最新刊期
卷 ， 期 3 ， 2009
- 摘要：Signal multiplexing and mapping and the use of 3R regenerator and other technologies give rise to jitters in Optical Transport Networks（OTN）,which affect the quality of network signals.This thesis analyzes payload signal mapping jitters and jitter accumulation in signal transmission after multiple OTN islands.It first sets up an analytical model on the basis of practical applications,then obtains an analytical formula for the jitters accumulation in the time domain on the basis of analyzing the model and finally achieves the results by simulation.
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发布时间： - 摘要：As Ethernet Passive Optical Network（EPON） has become one of the most widely used technologies for broadband access,it is necessary to equip it with a strong network management system.In order to satisfy the demand for enhanced source management of EPON,a resource management subsystem is designed,so as to implement real-time supervision for the management and status of the network resource.This paper first introduces the overall architecture of the EPON management system,then describes the design scheme for the resource management subsystem and finally realizes it at the NM client end,server end and the agent side.关键词：EPON;SNMP;resource management;frame chart
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发布时间： - 摘要：The 40 Gbit/s WDM system has begun to be commercially deployed.Differential Quadrature Phase Shift Keying（DQPSK） has higher spectral efficiency and greater robustness to chromatic and polarization mode dispersion than On-Off Keying（OOK）.Starting with the transmission performance requirements of the 40 Gbit/s WDM system,the paper analyzes the principle and implementation approach and verifies its transmission performances by accurate simulation.关键词：WDM;DQPSK;PMD
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发布时间： - 摘要：This paper introduces a number of the main implementation methods for the Tunable Dispersion Compensation（TDC） and makes comparisons between them.Then it makes a detailed description of the applications of the TDC modules in various scenarios in DWDM systems and gives the relevant application models.Finally,it summarizes the development goal of the TDC technology in DWDM system applications.关键词：TDC;DWDM;BER
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发布时间： - 摘要：This article reviews the ultrashort optical pulse generation technology for high-rate optical networks and its progress,discusses the approach for the implementation of highly efficient pulse compression and introduces the results in the research on the optical pulse compression method by replacing the decreasing-dispersion fiber loop mirror with step-decreasing dispersion fiber loop mirror.Numerical calculations indicate that the compression effect by the proposed method is basically identical to that by using the dispersion decreasing fiber loop mirror.It not only resolves the difficulties in the manufacture and selection of step-decreasing dispersion fibers but also brings about convenience for the system design.Finally,it presents some suggestions for the improvement of pulse compression.关键词：pulse compression;dispersion decreasing fiber;ultrashort optical pulse
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发布时间： - 摘要：In IP over WDM networks,the optical network can dynamically provide the IP network with bandwidths by setting up a new lightpath.It is an important goal for traffic grooming to maximize the profit of the service provider by utilizing the limited resources of the optical network.In this work,on the basis of the overlay network model,we study the access mechanism for the IP/MPLS over WDM networks and try to develop an algorithm that can provide differentiated services to them without impacting the overall network efficiency.关键词：DiffServ;traffic grooming;lightpath
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发布时间： - 摘要：In this paper,simulations verify that when DPSK demodulation is conducted,better transmission performances can be achieved and the optimal FSR value obtained by adjusting the relative delay of the two arms of the Delay Line Interferometer（DLI） for optimizing the Free Spectrum Range（FSR） so as to make it greater than the transmission bit rate,than those by the conventional 1 bit delay.Besides,the DPSK system after FSR optimization is improved in both OSNR sensitivity and dispersion tolerance.However,its suppression effect on PMD is not obviously enhanced.关键词：DPSK;DLI;FSR;OSNR
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- 111
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发布时间： - 摘要：The PON system commonly adopts point-to-multipoint tree topology.As its trunk fiber survivability has a bearing on the reliability of the entire PON system,its protection is essential.This paper presents an Optical Line Protector for PON systems（OLP-P） that features in low cost and automatic switching and conducts two experiments to verify its automatic switching function,switching time and the automatic switching function and wait-to-restore time in the PON system.关键词：optical line protection;PON;reliability
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- 104
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- 3
