最新刊期
卷 ， 期 1 ， 2010
- 摘要：On the basis of the calculation model for N-channel Stimulated Raman Scattering（SRS） effects under the conditions of attenuation,dispersive walk-away and SRS,this article analyzes by numerical simulation the coupling effects of SRS on the performance of DWDM fiber-optic communication systems and the relevance between the input power,number of channels and SRS coupling effect,which is of major importance to the further study on this subject.关键词：SRS;input power;Raman cross-talk;SNR
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- 86
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发布时间： - 摘要：In view of the survivable traffic grooming due to single link failures in WDM networks,this paper presents a novel lightpath-based dynamic restoration mechanism,which reserves no resources.When a link failure occurs,it restores the failure by dynamic discovery of network resources and reroutes the failed lightpath to a new lightpath or other available ones.Simulation results show that the proposed scheme has a high restoration performance.关键词：fiber-optic communication;dynamic restoration;traffic grooming;survivability
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发布时间： - 摘要：In this paper,a 3-layer PSO-trained BP Artificial Neural Networks（ANN） model is proposed for the on-line prediction of Bandwidth on Demand（BoD） ASON services and the Particle Swarm Optimization（PSO） algorithm improved.Particles with poor fitness are imposed with disturbances at random and then the disturbance effect is evaluated.The improved particles are accepted and at the same time the degenerated ones are also accepted in a certain probability.The maximum of the three predicted data is considered as the future bandwidth distribution,thus reducing the blocking rate of the bursting service.The simulation results show that this prediction model is appropriate for the on-line prediction of bursting and diversified BoD services.关键词：BoD;ASON;ANN;PSO
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发布时间： - 摘要：This article proposes a multi-order-gradient-based link aggregation algorithm and a processing mode to help the judgment of the connection setup requests,by which the original information can be approximately and without error embodied and accurate information provided for the multi-domain routing.Simulation results indicate that the error acceptance and rejection rates for the connection setup requests can be greatly reduced and the utilization ratio of the network resources and the overall network performance improved by using the proposed algorithm and processing mode.关键词：multi-domain optical network;topological aggregation;multi-order gradient
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发布时间： - 摘要：A cost-effective solution for flexible access is very important for FTTH network deployment.Transceivers at the user premises and wavelength distribution schemes are crucial for WDM-PON.Bidirectional single-fiber single-wavelength transmission schemes can considerably simplify the network structure and reduce the average access cost of each customer,but Rayleigh backscattering crosstalk has a serious effect on the system.This article analyzes various solutions for ONU light source and several solutions for suppressing Rayleigh backscattering effect.关键词：FTTH;access network;colorless ONU;Rayleigh backscatter
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- 142
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发布时间： - 摘要：In comprehensive consideration of such factors as the hops and length of bursting packets,a novel QoS-guaranteed Optical Burst Switching（OBS）-based data scheduling protocol named Hops-Preemptive Prioritized Just Enough Time（H-PPJET） protocol is proposed in this paper.H-PPJET is simulated in the OBS network scenario and compared with PPJET protocol.The simulation results show that the H-PPJET protocol outperforms PPJET in terms of network throughput and packet loss rate.关键词：scheduling protocol;PPJET;OBS network;QoS
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- 58
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发布时间： - 摘要：In this paper,a Symbian platform-based IP Multimedia Subsystem（IMS） terminal is designed and implemented,realizing voice communication services.The overall design scheme for the IMS terminal is given and the implementation procedure for the voice communication module introduced in detail.Test results indicate that this software operates reliably and the code is effective and scalable,laying a good foundation for the further development of the software.关键词：IMS;IMS terminal;voice communication
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发布时间： - 摘要：Forward Error Correction（FEC） is widely used in communication systems.In the Gigabit Passive Optical Networks（GPON）,the transmit bandwidth of ONUs is dynamically allocated,so OLT receiver should be able to decode RS（255,239） and its shortened codewords.This paper introduces a new scheme of RS decoder,which transfers data from its original low clock domain to a high one,and finally decodes the data stream with its mother code.It can complete FEC decoding in low hardware complexity.关键词：GPON;FEC;Reed-Solomon decoding
