最新刊期
卷 ， 期 1 ， 2011
- 摘要：Most of the EPON and EOC equipment are currently managed by relatively independent Network Management Systems（NMS）.On the basis of studies on their network structure and features,this paper proposes an innovative unified management scheme for the unified management of their equipment and designs and implements the topology discovery functions of EPONEOC equipment.The test results show that this scheme enables the automatic discovery of the EPON-EOC topologic structure to be well implemented.关键词：EPON;EOC;unified network management system;network topology
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发布时间： - 摘要：This paper introduces a 521 km ultra-long span repeaterless transmission in a 2.5 Gbit/s optical transmission system by utilizing Corning SMF-28 ULL ultra-low loss optical fiber as the transmission medium and such technologies as phase chirp,forward Raman,enhanced FEC and channel associated Remote Optical Pre-pumping Amplifier（ROPA）.This is the longest transmission distance by using the ROPA technology reported so far.关键词：ultra-long span optical transmission system;ROPA;Raman amplifier;FEC;ultra-low loss optical fiber
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发布时间： - 摘要：In optical OFDM systems,signals with a large PAPR will bring about serious distortions,resulting in dramatic reduction of system BER performance.In order to reduce PAPR in OFDM systems,a new method of reserved subcarriers is presented.The simulation results show that compared with the traditional method,its PAPR reduction function is not decreased with the increase of modulation order.Characteristic of high stability and less computational complexity,it is more suitable for adaptive modulation-based optical OFDM systems.关键词：optical OFDM;PAPR;reserved subcarrier
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发布时间： - 摘要：Two new technologies for phase noise compensation introduced in this paper are digital feedforward carrier recovery for laser phase noise compensation and digital backpropagation for nonlinear phase noise compensation.The former can effectively improve the tolerable laser linewidth,while the latter reduces nonlinear phase noise and enhances transmission power by a large margin so as to improve the signal-to-noise ratio.关键词：coherent detection;phase noise;carrier synchronization;feedforward;backpropagation
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发布时间： - 摘要：We investigate by numerical simulation the effects of the initial parameter fluctuations of optical pulses and the intervals of pulse pairs on the evolution of mildly dispersion-managed soliton transmissions and find that dispersion-managed soliton pairs are always on the walk-off in relation to the initial state,and the walk-off extent is relative to the initial interval between the soliton pairs.Furthermore,the evolution of dispersion-managed optical solitons is more sensitive to the initial pulse width fluctuation than to other initial parameters,so the initial pulse width should be first determined before such systems are designed.关键词：optical communication;optical soliton;dispersion-managed;pulse parameter
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发布时间： - 摘要：In this paper,we theoretically analyze in computer simulation the effects of Polarization Mode Dispersion（PMD） on the transmission performances of soliton systems when a Phase Sensitive Amplifier（PSA） is used as an in-line amplifier.In the simulation,we numerically solved the simplified basic transmission equation and the generalized nonlinear Schrodinger equation（NLSE） and use an average-soliton system as the transmission system.The simulation results show that as the PMD coefficient increases,soliton pulse is split and broadened and its amplitude decreases,resulting in the drop of the system transmission performance.关键词：PSA;PMD;average-soliton
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- 64
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发布时间： - 摘要：In order to ensure stable,safe and efficient operation of GPON services,telecommunication operators clearly require that long shine rogue ONU detection exist in GPON systems.In response to this demand,a practical solution is proposed after in-depth researches on the authentication process of GPON ONU,by which long shine rogue ONU can be effectively detected and isolated.关键词：GPON;OLT;ONU;RSSI;PLOAM
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发布时间： - 摘要：This paper presents an analysis and simulation method for ONT Management Control Interface（OMCI） protocol in the GPON equipment development and interoperability tests.This method extends the existence range of OMCI messages so that the OMCI messages received at an Ethernet port of ONU can be processed by an analysis computer connected to the port.It is proved that this method can rapidly parses the message contents and forwarding process and thus provides an effective means for their accurate location.关键词：ONU;OMCI;simulation;encapsulation and forwarding
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- 102
