无源光网络

本通过对信息技术发展、网络流量剧增形势的深入分析,得出了在电信网络朝数字化、宽带化方向发展的情况下,发展宽带接入技术,建立OAN（光纤接入网）是接入网发展的必然趋势的结论。然后,着重介绍宽带接入的首选技术——PON（无源光网络）系统的组成、工作原理及其存在的技术难点;介绍PON的组网能力及其杰出的可靠性;最后介绍利用PON构建宽带接入网的优势,及其与未来电信发展趋势相适应的前景。     

无源光网络

本文通过对信息技术发展、网络流量剧增形势的深入分析,得出了在电信网络朝数字化、宽带化方向发展的情况下,发展宽带接入技术,建立OAN(光纤接入网)是接入网发展的必然趋势的结论。然后,着重介绍宽带接入的首选技术———PON(无源光网络)系统的组成、工作原理及其存在的技术难点;介绍PON的组网能力及其杰出的可靠性;最后介绍利用PON构建宽带接入网的优势,及其与未来电信发展趋势相适应的前景。     

宽带综合业务接入网——数字化生活的基石

文章从通信网络的发展趋势出发,阐明了宽带接入网的发展方向和接入网目前常用的接入技术,论述了国内通信网尤其是接入网的宽带化和IP化的必然趋势及解决方案。     

无源光网络技术发展及应用

无源光网络（PON）是目前实现接入网宽带化的理想接入技术，文章探讨了PON技术的发展经过，并对EPON技术在当前的应用进行了分析预测。     

无源光纤接入网宽带PON网络设计方案优化

随着科学技术的迅猛发展,互联网技术的应用程度实现了质的飞跃,运用互联网技术进行办公和获取咨询的人越来越多,在这样的时代背景下,人们对于接入宽带的要求也在不断提高.本文对无源光纤网络技术进行系统的阐述,就SDH宽带接入、IP网络接入、层组网接入、基站互联以及光纤接入五个方面对无源光纤接入网宽带PON网络方案进行介绍,最后对如何进行方案优化提出建议,期望为无源光纤接入网宽带PON网络方案设计提供参考意见.     

宽带接入技术的探讨

当前,通信网络正在发生深刻的变化,各种数据、图像业务方兴未艾。高速上网、远程医疗、视频会议、VOD等各项业务应用愈来愈多,通信网络正在由窄带信息服务向多媒体宽带信息服务转移,通信网络的宽带化和IP化已成为必然趋势。为适应和满足当前形势的变化和发展,各地及运营企业都在大力建设IP宽带网络(或ATM网络),那么原先以传统话音和窄带业务为主的接入网如何改造和发展呢?如何建设一个数字化、宽带化、综合化的用户接入网是牵涉到整个宽带通信网络建设与使用的关键一环,是信息高速公路的“最后一公里”,也是“第一公里”。根据当前电信技术的应用与发展,这里介绍几种宽带接入技术,结合个人的观点进行分析与比较。     

无源光网络PON技术在宽带通信中的应用

随着网络技术的不断发展,网络宽带化已经成为下一代接入网的必然要求,新的数字业务的发展成为网络技术发展的必然。在网络接入方面,传统的XDSL宽带接入方式不能满足上述网络接入的需要,以光纤为传输介质的PON技术成为网络接入技术发展的重要趋势。推动了PON相关的EPON、GPON技术快速发展,并且己成为电信领域的热点技术。     

电信网的演进趋势和发展展望(上)

本文从网络业务应用和网络交换技术两方面讨论了向IP化和分组化的汇聚和演进,向分组化演进的路线,基础传送网的宽带化,MPLS技术的发展,核心网向光联网的发展,业务层核心网的宽带化,面临挑战的城域网,接入网的宽带化和IP化以及网络功能结构的扁平化趋势。     

