最新刊期
卷 ， 期 6 ， 2011
- 摘要：This paper first describes the principle of dynamic Polarization Mode Dispersion（PMD） monitoring,reviews the RF signal-,polarization degree-and nonlinear effect-based PMD monitoring technologies,and analyzes and compares their system configurations and performance indexes.Then,it points out their core principles and existing problems.Finally,it discusses the trend of their development in the future high-rate dynamic all-optical networks.关键词：PMD monitoring;RF clock;degree of polarization;nonlinear effect
- 2
- |
- 83
- |
- 3
发布时间： - 摘要：Multicast scheduling is an important factor that affects the throughput of optical multicast packet-switching nodes.As the present optical multicast scheduling algorithms discard all the blocked source multicast packets in a "one-shot" model,this paper presents a new algorithm that supports fan-out splitting on the basis of the optical packet switching architecture with limited wavelength converters shared by all the nodes.This algorithm effectively improves the utilization rates of the port resources by randomly discarding the blocked multicast packets replicated in the source node.Simulation results show that compared with the existing algorithms,this algorithm significantly increases the throughput of the optical multicast packet-switched nodes.关键词：optical packet switching;optical multicast scheduling;wavelength converter;fan-out splitting;throughput
- 6
- |
- 44
- |
- 1
发布时间： - 摘要：With the constant escalation of transmission rate,the quality of optical signals will be seriously affected owing to the accumulation of various impairments in the course of transparent transmissions,so that the signals cannot be transmitted with high QoS.In this paper,a distributed physical impairment-aware RWA algorithm is presented,which is composed of three parts,the impairment-aware routing,transmission quality sorting and allocation by priority.In this algorithm,the transmission quality evaluation in the physical layer is distributed in the hop routing and wavelength channels.Simulation results verify the effectiveness of this algorithm.关键词：distributed;physical impairment;RWA
- 2
- |
- 122
- |
- 9
发布时间： - 摘要：This paper presents a network coding-based fault location mechanism for single links in All-Optical Networks（AON）.Utilizing the advantages of the networking coding in information processing and converging,it processes signals from a single information source differently after they pass different probing paths.If the probing path sets passing through each link are different from each other,the faulty link can be located according to the probed information received at the target node.Simulation results show that this mechanism can effectively reduce the fault location cost,while ensuring the location accuracy.关键词：AON;network coding;fault location
- 2
- |
- 63
- |
- 1
发布时间： - 摘要：This paper focuses on the composition and key technology of 10 Gbit/s EPON asymmetric ONU optical modules,especially on the structure of the emitting hardware circuits and the principle of the digital Automatic Power Control（APC）,introduces the realization of the receiver section and gives a rational design scheme,which is verified in experiments.The results indicate that the optical modules designed in this scheme conform to the requirements of the international standards and can be extensively applicable in the flied of optical communications.关键词：ONU optical module;asymmetric;digital APC
- 2
- |
- 122
- |
- 3
发布时间： - 摘要：With the sharp growth of the elements in optical transmission network management systems,the element management database has low update and query efficiency,or even comes to breakdown.This paper presents an efficient distributed database system architecture,which stores data in multiple independent units by combining the master-slave and mencached technology with the distributed database,thus improving the query efficiency.This system is characteristic of large capacity,high reliability and great scalability,having significant practical application values.关键词：mass data;distributed storage;master-slave architecture;memcached
- 2
- |
- 42
- |
- 7
发布时间： - 摘要：On the basis of the Cross-Gain Modulation（XGM） effects in Semiconductor Optical Amplifiers（SOA）,we propose a scheme for realizing all optical Ultra-Wideband（UWB） Pulse Amplitude Modulation（PAM）.This scheme is simple in structure and fast in modulation as only one external optical source and one SOA are needed.We simulate the scheme using the Optisystem and analyze the impacts of the optical source power and wavelengths and the injected current to SOA and other system parameters on the PAM signal performances.关键词：UWB;PAM;SOA;XGM
