最新刊期
卷 ， 期 3 ， 2015
- 摘要：The Faster-Than-Nyquist（FTN）signaling-based scheme is a high spectral efficiency transmission scheme for largecapacity optical communication systems.This paper reviews the latest FTN signaling-based transmission schemes in the world,such as cascaded multi-modulus blind equalization FTN,digital FTN and Soft Output FTN（SOFTN）.The cascaded multimodulus blind equalization FTN can effectively suppress noise and inter-channel crosstalk,the digital FTN can effectively simplify the system structure and the SOFTN has the highest spectral efficiency.It analyzes and compares in detail their performances and principles,which can be used as the basis for the design of future long-range large-capacity fiber-optic communication systems.关键词：FTN signaling;spectral efficiency;digital FTN;SOFTN
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发布时间： - 摘要：With highly-efficient digital signal processing capability,the Coherent Optical Orthogonal Frequency Division Multiplexing（CO-OFDM）system is considered as a promising option for future 100Gbit/s high-rate optical transmissions.This paper analyzes the transmission mechanism and mathematical model of the Polarization Division Multiplexing（PDM）-based COOFDM technology and on this basis discusses a joint signal equalization algorithm for this system.Numerical simulation results verify that using this algorithm,the said system can effectively suppress the noise effects brought about by PDM,realizing the insensitive reception of the polarization signals.Specifically,the systemQvalue is lowered by only 0.3dB than the CO-OFDM system after 960 km single-mode fiber transmission without any polarization controller.关键词：coherent optical communications;OFDM;PDM;PMD
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发布时间： - 摘要：In view of the influence of the frequency-selective transmitter In-phase/Quadrature-phase（IQ）imbalance on the transmission performance of Coherent Optical Orthogonal Frequency Division Multiplexing（CO-OFDM）systems,this paper proposes a Decision Feedback（DF）-based IQ imbalance estimation algorithm and compares it with the traditional Pilot Insertion（PI）algorithm.Simulation research and theoretical deduction results indicate that the proposed algorithm can not only effectively estimate IQ imbalance and channel parameters,but also improve the system BER performance.关键词：CO-OFDM;IQ imbalance;DF
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发布时间： - 摘要：For the compensation of the laser phase noise and frequency offset estimation in high-rate coherent optical communication systems,a Multi-Symbol Differential Detection（MSDD）-based phase recovery algorithm is designed and the system performances and MSDD compensation capabilities under the influence of ASE noise,laser linewidth and frequency offset are studied.Simulation results show that this algorithm produces significant compensation effects on the laser linewidth and frequency offset.Specifically,for a 20 GBaud QPSK modulated system with 1MHz linewidth and 100 MHz frequency offset,the OSNR penalty is only 0.6dB when its BER is 10-3.关键词：coherent optical communication;laser phase noise;phase recovery;MSDD
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发布时间： - 摘要：We present a novel Manipulated Rotating Binary-Phase-Shift Keying（MR-BPSK）technique in this paper.On the basis of a pre-defined binary sequence,we randomly rotate the BPSK signals by 0°or 90°and the resulted fake QPSK signals can be recovered by using the traditional Constant Modulus Algorithm（CMA）.Using the proposed method,we successfully implement 440 km 2Gbit/s repeaterless transmission.关键词：coherent detection;repeaterless transmission;BPSK
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发布时间： - 摘要：For some key technological issues in high-rate Optical Time Division Multiplexing（OTDM）systems,such as clock extraction,time division demultiplexing and dispersion compensation,we present an 8×40Gbit/s OTDM system technological scheme.The results indicate that by choosing appropriate clock extraction and the symmetrical dispersion shifted fiber-based dispersion compensation technology,we can demultiplex the 40Gbit/s RZ signals in every channel in one timeslot,and with good quality at that.This system realizes 320Gbit/s OTDM communication.关键词：OTDM;dispersion compensation;clock extraction
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发布时间： - 摘要：In order to study large-capacity ultra-long span repeaterless optical transmission technologies,we realize for the first time a 286 km ultra-long span repeaterless transmission in a 40×10Gbit/s Optical Transport Network（OTN）system by using an ultra-low loss optical fiber as the transmission medium,the Enhanced Forward Error Correction（EFEC）technology,hybrid optical amplifiers and pre-bypass Remote Optically Pumped Amplifiers（ROPA）.This system continuously runs for 24 hwithout any code error,providing a basis for measuring the performance indexes and application standard of the ultra-long span large-capacity fiber-optic transmission ROPA system.关键词：ultra-long span repeaterless optical transmission;EFEC;ROPA
