最新刊期
卷 ， 期 2 ， 2010
- 摘要：In view of the fiber-based all-optical regeneration based on Self-Phase Modulation（SPM） and Four-Wave Mixing（FWM） effects,this paper analyzes the limitation of regeneration towards RZ-DPSK modulation signals using SPM effect.This method can be used only when phase modulation is transformed to amplitude modulation.At the same time,it investigates the relationship to be met among pumped light,signal optical wavelength and zero-dispersion wavelength on the premise of high transformation efficiency by utilizing the FWM effect so as to insure the proper transfer function of regeneration.关键词：all-optical regeneration;RZ-DPSK;SPM;FWM
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- 136
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发布时间： - 摘要：An algorithm for the calculation of Offset Time（OT） by using the enhanced learning mechanism is presented in accordance with the flexible OT setting required by the network load and QoS in the Just-Enough-Time（JET）-signaling-based buffer-less Optical Bursting Switching（OBS） networks so as to enable OT to be self-adapted in line with the variations of the network load and support QoS so that it can adapt itself to the changes of the network status.Simulation results show that the end-to-end delay and blocking ratio in different network statuses can be effectively reduced and QoS well provided by using this algorithm.关键词：OBS;JET;offset-time;enhanced learning algorithm
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- 55
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发布时间： - 摘要：In WDM optical networks,the nodes are sorted on the basis of the total length of the shortest path passing the nodes as the weight and then the existing "subgraph+ ADD" algorithm is improved by using the heuristic idea of nodes with longer total path length first,resulting in a new subgraph+PLS algorithm.Computer simulation results show that the new algorithm effectively reduces time complexity in operations while retaining the accuracy of the results.关键词：WDM;wavelength converter;subgraph;ADD algorithm
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发布时间： - 摘要：In this paper,we analyze the main factors that affect the performances of fiber-optic communication systems,set up the simulation model of the single-mode fiber channels on the basis of theoretical analysis,introduce the basic structure of the Division Feedback Equalizer（DFE） and the LMS algorithm and imitate by using the MATLAB software the adaptive equalization performances of 10 Gbit/s fiber channels using the LMS algorithm.Simulation results indicate that the LMS algorithm is simple and efficient and can effectively eliminate the inter-symbol interference caused by fiber dispersion and Polarization Mode Dispersion（PMD）,appropriate for fiber-optic communication systems that require high equalization speed.关键词：optical fiber;adaptive equalization;dispersion compensation;LMS
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发布时间： - 摘要：In view of the limitations in current researches on traffic grooming for WDM optical networks,a multi-priority QoS supported traffic grooming algorithm is proposed and studied in this paper.On the basis of the QoS requirement of traffic flow,the priority of the traffic is classified by this algorithm and arriving connection requests are routed over the paths with the least number of hops.Simulation results show that in comparison with the existing methods,the proposed algorithm can effectively reduce the blocking probability of the delay-constraint connection requests.关键词：traffic grooming;multi-priority;QoS;rerouting
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发布时间： - 摘要：In designing and constructing star fiber-optic networks,optical splitter with different splitting ratios are designed conventionally according to the different losses of each optical line to distribute optical power unequally so that equal power reaches all optical nodes.However,every optical distributor is specially designed,not to be used universally,which is disadvantageous for design,production,backup and maintenance.Since the present optical receivers have fairly wide dynamic range of input power,allowing it to vary within a certain range,this paper proposes that optical star networks are rationally designed and constructed with optical equal distributor and introduces by examples the design and construction of multiple optical equal distribution networks.关键词：equal optical divide ratio;equal optical distributor;equal optical network;optical fiber network;network construct;network design
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- 52
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发布时间： - 摘要：Different combined modulation modes of DPSK and OOK are separately employed for the upstream and downstream links.By comparison with different modulation formats in the downstream link,20 km upstream and downstream transmission at a symmetric rate of 10 Gbit/s is realized without dispersion compensation,which shows that higher extinction ratio in the downstream link and better dispersion tolerance in the upstream link can be realized by employing the combined modulation with IRZ code so as to enhance the overall performances of the transmission system.关键词：WDM-PON;combined modulation;IRZ code;extinction ratio
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- 141
