最新刊期
卷 ， 期 3 ， 2006
- 摘要：Transport MPLS（T-MPLS） hierarchy（TMH） is the key point in recent transport network technology study.MPLS is the important solution for IP technology and increase of QoS.Current transport network is still TDM based（e.g.SDH） optical transport network.How to transport MPLS client in exist transport network,every one is taking care.Since the requirements of network interconnection or interwork,the uniform specification of interfaces is necessary.The specification of TMH interfaces were introduced in this paper,include location of TMH interface,NNI basic signal structure,information structure for T-MPLS NNI,T-MPLS labels,multiplexing and mapping principles and physical specification of the T-MPLS interfaces etc.关键词：MPLS;transport network;T-MPLS;TMH;NNI
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- 157
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- 3
发布时间： -
- 摘要：Automatic Switched Optical Network（ASON） is a highly flexible and extensible infrastructural network,which can provide services directly at the optical layer to rapidly satisfy the subscriber requirements thanks to its advantages in extensibility,manageability,subscriber bandwidth distribution and end-to-end network protection.Proposed in this paper is the architecture of ASON,which consists of three planes,three kinds of interfaces and three types of connections.关键词：ASON;Permanent Connection（PC）;Switched Connection（SC）;Soft Permanent Connection（SPC）
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- 150
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- 16
发布时间： - 摘要：Protection-switching time is an important measure for evaluating the performance of a network protection scheme.In this article,a protection-switching model for multicast connections in WDM network is presented,on which basis the protection-switching time of the main multicast protection schemes,including link-disjoint,arc-disjoint and segment protection, is analyzed and compared.The overall performances of these schemes are briefly assessed in connection with the blocking probability.关键词：WDM;multicast;protection-switching
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- 50
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- 2
发布时间： - 摘要：One of the important design issues for the large-scale global conferencing system is to enhance the scalability of the conference management architecture.In this paper,the design of the SIP-based distributed management architecture for large-scale conferencing services is introduced and a new approach is presented to overcome the scalability problems in multimedia conferencing by taking advantage of the policy-based management technology.关键词：multimedia conference;distributed management;SIP;policy-based management
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- 98
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- 3
发布时间： - 摘要：A low-jitter PLL CDR circuit for fiber-optic communications is introduced,which adopts a second-order active LP filter using negative-impedance amplification and forms a VCO with PECL ring time-delay elements,operating within the range of 80～500 MHz with the peak-peak jitter <20 ps and the phase-lock time <600 ns.Both pre-and post-layout simulations of the actual circuit prove to be successful.关键词：CDR;low-pass filter;PLL;NZR
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- 268
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发布时间： - 摘要：The continuously increasing need for network supervisory information and additional services can be better met by adopting 25.344 Mbit/s optical supervisory information transport technology.This paper starts with an introduction to its technological scheme,then continues with a detailed description of its frame structure,code pattern design and the hardware implementation block diagrams and ends with a presentation of its advantages.关键词：optical supervisory channel;WDM;network management channel（NMC）
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- 47
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发布时间： - 摘要：The characteristics of FiberHome network management system and its upgrade and improvements to meet Liaoning Mobile’s needs are briefly described and the future development of integrated transmission network management systems discussed and forecasted on the basis of the authors’ participations in the software upgrade and verification test of FiberHome OTNM2000.Furthermore,such functions that the future integrated transmission network management system should have as network monitoring,resource management,resource distribution,customer management,network analysis and system support are illustrated in detail.关键词：OTNM2000;transmission network management system;subnet management;traffic management
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- 47
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- 1
发布时间： - 摘要：The authentication technique of the access network has supported the growth of the broadband access networks.At the present,there are three types of the most widely used authentication techniques,i.e.PPPoE,Web and 802.1x.In this paper,a primary model of the user authentication system is presented,on which basis the above authentication techniques are analyzed and compared.In consideration of extensibility,Web is the best and will have better chance of development.关键词：broadband access network;user authentication;PPPoE;Web;802.1x
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- 214
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- 24
发布时间： -
- 摘要：The article begins with a brief discussion on the present status of local SDH transmission networks,which is followed by fairly detailed descriptions of the hierarchical and ring network structures,the computations of the regenerative sections in equipment allocations,network synchronization and the conditions for their applications.Then practical SDH networking is analyzed and the development and planning of the local SDH transmission networks are expounded.It is ended with an emphasis of the importance of transmission network planning in telecom network construction.关键词：SDH;network planning;self-healing-ring;line rate;regenerative section;Protection switching;survivability
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- 179
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- 10
发布时间： - 摘要：As WDM systems have been widely used,the maintenance of the WDM equipment has become very important.Based on his experience in practice,the author has summarized the main points in the maintenance of different parts of the equipment and recommended the commonly used failure recovery methods.关键词：WDM;operating maintenance;failure;location
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- 44
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- 0
发布时间： - 摘要：Optical Internet is the next generation Internet that can meet the demand for high bandwidth and the study of its interconnection models is a hot spot in the current research.In this article,the basic trend that the peer model will take the place of the overlay model is analyzed and an intermediate model,i.e.hybrid model is presented on the basis of the comparison of the inherent three interconnection models,i.e.the peer model,overlay model and augmented model,which can support the coexistence of the peer model and the overlay model.The principle and mechanism for the realization of the hybrid model is highlighted.关键词：optical Internet;interconnection model;peer model;overlay model;hybrid model