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发布时间： - 摘要：This paper proposes an improved shared protection strategy for Traffic Grooming（TG）-supporting Elastic Optical Networks（EON）,which provide classified shared protection for paths with different levels of granularity,e.g.optical tunnel and low-rate subcarrier,so as to ensure protections for tunnel-level paths.Simulation results show that the proposed protection algorithm is significantly improved in terms of service blocking probability and resource utilization rate as compared with the traditional ones:the former is reduced by 0.47 and the latter improved by 10.95% when the protection band G =16frequency slots.关键词：EON;traffic grooming;shared protection;resource utilization rate
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发布时间： - 摘要：With the development of DWDM technology,the system single channel transmission rate has evolved from 10Gbit/s,40Gbit/s to 100Gbit/s,so the DWDM system capacity is no longer a bottleneck in the network development.Hence,end-toend dynamic configuration and scheduling and the network security and utilization improvement have become the focus of attention.This paper briefly describes the key technologies for Wavelength Switched Optical Networks（WSON）,verifies the WSON functions through the trial network and explores the strategies for its applications.关键词：WSON;GMPLS;RWA;PCE
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发布时间： - 摘要：On the basis of building a data model for synchronization devices and clock links to simulate the timing link transmissions of synchronization networks,quantitative analysis data can be obtained for the optimization and expansion of the existing sync networks.Using the simulation software independently developed by the Electric Power Research Institute of China,this paper analyzes the adaptability of the State Grid 1st-level backbone network structure to the clock synchronization and the clock state of the network nodes and links after clock optimization and adjustment,calculates the statistical results of the ultra-long link phase errors and detects the erroneous clock setting,providing forceful data support for the planning and construction of synchronization networks.关键词：synchronous simulation;phase error calculate;clock
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发布时间： - 摘要：At the present,Gigabit Passive Optical Network（GPON）broadband access is an ideal approach to tri-network（voice,video and high-speed data）convergence or triple play.This paper presents a PAS7401V-based Optical Network Unit（ONU）voice,data and video service access implementation method.In this method,voice access is implemented by using Voice over Internet Packet（VoIP）scheme,which ensures the QoS of voice transmission and the service interface conform to the relevant performance requirements;data is accessed over the 10/100/1 000Mbit/s Ethernet,so is video.It focuses on the design of PAS7401V-based ONU software and hardware and tests the system throughout,packet loss rate and forwarding latency in ONU systems,verifying the correctness of the design scheme,and voice interface performance test results indicate that the proposed scheme runs well on GPON.关键词：GPON;VoIP;OLT;ONU
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发布时间： - 摘要：Packet Transport Network（PTN）is a new generation IP-based packet optical transport network technology.This paper builds the corresponding mathematical models for the traffics predictions of the core layer,convergence layer and access layer of the metropolitan area PTN.On the basis of these models,it carries out traffic prediction and bandwidth calculation and proposes a relevant strategy for the PTN traffic control,which has a certain reference value for guiding the PTN construction and service provisioning and configuration in the operation and maintenance period.关键词：PTN;QoS;traffic prediction;traffic control
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发布时间： - 摘要：In line with the application requirements for the all-optical encryption of the single-wavelength signals in optical transmission systems,this paper makes a theoretical analysis of the all-optical encryption technology for the physical layer of the optical transmission system on the basis of the flow cryptosystems,designs an experimental scheme for SOA-XGM-based all-optical A logic gate and erects an experimental system in the laboratory.Moreover,it realizes the A logic processing at10Gbit/s,analyzes the effects of such main parameters as detected and pumped optical signal powers and SOA injected current on the quality of the output signals from the logic gate and implements the all-optical encryption of plain optical signals.关键词：SOA;XGM;all-optical A logic gate;all-optical encryption technology