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发布时间： - 摘要：On the basis of Resilient Ethernet Ring（RER） technology,a novel ring transmission control frame structure is studied and its functional design discussed Then a model of RER is built up on a network simulation tool OPNET,which verifies the transmission effectiveness of the designed frame and is compared with the existing ring switching technologies in network throughput performance,indicating that the new technology has distinct advantages and provides simulation basis for perfecting this ring technology.关键词：RER;traffic;ring switching
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发布时间： - 摘要：In view of the deficiency of current backup resource management mechanism for Multi-Protocol Label Switching-Traffic Engineering Fast Re-Route（MPLS-TE FRR）,a one-to-one backup-based efficient Backup Resource Management（BRM） mechanism is proposed,which implements effective sharing management of the backup resources by making the key nodes in the backup path know the available information about nodes and links in limited range and at the same time support the sharing of the backup resources by both the same and different protected paths.Simulation results show that this scheme cam effectively save the backup resources and improve the utilization ratio of network resources.关键词：MPLS;one-to-one;backup resource;fast reroute;local protection
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发布时间： - 摘要：The next generation Metropolitan Area Network（MAN） tends to be based on packet and broadband transmission,but in the advance towards IP MAN,TDM and IP services will coexist for a long period of time.This paper introduces the position of and demands for mobile MAN and analyses the commonly used Packet Transport Network（PTN） technologies,such as Provider Backbone Bridge（PBB）,Provider Backbone Transmission（PBT） and Transport Multi-Protocol Label Switching（T-MPLS）.On this basis,this paper discusses the networking scheme of PTN equipment and the solutions for TD-SCDMA base station synchronization.关键词：MAN;PTN;synchronization
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- 63
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发布时间： - 摘要：We propose a novel Arrayed Fiber Grating（AFG）-based spectral beam combining configuration,which is characteristic of good single-mode properties of output light spots,combined with high system reliability and scalability.Simulation results from Gaussian approximation indicate that this configuration has high diffraction efficiency,small output light spot size and good single-mode characteristics.关键词：fiber laser;spectral beam combining;AFG;Gaussian approximation
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- 143
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- 2
发布时间： - 摘要：An all-optical wavelength converter scheme appropriate for Polarization-Shift-Keying（PolSK） is proposed on the basis of the Four-Wave Mixing（FWM） effects in Semiconductor Optical Amplifiers（SOA）.Injecting complementary light can shorten SOA gain recovery time,while amplifying saturated power improves the wavelength converting efficiency.This all-optical wavelength converter is theoretically implemented in numerical simulation and the effects of input pump light,signal light and complimentary light on the output properties of the converter are investigated.关键词：all-optical wavelength converter;FWM;PolSK;SOA
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- 105
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发布时间： - 摘要：This paper presents the concept of quasiperiodic one-dimensional photonic crystal and applies the one-dimensional finite difference domain method to the design of a narrowband filter with a mirror symmetry coupling structure constructed with one-dimensional binary quasiperiodic photonic crystal.The numeric results show that narrowband filtering can be implemented by adopting this structure.Further study indicates that in order to realize filtering at the same wavelength and with other conditions unchanged,the greater the refractive index of the coupling layer,the smaller the thickness of the mirror image coupling layer and when the coupling layer media is constant,its thickness defines the position and bandwidth of the narrowband.When other conditions are constant,the incident angle defines the position of the narrowband,the greater the incident angel,the more it moves towards the short waves.关键词：one-dimensional photonic crystal;the finite difference time domain method;mirror symmetry coupling;narrowband filter
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- 151
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发布时间： - 摘要：A limiting amplifier for 622 Mbit/s optical receiver module is designed by adopting the 0.25 μm CMOS technology.In a fully differential structure,the whole system consists of a bias circuit,an input buffer,three similar amplifier cells,an output buffer and a DC feedback.With a 3.3 V power supply,its power dissipation is about 109 mW,its circuit gain reaches 97 dB and it maintains a constant output voltage swing of 790 mV in an input dynamic range of 46 dB.关键词：622 Mbit/s optical receiver module;CMOS technology;limiting amplifier
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- 120