发布时间： - 摘要：The generation and development of the SIP-based IP Multimedia System（IMS） enable the convergence of fixed and mobile networks and it has become a crucial issue to provide QoS guarantee for the multimedia services of such a new type of network.In view of the simplification and easy extension of SIP,this paper presents a novel scheme for the improvement of IMS QoS by using SIP extension.关键词：IMS;QoS;SIP;protocol extension
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- 81
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发布时间： - 摘要：The implementation of efficient failure management relies on the information collected from the network.In transparent optical networks,such information is delivered by the monitoring equipment.Failures in such networks can be located by encoding on the basis of analyzing the performances of the optical and monitoring devices.The failure location algorithm used in this paper can cope with both the ideal scenarios（no false and/or lost alarms）,and nonideal scenarios（having false and/or lost alarms）,thus improving the accuracy of failure location.关键词：transparent networks;failure management;failure location
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发布时间： - 摘要：As a fiber-optic access network technology that has a broad application prospect,the Ethernet Passive Optical Network（EPON） has been more and more widely used in access networks.In this paper,we propose to introduce WLAN technology into EPON so as to provide wireless access services in EPON.Theoretical analysis of the feasibility of this integration is given,the proposed system architecture described and the feasibility and effectiveness of the proposed integrated system verified by system tests.关键词：EPON;WLAN;broadband access network
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- 105
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发布时间： - 摘要：In this paper,a tentative idea on the convergence of fiber-optic communication networks with sensor networks is presented,i.e.transmitting the sensor signals delivered in the sensor networks in the channels of the existing OAN.It first analyzes the feasibility of this idea.Then it puts forward a method for the coupling of sensor signals with communication signals according to that for the fixed frame multiplexing,sets up the basic network architecture of this system according to that of the existing OAN and analyzes the time slot and bandwidth allotment in the above-mentioned multiplexing.关键词：communication network;sensor network;OAN;sensor signal
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发布时间： - 摘要：In this paper,a kind of 10 Gbit/s SFP+（Small Form Pluggable plus）optical transceiver module is reported.Consisting of a TOSA,a ROSA and a control circuit,it is capable of intelligentized control and module status supervision.Tests are performed in accordance with the SFF-8431 protocol,the results of which show that this transceiver satisfies the application requirements of 10 Gbit/s Ethernet and can support the data rate of 11.3 Gbit/s to the maximum.关键词：SFP+ optical transceiver module;SFF-8431 protocol;intelligentized control
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- 539
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发布时间： - 摘要：The propagation and chirp characteristics of the fundamental soliton pulse in the Erbium-Doped Fiber Amplifier（EDFA） in the anomalous-dispersion regime are numerically studied and a novel method for achieving linear chirp by using EDFA proposed.The results of the numerical analysis show that good linear chirp is obtained when the gain coefficient μ is far greater than 1 and the chirp characteristics are affected by the length L of the selected EDFA: the larger the value of L,the more obvious the linear chirp,but the narrower pulse region it takes.Finally,the compression factor and pedestal energy ratio of the output pulse obtained after chirp compensation are calculated.关键词：nonlinear optics;linear chirp;EDFA;pulse compression
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发布时间： - 摘要：A directional coupling power splitter is formed when three parallel monomode waveguides are introduced in perfect triangle photonic crystals.When the refractive indexes of the dielectric columns between the waveguides in the coupling zone are asymmetrically changed,the output energy ratio at the energy output ports will be altered.FDTD-based numerical simulation results indicate that when the refractive index is changed in small amounts,the splitter will have a higher energy transmission ratio and the output energy ratio can be adjusted in a certain range.关键词：photonic crystal;directional coupling power splitter;energy output ratio
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- 142
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发布时间： - 摘要：On the basis of the operating principle of BOTDR and the data of the commonly used Ф 0.9SM single-core tight-tube fiber in the lab at the constant temperature,this paper performs calibration and analysis of the influence of the ambient temperature on the monitored data by using statistical analysis and linear regression method,effectively rejecting the pseudostrain on the data caused by the ambient temperature influence and achieving good results.关键词：BOTDR;Ф 0.9SM single-core tight-tube fiber;temperature;calibration
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- 162