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发布时间： - 摘要：This letter introduces the design and preparation of a novel non-photonic crystal structured and bend-insensitive singlemode optical fiber.It numerically analyzes the trench waveguide structure of the fiber and obtains by using the PCVD process its sample with a MFD of 4.3μm at 1 310 nm and 5.4μm at 1 550 nm,and a splicing loss with G.652 Dfiber as low as0.15dB/2joints,satisfying the splicing requirements of common jumpers.When this sample is wound 10 turns with a bend radius of 2.5mm,its bending loss is optimized to 0.01 dB at 1 550 nm,satisfying any harsh FTTx application environment.Furthermore,it has the potential to replace copper cables as an ideal transmission medium in consumer electronics and to be applied in various photoelectronic devices.关键词：ultra-low bending loss;active optical cable;optical fiber;FTTH
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发布时间： - 摘要：A high birefringent hybrid lattice Photonic Crystal Fiber（PCF）with modified circular and rectangular air holes is proposed.When the air holes are filled with the thermo-sensitive fluid,the variations of its birefringence properties with temperature are investigated by using the finite-element method-based Comsol software.The research results show that when the circular air holes in the core area are filled with ethanol and the pitch of holesΛ =1μm,the diameter of circular air holes D =0.96μm and the aspect ratio of rectangular air holes a/b=4,the thermo sensibility of the PCF at excitation wavelengthλ=1 550 nm reaches 10-5.The proposed fiber has broad application prospects in PCF temperature sensors with high sensitivity.关键词：PCF;hybrid lattice;ethanol-filling;high sensitivity;temperature sensing
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发布时间： - 摘要：THz communication has important applications in high-speed ultra wideband wireless access networks.As one of the key devices in the THz communication systems,its study is of major significance.This paper proposes a novel compound lattice photonic crystal-based multi-wavelength THz optical switch,which can effectively perform the on/off control of quadruplewavelength THz waves.Simulation is conducted by using the FDTD method in the RSOFT.The results show that its extinction ratio is 40 dB,the insertion loss 0.109 dB and the switching rate 5.55 GHz and it has important application potential in future wireless optical communications.关键词：multi-wavelength;photonic crystal;THz wave;compound lattice;optical switch
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发布时间： - 摘要：This paper presents the structural design of a novel liquid crystal technology-based Wavelength Selective Cross-Connect（WSC）,which realizes 2×4flex-grid WSC by means of polarization multiplexing on the basis of the conventional 1×N WSC,thus reducing the number of the devices required for system networking,improving the system integration level and lowering the networking cost.Theoretical analysis and experimental results verify that total insertion loss of this WSC is less than5 dB and the 3dB bandwidth of 50 GHz grid in operating state is greater than 40 GHz.关键词：Reconfigurable Optical Add/Drop Multiplexer（ROADM）;liquid crystal;WSC
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发布时间： - 摘要：In performing Wavelength Division Multiplexing（WDM）of the same number of channels,it is simpler to use threechannel devices than two-channel ones.This paper introduces and analyzes the new structure of an all-fiber interleaver that can perform three-channel flat output,derives its energy transmission expression and discusses in detail the effects of the variations of the coupler splitting ratio on the filtering characteristics.The results show that when the length difference between the fiber interference arms and the splitting ratio take certain fixed values,it will become a three-channel all-fiber interleaver with equal multiplexing interval and flat passband and the WDM channel interval depends solely on the size of the interference arm length difference.关键词：fiber coupler;all fiber;interleaver;flat passband