- 2
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- 71
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- 1
发布时间： - 摘要：Analytical comparison has been made between two optical hard-limiters method and multibits transmission method for the suppression of interference to the optical CDMA multiusers.The derivation and simulation of their BER performances shows that the former is 5 orders of magnitude better when the received power is larger than-52 dBm.关键词：fiber-optic communication;CDMA;multiuser interference;hard-limiter
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- 96
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- 1
发布时间： - 摘要：As laser gain dielectrics,rare-earth doped fibers have been extensively applied in fiber-optic communications,lasers,amplifiers and sensors.In this paper,the properties of Erbium-doped and Ytterbium-doped fibers are introduced and the current researches therein and the trend of the development highlighted,which shows that remarkable progress has been made in their development in China.关键词：Erbium-Doped Fiber（EDF）;Ytterbium-doped fiber;fiber amplifier;fiber laser
- 3
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- 404
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- 15
发布时间： - 摘要：The dispersion characteristics of Photonic Crystal Fibers（PCF） are studied by the vector effective index method,with the emphasis on the analysis of the effect of its structural parameters on its dispersion properties.Three design schemes for the PCF structural parameters are proposed,which are valuable for accelerating the application of PCF in fiber-optic communication systems.关键词：photonic crystal fiber;effective index model;chromatic dispersion
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- 348
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- 3
发布时间： - 摘要：Optical heterodyne technology is widely used in radio over fiber system in generating millimeter waves because of its low price and simple structure,but center stations generally use coherent source to eliminate phase noise.In this paper,a modified optical heterodyne method is proposed and system analysis and simulation experiments show that its adoption will relieve the center station of the need to use coherent source and both the center station and radio terminals of the need for local millimeter wave oscillation.Furthermore,using single band modulation in center stations will effectively reduce the fiber dispersion effect.关键词：optical communication;radio over fiber;optical heterodyne;single band modulation;fiber dispersion
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- 300
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- 1
发布时间： - 摘要：Theoretical analysis and experimental research have been carried out for the fiber-optic coupling of the 40 Gbit/s PIN/TIA module,which has been fixed in UV gel and fine curing method,bringing its sensibility to the leading level in China.The tests show that its optical responsivity can be up to 0.65 A/W after fine fiber collimation and over 0.46 A/W after coupling curing.关键词：optical coupling;Gaussian beam;coniform optical fiber;cuneiform optical fiber;optical responsivity;UV adhesive
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- 138
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- 1
发布时间： - 摘要：Theoretical analysis has been made of several kinds of Raman pump laser depolarization based on Jones matrix and Stock parameters and the numerical computation of the depolarization degrees of the actual laser spectrums performed.When the Polarization Beam Combined（PBC） method is adopted,the minimum Degree Of Polarization（DOP） can be obtained only when the optical powers of the two lasers are identical.However,when PBC plus the birefringent crystal depolarization are adopted,the DOP after PBC is always smaller with the variations of the crystal length than that when a single laser runs through the crystal.Therefore,the crystal length should be so designed as required by single laser depolarization to maintain the DOP with different pump sources.The design method and conclusion presented in this paper may contribute to the depolarization design for the pump laser of Raman amplifiers.关键词：Jones matrix;Stocks parameter;Raman amplifier;DOP
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- 82
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- 2
发布时间： - 摘要：The diffraction characteristics of the phase mask for fiber grating fabrication is investigated using rigorous coupled-wave theory.The results show that in order to keep the zero order diffraction efficiency <5% and ±1st order diffraction efficiency >35% at UV-written wavelength of 248 nm,the groove depth and duty cycle of the mask must be controlled within the range of 230280 nm and 0.480.65 respectively.This conclusion has been analyzed and compared with that based on scalar diffraction theory.Useful information has been resulted for the practical fabrication of the phase mask.关键词：phase mask;optical fiber grating;diffraction efficiency;rigorous coupled-wave theory
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- 272
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- 6
发布时间： - 摘要：3-D optical beam splitters effectively increase the density of integrity and channel number and overcome some of the input/output problems in 2-D integrated optics while preserving the reliability and structural stability of the latter.This paper presents an overview of the advances in the research in 3-D integrated optical beam splitters,a detailed introduction to their existing structures and technological schemes and the comparisons of their performances and concludes with prospects for their applications.关键词：3-D integrated optics;optical beam splitters;multimode interference couplers
- 2
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- 201
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发布时间： - 摘要：As key passive devices in WDM networks,integrated acoustooptic devices can help realize such functions as switching,filtering and modulation.They have become the focal point of the research for their characteristics of high speed,wide bandwidth and the capability of simultaneous multi-wavelength operation.The existent integrated acoustooptic devices are classified and the operating principle and development of waveguide integrated acoustooptic devices described and the merits and demerits of two much-researched types compared.In addition,the key technical problems to be solved at present are pointed out and the trend of their development anticipated.关键词：optical integrated devices;acoustooptic interaction;mode conversion;Bragg diffraction;acoustic surface wave
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- 206
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发布时间： - 摘要：When the temperature or stress on the Fiber Bragg Grating（FBG） sensor is changed,the Bragg wavelength will shift accordingly. The measurand can be assessed by detecting the shift.Many signal demodulation methods for detecting the shift of the FBG sensor have been proposed.In this paper,several commonly used ones are described,their operating principles and performances reviewed,their typical experimental schematic diagrams given and their merits and demerits analyzed and compared.关键词：Fiber Bragg Grating（FBG）;demodulation;sensing;review
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