最新刊期
卷 ， 期 3 ， 2012
- 摘要：For the expansion of the linear dynamic range of Radio over Fiber（ROF） communication systems,this paper summarizes the advances in the relevant study in China and abroad and sorts out and expounds the constraints on the system dynamic range.It focuses on a dispersion-immunized highly linear modulation technology,which is based on the dual parallel Mach-Zehnder modulator structure and pre-distortion idea.Experiments verify the correctness of the principle and the optimum experimental conditions and prove that the new technology improves the dynamic range measuring value of ROF communication systems by at least 20 dB over conventional ROF systems in 25 km single-mode fiber transmission.关键词：optical communication;ROF;signal damage compensation;linear dynamic range
- 2
- |
- 121
- |
- 3
发布时间： - 摘要：An improved Artificial Fish Swarm Algorithm（AFSA） is applied for the first time to multi-channel Polarization Mode Dispersion（PMD） compensation in Wavelength-Division-Multiplexing（WDM） systems.In this paper,a compensation scheme used in multi-channel PMD compensation is first discussed and then this algorithm is briefly introduced and the detailed steps of its use given.Finally,its effectiveness is verified in a 6×40 Gbit/s RZ-coded PMD compensation system.The simulation results show that the every compensated channel can reach over 0.95 degrees of polarization and the opening of the eye diagram increases after compensation and the algorithm has a good compensation effect.关键词：PMD compensation;AFSA;WDM system
- 3
- |
- 42
- |
- 0
发布时间： - 摘要：Adaptive dispersion compensation is one of the core technologies of ultrahigh rate fiber-optic communication networks and dynamic on-line monitoring on optical signal dispersion is the key to adaptive dispersion compensation.In this paper,we systematically review the study on dispersion monitoring technologies and its present status of development and analyze and compare their mechanisms,features and implementations.Above all,we put emphasis on introducing the all-optical and digital coherent detection-based dispersion monitoring technologies and discuss the tendency of their future development.关键词：dispersion;fiber-optic communication;all-optical dispersion monitoring;digital coherent detection
- 3
- |
- 132
- |
- 3
发布时间： - 摘要：The TR-101 system architecture standard describes the transition of the ATM-based converging network to a new Ethernet-based converging network and defines a new access network topology.This proposition provides a technological guidance for the deployment of EPON technology.This paper mainly discusses a number of important issues in EPON applications,such as VLAN functions,multicast functions,OAM and network management.关键词：TR-101 system architecture;EPON;VLAN;multicast
- 3
- |
- 21
- |
- 0
发布时间： - 摘要：At present,the head compression technology mostly refers to high layer head compression.As a matter of fact,head compression in layer two can gain considerable transmission bandwidth with a minimum overhead.In view of the distribution and features of data transmission in communication systems,this paper proposes an MAC/IP joint head compression algorithm appropriate for Point-to-Multipoint（P2MP） communication architecture and gives a concrete module design scheme for and realization of such a compression on the basis of this algorithm.关键词：P2MP communication system;MAC/IP joint head compression;PPPoE map;ARP
- 2
- |
- 59
- |
- 4
发布时间： - 摘要：The Selective Mapping（SLM） algorithm can solve the problem of high Peak-to-Average Power Ratio（PAPR） in Orthogonal Frequency Division Multiplexing（OFDM） systems,but the basic SLM algorithm has high computational complexity.This paper presents a so-called Grouping SLM（G-SLM）,which can reduce computational complexity as a result of the combination of the input signals with phase factor by grouping the former.Simulation results show that this algorithm can not only have fairly low computational complexity,but also effectively reduce the PAPR.关键词：OFDM;PAPR;grouping;SLM
- 2
- |
- 96
- |
- 3
发布时间： - 摘要：In order to increase the time delay of Brillouin slow light and decrease its pulse broadening,fiber-based Stimulated Brillouin Scattering（SBS） coupled equations are numerically solved by using the upwind scheme-based finite difference method and,when continuous light with slowly changing rising edge is used as the pump light,the changes of the time delay and pulse broadening factors of Stokes light at the fiber output end with gain are analyzed.Numerical results indicate that such a pump light can increase the time delay of long Gaussian pulses（FWHM=120 ns） up to 52 ns and that of short Gaussian pulses（FWHM=20 ns） up to 64 ns and at the same time reduce the pulse broadening of long and short Gaussian pulses.关键词：optics;SBS;slow light;time delay
- 2
- |
- 38
- |
- 0
发布时间： - 摘要：In order to analyze the end-to-end delay performance of aggregate traffic in converged networks,this paper proposes a new algorithm for the end-to-end statistical delay bound of aggregate flow-based converged networks.Using the theorem of the Moment Generating Function（MGF）,this algorithm re-characterizes the MGF probabilistic model of network end-to-end delay bound.Numerical analysis results show that this algorithm is effective and can improve independent statistical multiplexing to a great extent,offering much value of reference for converged network performance evaluation.关键词：aggregate traffic;converged network;statistical network calculus;MGF