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- 111
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发布时间： - 摘要：A bottleneck appears when conventional Optical Time Domain Reflectometer（OTDR） technology is used to monitor various branches of the Passive Optical Network（PON）,a point-to-multipoint optical access technology.In this paper,on the basis of analyzing the shortcomings of several existing solutions,a novel scheme is presented,in which each ONU-line is selected and tested by driving optical switch installed in ODN and powered by light-supply installed in OLT.关键词：PON;cable monitoring;OTDR;light supply
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发布时间： - 摘要：With the acceleration of the process of building IP technology-based mobile communication networks and increasingly intensified competitions in all-service operation,China Mobile has made great effort to study and explore the all-service operation mode and technologies in order to meet the market demand.On the basis of analyzing the technological characteristics and advantages of Packet Transmission Networks（PTN）,this article presents an appropriate construction scheme and mode for Wuhan Mobile to build Packet Metropolitan Networks（PMN）.关键词：all-service operation;PMN;PTN;time synchronization;forward-compatible MSTP
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发布时间： - 摘要：This paper introduces a portable dynamic fiber-optic transmission system.With a single-wavelength bidirectional optical trans-receiver as its core and a small fiber clew,this system implements dynamic fiber payout and message transmission.Experimental results indicate that its fiber payout is safe and reliable and its transmission performance is good,making this system appropriate for personal operation in the field.关键词：optical fiber clew;dynamic transmission;winding and payout
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发布时间： - 摘要：The influence of third-order dispersion on fundamental optical soliton propagation in monomode fibers is studied by the numerical solution of the nonlinear Schrodinger equation.The results show that due to the effect of third-order dispersion,the fundamental soliton pulses are broadened in the propagation,the peak energy gradually decreased,the pulse shape distorted,the center of the pulses shifted sideward and an unsymmetrical trailing oscillatory structure formed.With the additional effect of second order dispersion,the resulted pulse oscillation will be mitigated.In consideration of the nonlinear effect,the peak power decline arising from the dispersion effects is to a certain extent compensated and the generation of unsymmetrical trailing is inhibited.关键词：fiber optics;fundamental soliton pulse;third-order dispersion;nonlinear effect
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- 145
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发布时间： - 摘要：The route detection and fault location technology for submarine optical cables is one of the key technologies in under-sea cable maintenance.In view of the shortcomings and insufficiency of the present commonly used detection methods,this paper proposes a passive submarine optical cable route detection technology.It introduces its system principle,presents the design scheme and gives the effective simulation method and simulation results.The results indicate that the larger the voltage decline slope,the farther the distance between the coil and the cables,enabling the system to effectively carry on route tracking and fault location.关键词：submarine optical cable;route detection;electromagnetic induction;eddy current
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- 102
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发布时间： - 摘要：With the development of broadband access technology,especially of FTTH technology,daily increasing importance is attached to the flame retarding characteristics of the electrical and optical communication cables,which are laid in or under such places as ceiling,metope,building silo,floor and carpet,This article introduces the relevant specifications concerning the flame spread tests included in the latest version of Standard GB/T18380 to help the related technicians understand and master the test methods and quality control of electrical and optical cables.关键词：electrical and optical communication cable;standards of flame propagation;FTTH
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发布时间： - 摘要：A Semiconductor Optical Amplifier（SOA）-based multi-wavelength fiber ring laser using frequency shifted feedback technology is reported in this paper,in which an Acousto-Optic Modulator（AOM） is incorporated as a frequency shifter and a Mach-Zehnder（M-Z） fiber interferometer is used as a comb filter.54 50 GHz-spaced stable continuous multi-wavelength optical lasing in a range of 1.5 dB output optical spectrum and 21.7 nm bandwidth are obtained with an extinction ratio of 28 dB.This laser is characteristic of stable operation,wide output optical spectrum and low output power variations.Experimental results indicate that effective gain equalization between different lasing oscillations is achieved and the output optical spectrum bandwidth increased by 21.7% by using this technology.关键词：laser technology;multi-wavelength laser;semiconductor optical amplifier;frequency shifted feedback