- 8
- |
- 134
- |
- 10
发布时间： - 摘要：With the continuously growing demand for optical network bandwidths,multi-dimensional and multi-level modulation formats,such as 8PSK,8QAM,16QAM,have become a current focal point of research.In this paper,we make a comprehensive comparative analysis of the principles and topologies for the realization of these formats and obtain 8PSK,8QAM and 16QAM modulated optical signals by using commercially available modulation devices configured in a serial or hybrid structure.We can improve the system integration level and signal transmission performances by using configuration in a parallel structure,but it often needs multiple parallel structures,which raises harsh requirements on the cost and processes for system integration.关键词：optical communication;multi-dimensional and multi-level modulation format;PSK;QAM
- 2
- |
- 139
- |
- 4
发布时间： - 摘要：With the dramatic growth of service demand,higher requirements have been raised on the security of transmission systems that directly carry services.Characteristic of fast response and short switching time,OLP has been widely applied in high-rate optical transmission networks.However,it also brings about new problems and challenges to network maintenance and management.Starting with the principle of OLP mechanism,this paper analyzes in depth its practical problems in current network applications and proposes an innovative improvement scheme so that it can better meet the practical requirements for the quality of future services.关键词：OLP;optical line protection;chain switching
- 2
- |
- 69
- |
- 11
发布时间： - 摘要：On the basis of the OCDM and MPLS technologies,the parallel optical code-label routing technology is studied by using the separated coding/encoding scheme.The label and payload are separated by using the optical polarity characteristics and the data are coded and encoded using the FBG encoder.As the OCDM technology is adopted for the system,different payloads are permitted to be overlapped in time and the OCDM label paths on the same wavelength can be processed in parallel in the core router,thus increasing the system throughout.关键词：OCDM;optical code-label router;parallel processing;throughput
- 3
- |
- 30
- |
- 0
发布时间： - 摘要：In this paper,an asymmetrically clipping technique is proposed for the reduction of the Peak-to-Average Power Ratio（PAPR） in Optical Orthogonal Frequency Division Multiplexing（OOFDM） systems.Its main idea is to generate positive and real baseband signals that satisfy the requirements of the OOFDM systems by deleting the negative terms of the signals and clipping their peak values with the threshold levels and at the same time avoid high PAPR in the OOFDM systems with the filtering technique.Simulation results show that this algorithm can both effectively improve the PAPR features and ensure reliable system BER performance.关键词：OOFDM;PAPR;asymmetrically clipping technique
- 3
- |
- 114
- |
- 4
发布时间： - 摘要：As the conventional insertion sequence lowers the bandwidth efficiency,a superimposed training sequence timing synchronization method is proposed.Using the complex sequence in the time domain,a conjugate symmetrical structure is constructed and the sequence linearity with mirror inverse function features of the real numbers obtained after IFFT is linearly superimposes on OFDM symbols so as to remove the drawback that the traditional insertion sequence monopolizes the transmitting power.Simulation results indicate that compared with the conventional ones,this method has higher synchronization accuracy rate and improves the system spectrum efficiency in low SNR.关键词：asymmetrically clipped optical-orthogonal frequency division multiplexing;superimposed training sequence;timing synchronization
- 2
- |
- 131
- |
- 1
发布时间： - 摘要：A frequency interleaving-based DWDM-ROF system is designed,in which the idle frequency bands between the carrier and sidebands of each channel is utilized,thus improving the system spectral efficiency.At the same time,a novel demultiplexer based on Fiber Bragg Grating（FBG） is designed for this system.The simulation results in data transmissions not only verify the feasibility of the proposed method,but also show that the system is well resistant to interchannel crosstalk.关键词：DWDM;ROF system;FBG;frequency interleaving;spectral efficiency