- 2
- |
- 55
- |
- 2
发布时间： - 摘要：Optical communication modules for intelligent electric energy meters play an important role in the construction of smart grids.On the basis of the comparisons between and analysis of EPON,PLC,WiMAX technologies,EPON is selected as the communication access network technology for intelligent electric energy meters and the communication flow is designed.On the basis of QCA8829 embedded chips and the fiber-optic interface technology accessible to the EPON systems on the Redhat Linux 2.6.x development platform,the communication system from the master station to the slave station of intelligent energy meters is realized.Test results show that the proposed modules accomplish complete collection and full coverage of information at power distribution side of the smart grids and enable remote cost control and load control to the home.关键词：EPON;DL/T645-2007 protocol;Q/GDW376.1-2009 protocol;intelligent energy meter;embedded
- 2
- |
- 109
- |
- 5
发布时间： - 摘要：On the basis of optical network geographical distribution model,we simulate the network topological structure by using the worst line cut algorithm and find out the worst line cut aggregation and the link risk probability of the network,In addition,we assess the network safety on the basis of the link risk probability.This work has a certain value of reference for improving optical network survivability.关键词：optical network geographiccal distribution;worst line cut;link risk probability
- 3
- |
- 31
- |
- 4
发布时间： - 摘要：To develop a practical portable embedded OTDR,this paper presents and implements a design scheme,in which Field Programmable Gates Array（FPGA） is adopted for data acquisition,accumulation and averaging and ARM for human-computer interaction and data analysis.It briefly introduces the system working principle and hardware and software design,with emphasis on the FPGA procedures.The experimental results show that this design converges the characteristics and advantages of above two chips and enormously improves the system performance.关键词：OTDR;FPGA;ARM
- 2
- |
- 129
- |
- 2
发布时间： - 摘要：Sensors are the core of the Internet of Things（IOT） and fiber-optic sensors have incomparable superiorities over electric ones.On the basis of their fundamental principles and status of development,this paper designs an IOT-based application scheme for the fiber-optic sensing technology in line with its development and different application scenarios.This scheme satisfies the needs of different industries and promotes their intelligentization.关键词：IOT;fiber-optic sensing technology;RFID technology
- 11
- |
- 443
- |
- 18
发布时间： - 摘要：In order to eliminate blind spots in optical cable mechanical property monitoring and prevent hidden failures due to mechanical performance degradation,we study the theory of fiber excess length in optical cables and the monitoring principles of BOTDA and OTDR.Using the BOTDA monitoring technology,we conduct monitoring experiments for the fiber strain in the cables.In combination with theoretical analysis,we obtain the relationship of fiber strain changes with the cable stress,strain and mechanical properties,which can act as a prewarning for the potential mechanical property deterioration of optical cables.关键词：BOTDA;OTDR;stress-strain;optical fiber cable;monitoring
- 3
- |
- 148
- |
- 6
发布时间： - 摘要：In view of such disadvantages as high material loss,complexity of preparation processes,and poor transmission performances and output beam qualities in ordinary infrared fibers,a new type of large core infrared Photonic Band Gap Photonic Crystal Fiber（PBG-PCF） is presented,which is appropriate for CO2 laser transmission.The large core of such a fiber is produced by removing 19 capillary air holes from the center of photonic crystals with triangular lattice.A fiber bandgap figure of CO2 laser at a transmission wavelength of 10.6 μm is first obtained by PWM analysis and then,its loss characteristics are analyzed by using the simulation software COMSOL Multiphysics based on the full vector finite element method.The results show that the new photonic crystal fiber has smaller loss,about 0.08dB/km,in 10.6 μm CO2 laser transmission than the existing infrared fibers,satisfying the needs of high power CO2 laser transmissions for medical applications.关键词：CO2 laser transmission;large core;PBG-PCF;PWM;FEM
- 2
- |
- 163
- |
- 2
发布时间： - 摘要：In this paper,we study the dispersion,loss,effective mode field area and nonlinearity of the hybrid Photonic Crystal Fibers（PCF） by using the finite element numerical analysis method.Simulation results show that its confinement loss is reduced to the magnitude of 10-6 dB/m in the range of 0.62.0 μm,satisfying the requirements for double-zero dispersion point.In addition,its effective mode field area reaches 755 μm2 in the long wavelength range,and nonlinear coefficient is 1.039×10-4 m-1W-1,appropriate for being used as the gain media of high-power narrow-linewidth fiber lasers.关键词：hybrid PCF;dispersion;confinement loss;effective mode field area;nonlinear coefficient
- 2
- |
- 58
- |
- 1