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- 125
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发布时间： - 摘要：Effects of birefringent dispersion on the capability of a liquid crystal Variable Optical Attenuator（VOA） are analyzed by the Jones matrix method.The results indicate that birefringent dispersion greatly weakens its attenuating capability when working on lasers with narrow linewidths.But when it works on lasers with wider linewidths,the effects are negligible,but inevitably accompanied with a fading attenuating capability.Therefore,it is appropriate that liquid crystal VOA work on lasers with narrow linewidths and that full consideration be given to the effects of birefringent dispersion on VOA attenuating capability in its design and application.关键词：liquid crystal;VOA;birefringent dispersion;linewidth;attenuating capability
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- 129
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发布时间： - 摘要：The control algorithm for QHQ-typed direction-controlled polarization controllers is discussed in this paper.Simulation results show that this algorithm is ergodic.Error analysis is carried out on the correlativity between their retardation and wavelength.The result is very important for the analysis of their error compensation and improving their accuracy关键词：polarization controller;direction control;error analysis
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- 185
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发布时间： - 摘要：On the basis of the analysis of the effects of high-power Er-Yb co-doped double-clad optical fiber amplifiers on multi-wavelength signal transmission properties and especially of the investigations of multi-wavelength signal degeneration at different optical power levels,the optical nonlinearities at high power levels and the laws in specific applications are analyzed and some helpful conclusions are obtained,providing certain basis for the transmission of high power multi-wavelength optical signals.关键词：double clad fiber;nonlinearity;power penalty
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- 78
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发布时间： - 摘要：This paper introduces a transmission design scheme for the remote pumping in DWDM ultra-long-haul communication systems.In order to obtain high gain and low noise figure,we adopt Er-doped fibers,which are characteristic of small numerical aperture and low doping concentration,and use a dichroscope that reflect all pumping light and transmits all signal light to increase the utilization ratio of the pumped light.Thanks to the optimized lightpath design,we obtain a remote pumping amplifier with a gain of >17 dB and noise figure of <7 dB.关键词：remote pumping system;Er-doped fiber;noise figure;pumping amplifier
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发布时间： - 摘要：Introducing the phase distribution of fiber grating and taking into consideration the back-and-forth phase shift of the light in the external cavity,this paper analyzes the influence of temperature and the length of the external cavity on the Fiber Bragg Grating（FBG）-External Cavity semiconductor Lasers（ECL） mode by using four-order Runge-Kutta method.The numerical simulation results show that the number of the FBG-ECL mode increases and the intermode spacing decreases with the increase of temperature and external cavity length and the influence of the changes of the external cavity length on the hopping of the FBG-ECL mode becomes obvious.关键词：fiber grating;Semiconductor laser;temperature;mode hopping
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发布时间： - 摘要：In this paper,the two-value problem in fiber-optic displacement sensors based on the principle of collimated beam reflective intensity modulation is investigated.In order to solve this problem,a photosensitive component is set on its surface to indicate the range of its movement.For the purpose of eliminating such effects as fluctuations of the light source and the reflectivity difference of the reflective plane on the measuring results,a double lightpath structure is designed.Moreover,a C8051F410/2 microcontroller-based circuit of signal detection hardware is presented.关键词：collimated beam;two-value problem;double optical paths
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- 171
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发布时间： - 摘要：On the basis of the theoretical model for the alignment of single-mode optical fiber array with the planar optical waveguide,simulations of two position search methods,i.e.hill climbing method and pattern search method,commonly used in accurate alignment processes are conducted.The results indicate that the maximum optical power value can be faster searched by the pattern search method and the convergence of the algorithm is significantly higher than by the hill climbing method.关键词：precision targeting;hill climbing method;patter search method
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