- 3
- |
- 98
- |
- 2
发布时间： - 摘要：In this paper,the effects of the structural parameters and scaling coefficients of photonic crystal fibers on the waveguide dispersion and lumped dispersion are analyzed in depth by using fully vectorial effective index method.The adjustment methods for the photonic crystal fiber dispersion characteristics are summarized,the design method for photonic crystal fibers with specific dispersion characteristics investigated and a photonic crystal fiber with nearly zero flattened dispersion at 800 nm wavelength designed.This fiber is valuable to the study of the propagation properties and applications of femtosecond lasers.关键词：photonic crystal fiber;dispersion control;fully vectorial effective index method;femtosecond laser
- 2
- |
- 143
- |
- 2
发布时间： - 摘要：This paper analyzes the causes of the generation of a central dip in the refractive index in fiber fabrication,sets up a model of the Graded-Index Fiber（GIF） with such a central dip and obtains the expressions for the time delay and self-focusing period of light transmissions by using the ray optics method.Simulation results show that with the increase of the dip width and depth,the self-focusing effects of the light beams in GIF become worse and the time delay difference increases.关键词：fiber optics;dispersion characteristics;ray optical method;multimode fiber;central dip
- 3
- |
- 77
- |
- 2
发布时间： - 摘要：As an important component in all-optical packet switching networks,the all-optical buffer has become a current focal point of research.This paper introduces the advances in the research on multiple types of all-optical buffers in recent years,including slow light,fiber delay line and fiber loop and summarizes their working principles,advantages and disadvantages and proposes a novel buffer based on complex modulation long-period fiber grating,which has the advantages of simple structure and low cost.关键词：all-optical buffer;Dual-Loop Optical Buffer（DLOB）;long period grating;complex modulation
- 3
- |
- 215
- |
- 10
发布时间： - 摘要：With the sustained growth of the demands for high-rate mobile communications,green communication becomes the current focus of research.This paper proposes a fiber-millimeter-wave convergence access system by using the harmonic generation technology in coordination with the ROF technology.This system provides access services to the indoor mobile terminals by using the pico-cell access networks.On this basis,it analyzes the energy efficiency of this system and compares it with that by WLAN access,which shows that this system has higher data rate and energy efficiency.关键词：fiber-millimeter-wave convergence;energy efficiency;millimeter-wave;access network
- 4
- |
- 40
- |
- 0
发布时间： - 摘要：This paper presents a novel Radio-over-Fiber（ROF） system scheme for carrying services with different transmission rates in a single channel.Double sideband modulation is realized by using external modulators and the sidebands and carrier are separated by grating filters.The two sidebands carry two kinds of services with different rates of 1.25 and 1.5 Gbit/s respectively in intensity modulation.Simulation results show that the system performances are good after the signals are transmitted for 50 km in an optical fiber.This scheme can improve the bandwidth utilization ratio of single channels and enhance the system flexibility.关键词：radio-over-fiber system;external modulation;multi-service
- 2
- |
- 65
- |
- 0
发布时间： - 摘要：On the basis of the TD-LTE system,this paper describes the basic concept of Error Vector Magnitude（EVM）,analyzes the factors affecting EVM and studies the EVM measurement algorithm for the system UE.Furthermore,it corrects the measured modulation symbols by the channel characteristics,presents the DSP realization method for the Physical Uplink Shared Channel（PUSCH） EVM measurement and performs MATLAB simulation,providing a theoretical basis for the improvement of the system functions.关键词：TD-LTE;EVM;measurement;DSP
- 3
- |
- 246
- |
- 19
发布时间： -
- Postal code：430205
- Technical support is provided by Beijing Founder electronics co., LTD 鄂ICP备2022010197
鄂公网安备 42011202002092号 - It is recommended to read the content of this site in Chrome&IE9+. Please switch to extreme mode in browser 360.
- Cookies We use cookies to help provide and enhance our service and tailor content. By continuing, you agree to the use of cookies.
- Total Visits：75845
0