最新刊期
卷 ， 期 4 ， 2008
- 摘要：In this paper,the properties of High Nonlinear Photonic Crystal Fibers（HN-PCF） and the basic principle for their generation are introduced,the mechanism for the generation of supercotinuum spectrum and slow light effects occurring in HN-PCF and its applications analyzed and the results of supercontinuum spectrum and slow light effect tests performed in China are given,in which the HN-PCF developed by the authors are used.关键词：High Nonlinear Photonic Crystal Fiber（HN-PCF）;supercontinuum;slow light effects
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- 545
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发布时间： - 摘要：This paper makes comparisons between the modified optical duobinary return-to-zero（MD-RZ） format and the optical duobinary non return-to-zero（MD-NRZ） format,which are both used in long distance transmission systems.Simulation results show that MD-RZ signals have lower BER and higher receiver sensibility than MD-NRZ signals by using the dispersion compensation technology.In addition,it presents a nove1 all-optical method for the generation of MD-RZ signals by using a Polarization Maintaining Fiber Loop Mirror（PMFLM） and theoretically proves its feasibility.关键词：fiber-optic communication;optical duobinary signal;MD-NRZ format;MD-RZ format;PMLPM
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- 155
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发布时间： - 摘要：In order to avoid inaccuracies in the pre-configured P-cycle protection resource allocation arising from the variations of the traffic distribution in WDM networks,a reconfigured P-cycle concept is proposed and a reconfigured P-cycle model based on network performance parameters set up.A simulation platform is constructed in OPNET to verify its efficiency on the basis of Pan-European COST239 network topology.Simulation results show that re-computing the optimized P-cycle according to the network variation can reduce the network performance jittering and improve the utilization rate of the protection resource.关键词：reconfigured P-cycle;WDM;protection;optical network
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发布时间： - 摘要：In view of the requirements for service growth,this article discusses in detail the advantages of ROADM device,presents a realization scheme for Wavelength Blocker（WB）-based ROADM and measures the maximum OSNR penalty of this ROADM node device in relation to its practical applications.The results indicate that this device meets the requirements in applications.关键词：ROADM;DWDM;OSNR penalty
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- 111
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发布时间： - 摘要：As a subnet of transport network management in TMN,Optical fiber cable line Automatic Monitoring System（OAMS） plays an important role in the stable operations of communication networks.This paper analyzes the deficiencies of the conventional OAMS and presents a scheme for its implementation in the conventional integrated network management systems for transport networks and designs the northbound interface for remote monitoring units.关键词：CORBA;OAMS;northbound interface;OTDR
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发布时间： - 摘要：Jitter is an important factor that can affect the quality of optical communication.In this article,four kinds of ODUk clocks in Optical Transport Networks（OTN） are first briefly introduced.Then,the requirements for their output jitters,jitter tolerances and jitter transfer functions specified in ITU-T recommendations are presented and the jitter of demapper clock（ODCp） analyzed.Finally,an example of the asynchronous demapper and the jitter measurement results are given.关键词：OTN;ODUk clock;jitter;phase error
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- 106
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- 1
发布时间： - 摘要：This article first explains the overall packet architecture of the Packet Transmission Network（PTN） that satisfies the requirement arising from the change in the service transmission mode from circuit-based TDM to packet-based IP or others.It then gives the layered architecture of T-MPLS packet transmission networks.Finally,it analyses the integrated bearing mechanism for TDM and IP services based on this architecture.关键词：PTN;T-MPLS;layered architecture
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- 179
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发布时间： - 摘要：This paper focuses on the hardware implementation of AES algorithms at low master frequency.On the basis of the characteristics of AES algorithms and the specific principle of hardware implementation,it brings forward a hardware implementation method for AES algorithms,by which considerations are given to both encryption speed and low clock frequency by using the strategy of implementing multiple encryptions in single clock period and the pipeline.Finally,it makes analysis of and comparison between this new method and the existing ones.关键词：key expansion;round transformation;pipeline