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发布时间： - 摘要：This paper introduces a new method for testing the coating uniformity of object surface coating uniformity on the basis of analyzing the interrelations between reflective optical power and object surface coating thickness and uniformity on the basis of the principle of geometrical optics.To fit in with the randomness of surface coating,this sensor can be used for online tests on coating uniformity in different areas.On the basis of theoretical analysis,it sets up an experimental testing system.The test results show that changes in the uniformity of surface coating can be reflected by using this sensor with an accuracy of as high as 10 μm,holding out a good prospects for practical application in the future.关键词：fiber sensor;surface coating;uniformity;online test
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- 150
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发布时间： - 摘要：In this paper,the principle of multifrequency acoustooptic diffraction is first introduced.Then,the accoustooptic diffraction coupling wave formula is deduced and in combination with the analysis of its vectors,the multifrequency acoustooptic diffraction effects,such as diffraction efficiency,wave vector mismatch and 3rd-order intermodulation,are quantitatively and qualitatively analyzed.Experimental results show that all these effects are in good agreement with the Bragg theoretical limits.关键词：multifrequency acoustooptic diffraction;coupled wave formula;cross modulation;intermodulation intensity;diffraction efficiency
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- 131
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- 3
发布时间： - 摘要：As a low-cost and high-performance specific wavelength light source used for fiber-optic communication systems,the Vertical Cavity Surface Emitting Laser（VCSEL） is simple to test and easy to couple and form arrays.It has been applied in large scales in optical parallel interconnection and high-density light storage.This paper introduces its structure and the current level of its fabricating technology and explains its present development and applications in various wavebands,discusses the scopes of its applications in different fields and points out the prospects of its development.关键词：VCSEL;DBR;optical interconnection
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- 429
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发布时间： - 摘要：Handoff delay and data packet loss are always the key factors in restricting the development of mobile IPv6.In this paper,the problems with the existing handoff algorithms are analyzed,on the basis of which an improved algorithm is presented.Simulation results show that by this new algorithm the initiation of the control mechanism for the communication node congestion arising from the network handoff of the mobile nodes can be effectively restrained so that the correctness and throughput of the mobile network data stream are increased and the communication quality of the mobile network improved.关键词：mobile IPv6;Home Agent（HA）;Foreign Agent（FA）;handoff delay;congestion control
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发布时间： - 摘要：When a new route is established or the route is partially serviced by the AODV routing protocol,the existing routes can be utilized.This will increase the load to the channels in these routes as data are usually just be transmitted in them,thus causing congestion,while there may exist idle routes but not utilized.In this paper,we propose an ameliorative-AODV routing protocol,by which the newly established route will be diverted from the heavily loaded nodes or sections and select the relatively idle ones in line with the queue lengths buffered in the intermediate nodes so as to equalize the network loads and improve the entire network transmission efficiency.关键词：AODV routing protocol;buffered queue length;congestion
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发布时间： - 摘要：At the present,most of the mobile ad hoc routing protocols select their routes on the basis of single-path routings with the shortest hops.In terms of energy,they fail to make full use of the network resources.In this paper,a Multipath Saving Dynamic Source Routing（MSDR） protocol is proposed.The experimental results show that this protocol does not only improve the network reliability,but also effectively prolong the operating time of the nodes and the lifetime of the network.关键词：mobile Ad Hoc;wireless sensor network;routing protocol
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发布时间： - 摘要：The applications of the pre-bonding PCB technique improves the product consistency in mass production of RF power amplifier modules,but at the same time it brings about new problems in the device grounding,i.e.poor grounding leads to poor performances and instability of the devices.This paper theoretically analyzes the causes for the problems of the new technique on the basis of the comparison between the conventional techniques and the pre-bonding PCB technique and proposes a simple and feasible solution,thus making this technique successfully applied in the production of the above-mentioned modules.关键词：pre-bonding PCB;RF power amplifier;grounding;simulation
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