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发布时间： - 摘要：On the basis of the temperature field distribution features and thermal deformation mechanism of the external cavity tunable lasers obtained by using the finite element analysis method,this paper proposes an optimized optical bench structure and theoretically analyzes and numerically simulates its heat dissipation and thermal deformation in order to decrease the effects of the ambient temperature variations on their wavelength stabilization.The results show that the optimized structure has efficient heat transfer property and significantly reduces the effect of thermal deformation on the cavity length,thereby improving the wavelength stability of the lasers at different operating temperatures.关键词：external cavity tunable laser;finite element analysis;optical bench;structural optimization
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发布时间： - 摘要：The spectrum features of the Amplified Spontaneous Emission（ASE）of a 25cm-long Er-doped fiber pumped by980 nm LD is measured,and its ASE empirical formula is obtained from the experimental data fitting by using the L-M algorithm and the least square method.The research results indicate that the central wavelength of the two peaks in the ASE spectrum are 1 530.951 and 1 555.964 nm respectively and the goodness of fit（R-square）value reaches 0.980 72 and the residual sum of squares is 4.447 69×10-9.关键词：Er-doped fiber;ASE spectrum;spectral line broadening;function fitting
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发布时间： - 摘要：In response to the engineering requirements of optical atomic clock systems,a miniature all digital frequency stabilization circuit incorporating LD current and temperature controlled drivers is developed,which is 120mm×80mm×40mm in external volume.From the optically pumped cesium atomic system tests,a Raman-Ramsey interference pattern with high SNR can be obtained and the test results show that the frequency stabilization precision of this circuit is better than 1 MHz.关键词：optical atomic clock;LD;frequency stabilization
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发布时间： - 摘要：As few of resource allocation strategies for relay systems simultaneously consider both subcarrier pairing for multiple users and the requirements of different users,this paper proposes a multiuser subcarrier pairing and power allocation algorithm on the basis of QoS-guaranteed and proportional fairness,which guarantees both the minimum rate requirements of the QoS users and satisfies the criterion of rate proportional fairness among the Best Effort（BE）users.It first allocates the subcarriers of the second hop according to the requirements of different users,then uses the Hungarian pairing algorithm to obtain the optimum pairing of the two-hop subcarriers and finally allocates power by using the similar water-filling algorithm.Simulation results show that the proposed algorithm effectively improves the system throughput while meeting the user requirements for QoS guaranteeing and proportional fairness criterion.关键词：relay;Hungary algorithm;subcarrier pairing;proportional fairness
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发布时间： - 摘要：As frequent changes of node movement and incomplete communication paths in delay tolerant networks cause messages to be forwarded only by chance of node meeting and blind message forwarding in such networks is liable to be low in success rate without knowing the node correlation,this paper proposes a meeting closeness-based dynamic estimation strategy for delaytolerant networks.On the basis of designing a calculation model of the inter-node conditional meeting time interval and the connection duration,it determines the closeness of the inter-node relationship,defines the delay tolerant network model,constructs the shortest path selection mechanism,dynamically selects the conditional shortest path and forwards the messages.Simulation data comparisons indicate that the proposed strategy can effectively improve the network performances,increase the message delivery success rate and lower the transmission delay and load ratio.关键词：delay tolerant network;node closeness;conditional meeting time interval;conditional shortest path
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发布时间： - 摘要：This paper first proposes a RoF-based scheme for providing distributed wideband access in high-speed train compartments,which is characteristic of low transmitting power,distributed micro-cell coverage and multi-access points.Then,it builds a model by using the Finite-Difference Time-Domain（FDTD）algorithm software for the evaluation of the electromagnetic radiation effects in the compartments.In comparison with the conventional wireless access systems,the RoF-based system lowers the coupling electric field intensity in the compartments by 46dB,while causing less power consumption,thus effectively reducing the electromagnetic interference to the on-board devices.关键词：optical communication;ROF;wireless access system;electromagnetic environment
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