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- 90
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发布时间： - 摘要：In recent years,XML technology has found increasingly wider applications and there have been various ways of XML document parsing.This article introduces a scheme for the implementation of the DOM interface by using the standard C++ language with reference to the technical documents defined by W3C DOM Level 3 Core.After this scheme,the XML document can be parsed and the problem of low parsing speed that has been found in the commonly used XML parsers is avoided.关键词：XML;Document Object Model（DOM）;API
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- 281
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发布时间： - 摘要：As the only master management system,Network Management System（NMS） is the core of the entire communication network management,which will be disabled in case of failures,so warm backup switching technique is necessary.This article introduces an implementation model of the NMS warm backup,sets up its switching mechanism and places emphasis on the fault detection technique,which ensures the fast and accurate restoration of the communication network management in case of failures.关键词：warm backup;NMS;detection technique
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发布时间： - 摘要：A sample of single cladding highly Yb3+-doped silica optical fiber with high absorption and low background loss is fabricated by MCVD process with a new type of annular graphite heater furnace.Its geometric parameters and absorption spectrum are measured,analyzed and discussed,resulting in the conclusion that the key to this fabrication lies in depositing a high quality porous phosphosilicate layer（the soot layer） and that the P doing in the soot layer is helpful to the dopant solubility.Its absorption can be as high as 594 dB/m at 976 nm but its background loss is only 0.1 dB/m.
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- 124
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- 3
发布时间： - 摘要：By deducing the FWM efficiency of multi-section fiber-optic links,factors affecting the FWM efficiency of the full optical wavelength conversion are found out and the FWM efficiency fiber-optic links with any number of sections simulated by using Matlab.Take a 7-section fiber-optic link as an example.By adjusting the values of various parameters affecting the hybrid frequency efficiency,the optimum scope of its parameters is obtained,leading to a stable wavelength conversion efficiency.关键词：Four-Wave Mixing（FWM）;parametric process;FWM efficiency;multi-section fiber-optic link
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- 65
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发布时间： - 摘要：In order to reduce the effects of the ambient temperature variations on the resonant wavelength of the Long-Period Fiber Grating（LPFG） devices in communications,a scheme for the compensation of its drift is designed,i.e.coating the grating with a thin film whose refractive index increases with the rising temperature.The calculation results show that this scheme is feasible and will find extensive applications in communications as there will be no drift in the resonate wavelength.关键词：LPFG;resonant wavelength;temperature sensitivity
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发布时间： - 摘要：The Raman gain coefficient is a basic parameter for describing the Raman scattering.The coefficient is usually measured by small signal gain method,for which signal light is necessary.However,the measurement process is long and the measurement result is apt to be affected by unsteady pump light and signal light.In this paper,we put forward a new measurement,i.e.the Raman gain coefficient of optical fibers is obtained by the demodulation of the stimulated Raman spectrum and the spontaneous emission spectrum.The gain coefficient of the conventional G.652 Single Mode Fiber（SMF） is measured and the measurement result is compared with that by the small signal gain method.关键词：stimulated Raman scattering;Raman amplifier;Raman gain coefficient
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- 289
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发布时间： - 摘要：A design method for fused-cone lensed fibers is presented in this paper.Compared with the commonly used cone PM monomode fiber,its coupling efficiency with the Super-Luminescent Emitting Diode（SLED） chip increases from the original 45% to 60%,the working distance from 7 μm to over 15 μm and its coupling tolerance is far bigger than the latter.In addition,for this newly designed lensed fiber,the graph of coupling efficiency vs.offset and eccentricity is given.关键词：SLED;fused-cone lensed fiber;fiber coupling;coupling tolerance
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- 168