信息产业部有线通信专业情报网第27届技术交流会征文通知

信息产业部有线通信专业情报网第 2 7届技术交流会主题拟定为“宽带综合接入系统”,现进行征文。主要内容如下 :1 .宽带综合接入网传送技术、实现方案的研究 ;2 .宽带综合接入设备的研究开发 ;3.A- PON技术、x DSL技术的研究及实现 ;4.HFC技术、Cable Modem技术的研究及实现 ;5.IP交换技术、宽带 IP接入网技术的研究 ;6.宽带综合接入网网管技术、测试技术的研究及实现 ;7.宽带多业务接入服务器的研究 ,宽带业务节点接口 VB5的研究 ;8.ATM和 IP结合技术的研究 ,三网融合方案的研究 ;9.高速路由器技术的研究与实现 ;1 0 .IP电话网关…     

宽带接入技术的探讨

<正> 当前,通信网络正在发生深刻的变化,各种数据、图像业务方兴未艾。高速上网、远程医疗、视频会议、VOD 等各项业务应用愈来愈多,通信网络正在由窄带信息服务向多媒体宽带信息服务转移,通信网络的宽带化和 IP 化已成为必然趋势。为适应和满足当前形势的变化和发展,各地及运营企业都在大力建设 IP 宽带网络(或 ATM 网络),那么原先以传统话音和窄带业务为主的接入网如何改造和发展呢?如何建设一个数字化、宽带化、综合化的用户接入网是牵涉到整个宽带通信网络建设与使用的关键一环,是信息高速公路的“最后一公里”,也是“第一公里”。根据当前电信技术的应用与发展,这里介绍几种宽带接入技术,结合个人的观点进行分析与比较。     

Resolution Enhancement Technology:Integrated Process Solutions using OPC

DUV lithography, using the 248 nm wavelength, is a viable manufacturing option for devices with features at 130 nm and less. Given the low kl value of the lithography, integrated process development is a necessary method for achieving acceptable process latitude. The application of assist features for rule based OPC requires the simultaneous optimization of the mask, illumination optics and the resist.Described in this paper are the details involved in optimizing each of these aspects for line and space imaging.A reference pitch is first chosen to determine how the optics will be set. The ideal sigma setting is determined by a simple geometrically derived expression. The inner and outer machine settings are determined, in turn,with the simulation of a figure of merit. The maximum value of the response surface of this FOM occurs at the optimal sigma settings. Experimental confirmation of this is shown in the paper.Assist features are used to modify the aerial image of the more isolated images on the mask. The effect that the diffraction of the scattering bars (SBs) has on the image intensity distribution is explained. Rules for determining the size and placement of SBs are also given.Resist is optimized for use with off-axis illumination and assist features. A general explanation of the material' s effect is discussed along with the affect on the through-pitch bias. The paper culminates with the showing of the lithographic results from the fully optimized system.     

Cost-effective test solutions for smart card and other integrated flash applications

From its emergence in the late 1980s as a lower cost alternative to early EEPROM technologies, flash memory has evolved to higher densities and speedsand rapidly growing acceptance in mobile applications.In the process, flash memory devices have placed increased test requirements on manufacturers. Today, as flash device test grows in importance in China, manufacturers face growing pressure for reduced cost-oftest, increased throughput and greater return on investment for test equipment. At the same time, the move to integrated flash packages for contactless smart card applications adds a significant further challenge to manufacturers seeking rapid, low-cost test.     

An improved parallel thinning algorithm with two subiterations

The parallel thinning algorithm with two subiterations is improved in this paper. By analyzing the notions of connected components and passes, a conclusion is drawn that the number of passes and the number of eight-connected components are equal. Then the expression of the number of eight-connected components is obtained which replaces the old one in the algorithm. And a reserving condition is proposed by experiments, which alleviates the excess deletion where a diagonal line and a beeline intersect. The experimental results demonstrate that the thinned curve is almost located in the middle of the original curve connectivelv with single pixel width and the processing speed is high.     

