微结构光纤制备中的问题分析

分析了微结构光纤制备过程中存在的一些问题,简述了温度、空气孔中的空气压力、表面张力等因素对微结构光纤中毛细管形变的影响.建立了可行的制备技术工艺路线.同时比较了微结构光纤预制棒制作的不同方法,详细介绍了改进的堆积法方案.     

微结构聚合物光纤套管法拉丝工艺

通过对微结构聚合物光纤拉丝工艺的研究,提出微结构聚合物光纤二次预制棒套管拉丝技术.为了降低光纤拉伸过程中微孔坍塌率,从光纤拉伸力和材料表面张力之间平衡的角度考虑,对拉丝炉中热区温度和长度进行控制,得到了预制棒拉丝炉和光纤拉丝炉中热区温度分布曲线.最后,通过对本体聚合法制备的椭圆芯六角对称微结构聚合物光纤预制棒的拉丝实践...     

问与答

问与答问：裸光纤、光纤素线和光纤芯线有什么不同？答：１．裸光纤用预制棒拉制细光纤时，首先要将预制棒加热到高温（约２０００℃），使其变软后进行拉丝。在拉丝时要严格保持预制棒内已形成的折射率分布。对于这种刚刚拉制出来而尚未进行一次涂覆的光纤称为裸光纤。２...     

利用非化学汽相沉积法制备掺Yb^3＋光子晶体光纤的研究

提出了一种制备掺Yb^3＋光子晶体光纤（PCF）的新方法,即：非化学气相沉积法。利用溶液掺杂法,将SiO2、YiCl3、AlCl3、K2CO3材料在水溶液中混合,再蒸发、烘干得到均匀的混合材料,经2 000℃以上高温熔炼制备出高掺Yb^3＋浓度石英玻璃。用掺Yb^3＋石英玻璃作为纤芯,通过堆积法制备光纤预制棒,再经拉丝...     

一种耐高温光纤的制备方法

耐高温光纤涂料聚酰亚胺采用电炉加热,固化的时间长,不能满足大预制棒高速拉丝中长距离涂覆和快速固化的要求。本文介绍一种利用MCVD＋VAD工艺制作预制棒,在高速拉丝机上进行聚酰亚胺涂覆、快速固化的长距离耐高温光纤的制备方法。     

POF在三方面的最新进展

聚合物光纤（POF）和微结构POF（MPOF）分别是数据通信和不同类型传感器应用中“最后一百米”最有前途的解决方案。但为了进一步开发新型POF，需要在预制棒制造新工艺、新型光纤拉丝设备和POF的新应用三个方面进行研发。在POF拉丝过程中，采用普通电阻炉加热，沿预制棒径向会不可避免地产生大的温度升降。为了克服这一问题，开发出一种具有红外（IR）炉和普通电阻炉两种加热方法的新型加热炉。采用1．2μ波长的IR加热装置进行IR加热。因此，可以采用较大直径的预制棒并提高拉丝速度。制造出多个阶跃折射率新型预制棒用于开发工作。采用带有旋转管的车床装置进行预制棒制造。当观察到UV激活不足时，高效施加热激发径向聚合反应并对反应加以控制。通过在高温和高压下聚合预制棒芯使预制棒最终成型，由此获得的预制棒不需要缩棒。对POF深入细致的研究和开发包括两种标准折射率导引光纤以及用于激光器、放大器、非线性信号处理和生物光子应用的微结构POF。这样可以进一步扩展POF的有效应用范围。芬兰和丹麦的几位研究人员证明，此项研究工作是独创的，以前没有介绍或公布过。     

降低单模光纤损耗的工艺研究

结合光纤散射机理分析,从光纤预制棒折射率分布、掺杂浓度、拉丝张力和拉丝热处理等方面着手研究,通过优化预制棒沉积工艺和改善拉丝条件来制备低损耗单模光纤,并采用光时域反射仪(OTDR)进行检测,结果表明,单模光纤在满足ITU-T G.652标准的同时,在1 550nm波长的衰减可进一步降低。     

天然石英砂制造通信光纤的研究

将PSOD(等离子固态外部沉积)、光纤预制棒制备技术以及光纤拉丝技术相结合,成功开发了芯棒+天然石英砂套管的预制棒制备技术。该技术以成本相对较低的天然石英砂为原料,等离子体为热源,干燥压缩空气为工作气体,熔制了符合光纤生产要求的套管,并研究出了合适的光纤生产工艺路线。该套管的工艺路线简单,无需合成套管工艺中的脱水和烧结处理,且生产过程不会产生有毒有害的尾气,对环境无污染。针对天然石英砂材料的特殊性质,制定了低掺杂的预制棒沉积技术以及高张力拉丝的工艺条件,成品光纤各方面合格,并具有更低的衰耗。     

大尺寸预制棒高速拉丝技术研究

本文对Φ120-200mm预制棒、2000m/min高速拉丝技术进行了较为深入的研究.分别介绍了大尺寸预制棒高速拉丝对光纤衰减、翘曲度、不圆度、包层直径波动和强度方面的影响。通过对拉丝炉结构和光纤退火装置的改造,优化了拉丝炉温场和气流分布.大大改善了大尺寸预制棒高速拉丝光纤衰减、翘曲度、不圆度、包层直径波动和强度性能。     

光纤预制棒保温工艺的研究

通过Masao Kawach等建立的烧结终止阶段封闭球形气孔模型烧结条件介绍了光纤预制棒中氦气的产生原因。保温工序可以减少石英玻璃内的气孔以降低光纤预制棒内的He,He在石英玻璃中的扩散机理符合Fick定律,据此分析出了在微正压条件下烧结的光纤预制棒,通过保温处理后,氦气在光纤预制棒内的浓度分布符合正态分布。试验结果显示,延长保温时间,光纤预制拉丝时裸纤气泡减少;保温时间不变,光纤预制棒直径增大,拉丝时裸纤气泡增多。文章的研究成果将对不同半径光纤预制棒保温工艺的设置具有积极的指导意义。     

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.     

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.     

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.     

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.     

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.     

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.     

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