals are periodically divided into multiple continuous observation vectors based on the OVSF sequence period with a random fixed value as the starting point for the correlation matrix and cumulative average.Then the OVSF sequence of the WCDMA signals is blindly estimated from the main component eigenvector and the signals are despreaded.Simulation results show this method works well in a lower SNR scenariors.关键词：WCDMA signals;OVSF sequence;correlation matrix;singular value decomposition;despreading without the code
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发布时间： - 摘要：On the basis of Ad hoc On-Demand Distance Vector Routing（AODV） protocol and in view of the defects of poor routing performance arising from unitary routing criterion for traditional AODV Wireless Mesh Networks（WMN）,this paper designs a novel Improved AQDV（IAODV） by employing a cross-layer design method.Furthermore,it extracts such factors affecting the link quality as the current node load and link delivery rate by the cross-layer operation mechanism in the route calculation process and designs a rational routing decision function in combination with the routing hops.Theoretical analysis and NS2 simulation results prove that this route optimization mechanism improves the throughput,reduces the network delay and achieves load balanced routing.关键词：WMN;routing protocol;cross-layer design;AODV
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发布时间： - 摘要：In view of the difficulties in multi-Access Points（AP） and multi-user terminal access tests in the development of wireless Access Controllers（AC）,this paper presents the design and implementation of an AP simulator.Based on the principle of Controlling and Provisioning of Wireless Access Point（CAPWAP）,this simulator simplifies the implementation process of a real AP and simulates its access control flow.Furthermore,in line with the testing requirements,it can complete multi-AP,multi-user terminal access control and the simple assessment of the AC performances.关键词：AP;wireless AC;simulator;CAPWAP
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发布时间： - 摘要：<正>近日,从国家发展改革委获悉:在国家创新能力建设和国家工程研究中心建设20周年主题活动中,武汉邮电科学研究院科技创新成果转化能力和创新能力建设项目的组织与运行管理水平再次得到国家发改委认可并获得国家发改委多项表彰。武汉邮电科学研究院光纤通信技术国家工程研究中心荣获国家工程研究中
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