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发布时间： - 摘要：In this paper,a method is analyzed to calculate the backscattering optical power and frequency shift by using the electric field amplitude and frequency of the microwave signals obtained by heterodyne detection.By using this method,the fairly high power microwave signals are integrated by numerical fitting and the backscattering optical power,frequency shift and the coefficient matrix changed with the temperature and strain are calculated by using the resulted DC and AC components.The numerical results show that the demodulation precisions of the temperature and strain are 1℃ and 100 με respectively,yet restrained by certain sampling frequencies.关键词：optical fiber sensor;Brillouin scattering;heterodyne detection;temperature and strain;microwave electro-optic modulation
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- 255
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发布时间： - 摘要：In this paper,a model for Orthogonal Frequency-Division Multiplexing（OFDM）-based Radio over Fiber（ROF） system is studied by solving the Schrodinger equation by step Fourlier transform and its optical transmission performance is simulated and calculated.The effects of the dispersion and nonlinear parameters in fiber channels on signal transmission are analyzed,indicating that OFDM-ROF signals can be transmitted in fibers only by pulse compression.关键词：OFDM;ROF;chromatic dispersion;nonlinear effect;pulse compression
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- 167
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发布时间： - 摘要：In this article,on the basis of the difference set theory,the constraint conditions for the optimal optical orthogonal codes that satisfy the relativity are given,the construction method for the optimal（n,w,1） optical orthogonal code presented and the optimal（n,w,1） optical orthogonal code block with a capacity of 2 constructed.Finally,the optimal optical orthogonal code block a capacity of 60 is constructed by using the recursive algorithm.Simulation results indicate that the optical orthogonal code block constructed by this method has fairly large code capacity and good relativity,and has a certain practical applicability.关键词：optical orthogonal code;difference set;relativity;construction method
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- 117
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发布时间： - 摘要：In this paper,two kinds of double-frequency Radio over Fiber（RoF） system models are simulated.On the basis of experiments,a RoF system model,whose double-frequency waveband is directly modulated by a Mach-Zehnder modulator,is realized.Then,it is improved into a system model,whose two wavebands are modulated with two Mach-Zehnder modulators respectively.The results show that when BER=10-9 and the fiber length is 55 km,the improved system is 5 dBm better at the 40 GHz frequency band and more stable in terms of sensitivity than the former.关键词：Mach-Zehnder modulator;double-frequency waveband;ROF;BER;sensitivity
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- 207
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发布时间： - 摘要：In optical communication,high modulation level（M） of a transceiver results in its high power efficiency,yet leading to the increase of time slot rate and affecting its error performance.In this paper,the effect of the time slot rate on the error performance of the APD-based direct detection receiver is studied.In the case of pulse position modulation,the code error rate versus time slot rate is derived and the root cause of effect production analyzed.Numerical results show that the increase of time slot rate weakens the system noise rejection performance and,for example,approximately 1 dBm more average signal power is required from M to M+1 with code error rate 10-6.关键词：optical wireless communication;direct-detection;error performance;code error rate
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发布时间： - 摘要：A FBG array-based two-dimensional tunable encoder/decoder structure is presented in this paper and the system BER degraded as a result of the autocorrelation peak power degradation of the coder/decoder output in wavelength mismatch is analyzed in detail.The decoder output power and EER of the coder/decoder in corresponding wavelength mismatch with the changes of TS/WH code parameters are simulated.The analytical results show that the system BER remains to be <10-9 for Ph=31 with the wavelength mismatch of 0.1 nm,so the requirements for tuning accuracy by the coder/decoder can be decreased by increasing the number hopping wavelength.关键词：FBG array;wavelength mismatch;tunable coder/decoder;BER
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发布时间： - 摘要：This paper introduces a wireless video surveillance system based on multi-channel multimedia data transmission technology in connection with the computer network technology on the basis of the present development the modern communication technology,presents a strategy that the system uses multiple wireless modules to establish a number of communication links and dynamically adjust the data transfer mode in accordance with the communication quality of each link.This system is compatible with multiple transport protocols,thus ensuring the fluency and clarity of the multimedia data transmissions and achieving the remote network monitoring on all covered areas.关键词：multi-channel data transmission;CDMA;wireless video surveillance system
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