Theoretical analysis of the relationship between the Brillouin gain coefficient and the strain in the optical-fiber sensors

The relation between the power of the Brillouin signal and the strain is one of the bases of the distributed fiber sensors of temperature and strain. The coefficient of the Bfillouin gain can be changed by the temperature and the strain that will affect the power of the Brillouin scattering. The relation between the change of the Brillouin gain coefficient and the strain is thought to be linear by many researchers. However, it is not always linear based on the theoretical analysis and numerical simulation. Therefore, errors will be caused if the relation between the change of the Brillouin gain coefficient and the strain is regarded as to be linear approximately for measuring the temperature and the strain. For this reason, the influence of the parameters on the Brillouin gain coefficient is proposed through theoretical analysis and numerical simulation.     

Novel fiber-optical interferometer with miniaturized probe for in-hole measurements

Today, micro-system technology and the development of new MEMS （Micro-Electro-Mechanical Systems） are emerging rapidly. In order for this development to become a success in the long run, measurement systems have to ensure product quality. Most often, MEMS have to be tested by means of functionality or destructive tests. One reason for this is that there are no suitable systems or sensing probes available which can be used for the measurement of quasi inaccessible features like small holes or cavities. We present a measurement system that could be used for these kinds of measurements. The system combines a fiber optical, miniaturized sensing probe with low-coherence interferometry, so that absolute distance measurements with nanometer accuracy are possible.     

Study of waveguide coupling efficiency in hybrid silicon lasers

This paper presents a new method to increase the waveguide coupling efficiency in hybrid silicon lasers. We find that the propagation constant of the InGaAsP emitting layer can be equal to that of the Si resonant layer through improving the design size of the InP waveguide. The coupling power achieves 42% of the total power in the hybrid lasers when the thickness of the bonding layer is 100 nm. Our result is very close to 50% of the total power reported by Intel when the thickness of the thin bonding layer is less than 5 nm. Therefore, our invariable coupling power technique is simpler than Intel＇s.     

A rigorous proof of MIMO channel capacity’s increase with antenna number

It is well known that adding more antennas at the transmitter or at the receiver may offer larger channel capacity in the multiple-input multiple-output（MIMO） communication systems. In this letter, a simple proof is presented for the fact that the channel capacity increases with an increase in the number of receiving antennas. The proof is based on the famous capacity formula of Foschini and Gans with matrix theory.     

Teleportation of an arbitrary unknown N-qubit entangled state under the controlling of M controllers

A new quantum protocol to teleport an arbitrary unknown N-qubit entangled state from a sender to a fixed receiver under M controllers(M < N) is proposed. The quantum resources required are M non-maximally entangled Greenberger-Home-Zeilinger (GHZ) state and N-M non-maximally entangled Einstein-Podolsky-Rosen (EPR) pairs. The sender performs N generalized Bell-state measurements on the 2N particles. Controllers take M single-particle measurement along x-axis, and the receiver needs to introduce one auxiliary two-level particle to extract quantum information probabilistically with the fidelity unit if controllers cooperate with it.     

Diode-end-pumped Nd:YVO4/LBO lasers with 4.2W continuous-wave output at 457 nm

A continuous-wave (CW) 457 nm blue laser operating at the power of 4.2 W is demonstrated by using a fiber coupled laser diode module pumped Nd: YVO4 and using LBO as the intra-cavity SHG crystal With the optimization of laser cavity and crystal parameters, the laser operates at a very high efficiency. When the pumping power is about 31 W, the output at 457nm reaches 4.2 W, and the optical to optical conversion efficiency is about 13.5% accordingly. The stability of the out putpower is better than 1.2% for 8 h continuously working.     

Call for Papers

正Wireless Body-area Networks The last decade has witnessed the convergence of three giant worlds:electronics,computer science and telecommunications.The next decade should follow this convergence in most of our activities with the generalization of sensor networks.In particular with the progress in medicine,people live longer and the aging of population will push the development of wireless personal networks