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发布时间： - 摘要：In order to improve the efficiency of the real-time updating of management information at the client of the Ethernet Passive Optical Network（EPON）,this paper studies the exclusive editing mode and the way of restarting NM data adopted when the NM system edits management information at the multi-client in current project applications,analyzes the drawbacks of the system when it supports multi-client collaborative editing of management information and presents the design for the integrated configuration of the management information.This solution solves the problems in multi-client collaborative editing and ensures the reliability of configuration report.关键词：integrated configuration of management information;EPON;EMS;collaborative editing
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发布时间： - 摘要：This paper introduces the advantages and key contents of the existing switch network management and switch grouping technologies and presents a simple,convenient and efficient method for the real-time monitoring of the trap information in the devices of the group networks.In addition,it explains in detail how to collect and process the trap information reported by the member switches.关键词：Ethernet;switch;group management;trap collection
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发布时间： - 摘要：We investigate the channel estimation for ultraviolet Non-Line-Of-Sight（NLOS） communication systems and estimate the pulse response of the system channels using the Least Mean Square（LMS） algorithm in the way of adaptive filtering.Furthermore,we compare the system Bit Error Rates（BER） when the channel estimation technology is or is not adopted and conclude that the ultraviolet NLOS communication system performance is improved when the raining sequence-based channel estimation technology is used.关键词：ultraviolet non-line-of-sight communication;channel estimation;LMS;BER
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发布时间： - 摘要：On the basis of fiber dispersion generation mechanism,this paper discusses the theory and method for dispersion restriction and compares the advantages and disadvantages of two linear dispersion technologies,i.e.the Dispersion Compensation Fiber（DCF） and chirped fiber grating in connection with the practical applications of the dispersion compensation technology in the optical transmission networks of Guangdong Power Grid.On the basis of the verification of the practical applications in Guangdong optical communication networks,this paper recommends that the chirped fiber grating technology be popularized.关键词：CD;PMD;dispersion compensation;dispersion compensated fiber;chirped fiber grating
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- 115
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发布时间： - 摘要：Harmonic and intermodulation distortions may be resulted from the transmission of multi-channel RF analog signals on multimode fiber-optic links.In this paper,the factors causing composite second-order distortions are analyzed and thus the spectrum characteristic of the received power obtained on the basis of deducing the expressions of the harmonic and intermodulation distortions in multimode fiber-optic links.The results show that multi-channel RF signals can be transmitted over short or middle-range multimode fiber-optic links by using the subcarrier multiplexing technology when the composite second-order distortion value is below-50 dBc.关键词：multimode fiber;optical signal transmission;subcarrier multiplexing;composite second-order distortion
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发布时间： - 摘要：This paper proposes a new type of THz composite Plastic Photonic Crystal Fiber（THz-PPCF）,the cladding of which consists of two kinds of periodically lined air holes with different diameters,and analyzes its dispersion properties by using the Finite-Difference Time-Domain（FDTD） method.The results show that a low-loss super-flattened dispersion THz-PPCF can be achieved by optimizing the air hole diameters and the lattice constant.关键词：THz-PPCF;composite structure;super-flattened dispersion;FDTD
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发布时间： - 摘要：This paper simulates the generation of superocntinuum in photonic crystal fibers using the split-step Fourier method and analyzes the mechanism of its generation and its characteristics in different photonic crystal fibers.The analytical results indicate that high quality supercontinuum spectrum can be obtained in normal dispersion regions and photonic crystal fibers can be optimized by varying their structure parameters.A supercontinuum spectrum with 210 nm bandwidth,3 dB spectral flatness is obtained at 1 550 nm region by injecting the optical Gaussian pulses with 100 fs width and 500 W peak power into a 10 m long optimized photonic crystal fiber.关键词：optical communication;supercontinuum;effective index;photonic crystal fiber