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发布时间： - 摘要：We first briefly introduce the commonly used calculation and analysis methods for Polarization-Dependent Losses（PDL） and conduct the analysis and calculation of the PDL of optical devices by using the Polarization Analysis function of ZEMAX.Then we compare the measurement results of the practical devices with the computed results by using the commonly used mathematic software,which prove the feasibility and accuracy of this method and show that it is possible not only to improve the designers’ working efficiency,but also to obtain accurate calculation and analysis results by using ZEMAX.关键词：PDL;ZEMAX;polarization analysis;Mueller matrix
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- 459
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发布时间： - 摘要：On the basis of short response time of grating light valve and high diffraction efficiency of reflection grating,a 1×3 micro optical switch using grating light valve is designed.Theoretical calculations and experimental results indicate that when the optical wavelength is 1.3 μm and the blaze angle and incident angle are 5.4 ° and 0 ° respectively,the switching time is on the level of microsecond.Compared with other similar optical switches,it has the advantages of short switching time,high diffraction efficiency and low operating voltage.关键词：grating light valve;optical switch;MEMS;diffraction angle
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- 106
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发布时间： - 摘要：The composition and operating principle of the 980 nm LD-FBG multiple optical cavity subassembly are introduced,its spectrum test results under different driving currents and ambient temperatures reported and the effects of the reflectivity of the wedge-shaped coupled fiber on its spectrum,the wavelength locking and the optimization of its structure analyzed and discussed.The test results indicate that the peak value of the optimized subassembly changes by <0.6 nm and the SMSR is >45 dB under the optical power of 100250 mW and at the ambient temperature of 2575 ℃.关键词：980 nm LD;FBG;multiple optical cavity subassembly;equivalent reflectivity;peak value wavelength locking
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发布时间： - 摘要：In this paper,a novel electro-optic modulator based on free space coupling technology is proposed.Incident light is directly projected upon the upper metal film surface that is used as the coupling layer.The amount of the energy that is coupled into the layer is controlled by altering the externally applied electrical field intensity so as to change the reflected light intensity,thus realizing electro-optic modulation.The modulator is characteristic of low insert loss,high response speed,high stability and low cost.Compared with the conventional polymer electro-optic modulator using prism coupling technique,the novel modulator is more compact and easier to be integrated.关键词：electro-optic modulator;electro-optic effect;metal-gladding waveguide;free space coupling
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发布时间： - 摘要：In the existing authentication schemes,SIP messages are liable to multiple security hazards,such as attacks by abnormal messages,network data interceptions and analysis of ciphertexts.After comparisons,analysis and improvement,an improved authentication scheme is designed,in which a parallel multi-process Tomita algorithm is used,SIP authentication header fields extended and ciphertext steganography system introduced,thus effectively ensuring the security of the application layer.Its effectiveness is verified by experimental results.关键词：SIP security;detection;authentication;ciphertext steganography
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发布时间： - 摘要：MBOK modulation is introduced in the UWB baseband system,for which no substantial bandwidth increase is necessary when the data transmission rate is to be boosted.In order to improve the data transmission reliability,a block interleaver is added before the data coding.What is unique to this design is that two pieces of RAM registers are employed for alternative reading and writing so as to minimize the time delay of the interleaver.Besides,programming is implemented with VHDL and simulations performed on FPGA with QUARTUS II.The result shows that when the interleaver is added to the MBOK system,burst errors are interleaved for easier error corrections of the system.关键词：MBOK modulation;FPGA;block interleaver
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发布时间： - 摘要：This paper describes in detail the manufacturing process of and budget for a specially structured 3 dB hybrid,and presents a design scheme for the approximately stripline-structured 3 dB hybrid so as to make it better directional and easier to manufacture.It operates from 800 MHz to 2 500 MHz and supports fairly large power capacity.Thanks to its new structure,it has smaller volume,lower insertion loss,higher directionality and broader bandwidth,and is easier to manufacture and test.关键词：3 dB hybrid;bandwidth;tight coupling
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