发布时间： - 摘要：Using the full-vector finite element method,we study the birefringence properties of a rectangular lattice Photonic Crystal Fiber（PCF） with a central elliptical defect hole in the core region.The research results show that its birefringence properties are strongly dependent on wavelength and its structural parameters.Compared with similar PCF without central elliptical defect holes,the new PCF has a higher modal birefringence when the central elliptical defect hole parameters bc/Λ=0.075,ellipticity η=2.2 and cladding structural parameters Λ=2.0 μm,d/Λ=0.48.关键词：fiber optics;photonic crystal fiber;birefringence
- 2
- |
- 50
- |
- 3
发布时间： - 摘要：A new microstructured optical fiber with composite square air-hole lattice is presented,the cladding of which is composed of air holes of different sizes.The effects of the changes of its geometric structural parameters on the dispersion curves of the fundamental mode are analyzed by using the Finite-Difference Time-Domain（FDTD）method.The results show that with two sets of air holes,this microstructured fiber has strong dispersion control capability and relatively lower and more flattened dispersion curves by optimization.关键词：microstructured optical fiber;FDTD method;dispersion
- 2
- |
- 53
- |
- 0
发布时间： - 摘要：Home-entry optical fiber cable lines are the key parts in FTTH system construction.But currently we lack the experiences in their construction,operation,maintenance and management.Starting from their composition,we analyze the performances of their commonly used equipment and present their installation requirements and the relevant equipment selection principles on the basis of their engineering practice,which can be used as important reference for their design and construction.关键词：FTTH;BOW-type optical cable;design;construction
- 2
- |
- 148
- |
- 22
发布时间： - 摘要：For the purpose of realizing the optical channel monitoring in WDM systems with 50 GHz channel intervals,we present a design of diffractive grating-based Optical Channel Monitor（OCM） and introduce its working principle.Then we calculate and analyze its insertion loss,working range,response time,wavelength and channel resolutions and conduct experimental tests on the sample.The results show that this OCM module can accurately monitor the channel wavelength and power performance of the WDM systems at 50 GHz intervals and with hybrid transmission rates of 10 Gbit/s/40 Gbit/s.关键词：DWDM;optical channel monitor;channel interval;hybrid transmission system
- 2
- |
- 55
- |
- 0
发布时间： - 摘要：Moiré grating-based two-wavelength self-seeding of dc biased Fabry-Perot laser diode is presented to obtain an experimental scheme for beat frequency signals.Dual-wavelength self-seeding can be experimentally obtained with the Side Mode Suppression Ratio（SMSR） close to or higher than 30 dB over the wavelength range of 11.7nm,generating beat frequency signals at as high as 168 GHz.This millimeter-wave system is characteristic of simple structure and low cost.关键词：Moiré grating;self-seeding;dual-wavelength;millimeter-wave;SMSR
- 2
- |
- 42
- |
- 1
发布时间： - 摘要：Practical L-band Erbium-Doped Fiber Amplifiers（EDFA） often adopt multi-stage Erbium-doped fiber and multi-pump lasers.In this paper,the temperature characteristic of an L-band EDFA with such a complex configuration is experimentally investigated.It is found that the gain spectra of the short-wavelength（about 1 5701 582 nm） side of the L-band change with temperature in a reverse direction,which is theoretically explained.The experimental results show that there is still a good linear relationship between the Er-doped fiber temperature and the L-band EDFA gain tilt.Thus,the gain tilt of L-band EDFA can be adjusted by controlling the fiber temperature so as to achieve flattened gain.关键词：L-band;EDFA;gain-tilt;temperature
- 2
- |
- 61
- |
- 1
发布时间： - 摘要：An improved Y defect-based photonic crystal optical splitter is proposed so as to improve the transmittance of its output ports.Lead-in defects are introduced into the complete 2-D photonic crystal to form a 1×4 Y-type photonic crystal splitter.Each of the output ports is enabled to have a higher transmittance by regulating the radiuses of the four dielectric cylinders in the first branch,while flexible adjustment of the high transmittance and output optical energy at the output ports can be achieved by changing the radius of one dielectric cylinder in the second branch.It is concluded that such a splitter can be extensively applied in the fields of optical circuit integration,integrated optics,low-light level information processing and optical communications in the future.关键词：photonic crystal optical splitter;dielectric cylinder;transmittance;optical energy
- 3
- |
- 75
- |
- 3
发布时间： - 摘要：TD-LTE system services are asymmetrically offered and the requirement on downlink data rate exceeds that on uplink data rate.Therefore,more rigorous requirements are placed on the resource allocation of the system uplink and downlink channels.In this paper,intelligent dynamic resource allocation is performed for the system channel resources by using the outage probability-based call admission control algorithm.System simulation proves that the system time slot resources can be flexibly allocated by using this strategy.关键词：outage probability;admission control strategy;channel resource
- 2
- |
- 82
- |
- 1
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