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发布时间： - 摘要：The effects of introducing an air-rod into two-dimensional air-hole photonic crystal waveguides on their optical propagation characteristics are investigated by using the Finite Difference Time Domain（FDTD） method.The results show that its transmission characteristics change dramatically with the variation of the radius of the air-rod and its position in the waveguides.In the high frequency band（above 0.26）,its transmission coefficient decreases rapidly and the larger the radius and closer to the incident source,the lower the transmission coefficient.The calculated results are verified by numerical simulation.关键词：photonic crystal waveguide;transmission characteristic;FDTD method
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- 232
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发布时间： - 摘要：As the dynamic range of the OTDR tests for long-range optical cable lines are limited,a bidirectional OTDR-based test method is presented and a test system established,in which two monitor stations are placed at the ends of a line under test.The resulted test curves are fitted at the monitor center and the fitted test curve reflects the performances of the line.关键词：OTDR;bidirectional test;optical cable performance
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发布时间： - 摘要：On the basis of the wavelength tuning principle of Sampled Grating Distributed Bragg Reflector（SGDBR） lasers,an automatic wavelength control system for SGDBR lasers is designed.This system is used for accurate and rapid wavelength scanning on our self-developed SGDBR lasers,which prepares necessary conditions for dynamic performance tests of the devices.关键词：SGDBR laser;automatic wavelength control;wavelength scanning
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发布时间： - 摘要：In view of the demerits of the present fiber-optic transceivers,this paper designs a new type of fiber-optic transceiver with the ARM LPC2210 embedded processor and IP113S Optical & Electronic Media Converter（OEMC） chip as the core and having its remote network management on the μCLinux OS platform.This system supports multi-level NM mode.Experiments show that this system achieves the expected goal and satisfies the requirement for real-time operation and has such advantages of stable performance and strong management functions.关键词：embedded systems;network management;fiber-optic transceiver
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发布时间： - 摘要：The operating mechanism of OTDR-based spiral distributed fiber-optic sensor is analyzed and the fitting curve of macrobend optical loss versus shift and its relationship with the operating wavelength and spiral bar diameter obtained by experiments.The research results show that the sensor is characteristic of large monitoring range and highly accurate location and its monitoring range and performances can be further improved by optimizing its working wavelength and spiral bar size.关键词：fiber-optic communications;distributed fiber-optic sensor;OTDR;macrobend loss
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发布时间： - 摘要：In view of the effects of temperature on silicon piezoresistive pressure sensor output,this paper proposes a novel method for pressure sensor temperature compensation by combining Principal Component Analysis（PCA） with improved BP neural networks.In this method,the prime information in temperature compensation is extracted by using PCA so that the multi-dimensional problem is simplified and the noise error in data eliminated and the neural network improved so as to bring its strong generalization and fault-tolerance capabilities into full play.The research results show that this method can restrain the effects of temperature on pressure sensors effectively and enhance their stability and accuracy.关键词：temperature compensation;PCA;neural network;sensor
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发布时间： - 摘要：A new two-dimensional optical orthogonal code,i.e.MSPC/OCS is constructed with Modified Square Prime Code（MSPC） as time spreading sequence and One-Coincidence Sequence（OCS） as wavelength hopping sequence.The cross-correlative mean value is deduced by analyzing its performance and the code is theoretically analyzed,simulated and compared.The results show that when the code weight and the minimum gap between the two adjacent chip wavelengths are constant,the increase of the number of hopping codes does not only reduce the BER of MSPC/OCS,but also increase the code word capacity.Compared with PC/OCS,MSPC /OCS is better in performance.关键词：OCDMA;MSPC;OCS;BER
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发布时间： - 摘要：In view of the continuously growing demands for such new mobile applications as high-rate data,high-quality audio and video data,a novel service-based smart handoff method for Access Point（AP） forwarding mode is proposed.The forwarding mode is dynamically decided by adding a dedicated adjacent AP-state table and a smart handoff module in an AP of a WLAN to decrease transmission delay and improve the user experience of different services so as to optimize the existing handoff mode.Its performance tests are performed in a WLAN laboratory,the results of which prove that the data transmission delay can be dramatically reduced by using this method.关键词：AP;smart handoff;service identification;forwarding mode;WLAN
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