水填充太赫兹空芯布拉格光纤温度特性研究

空芯太赫兹(Terahertz,THz)光纤因其损耗低 和易集成功能材料等优点是当前 研究热点。液态水在太赫兹频段具有的独特性质使其在太赫兹辐射、传感和器件等方面具有 多种潜在应用。本文设计一种带有水缺陷层的太赫兹空芯布拉格光纤(hollow core Bragg fiber,HCBF),并采用有限元法分析了其温度特性。结果表明,设计的太赫兹光纤在0.34 THz到0.44 THz频段内存在明显的温度可调的吸收峰,且限制损耗随 着水温的升高而增加。 同时,光纤具有较高的核芯功率比,其值均大于98.6%。本文所研究 的水填充太赫兹光纤在 研究太赫兹与液体相互作用、太赫兹调控器件等领域具有潜在的应用价值。     

偏振可调的太赫兹单偏振单模光子晶体光纤

采用折射率匹配耦合法,提出了一种偏振可调的单偏振单模太赫兹光纤。通过在纤芯设计非对称微结构来实现芯模x、y偏振模式的分裂;在包层空气孔中填充折射率匹配液来引入缺陷模式,通过调整液体折射率来分别实现它与芯模x、y偏振模式的匹配。结果表明,当液体折射率为1.288时,x偏振模式匹配。当入射光频率大于0.73THz时,偏振损耗比大于100,光纤以y偏振模式运转;当入射光频率为1THz时,偏振损耗比达到最大值1020。当液体折射率为1.338时,y偏振模式匹配。当入射光频率在0.87~0.93THz时,偏振损耗比大于100,光纤以x偏振模式运转;当入射光频率为0.9THz时,偏振损耗比达到最大值118。该设计实现了光纤单偏振运转模式的切换,具有宽带、可调、易于实现的特点。     

2~5 THz宽频段多孔纤芯高双折射太赫兹光子晶体光纤

提出了一种以Topas环烯烃共聚物为基底,采用级联六边形单元多孔纤芯结构的宽频带高双折射太赫兹光子近10~(-1))的超高双折射,10~(-12)dB/cm的超低限制损耗,以及小于1 cm~(-1)的有效材料吸收损耗。此外,所提出的结构在2.25～5 THz的频带内表现出±0.2 ps/THz/cm的近零平坦色散。该光纤所实现的双折射值不仅是迄今已知太赫兹聚合物光纤中最高的,而且其新颖的多孔纤芯结构设计有效降低了太赫兹波的传输损耗。同时,光纤结构均采用圆形空气孔,便于工程制备,该工作对今后太赫兹光子晶体光纤的发展具有一定的参考价值。     

基于双开口环型的太赫兹超材料传感器设计

设计了一款可用于检测材料折射率及厚度的双开口环型太赫兹超材料传感器,其结构由双开口方环与圆环嵌套的超材料结构和聚酰亚胺衬底两部分构成.当太赫兹波垂直入射超材料表面时,该传感器结构在0.8～1.8 THz范围内形成三个高Q值谐振峰(中心频率分别为f1,f2和f3).通过探讨超材料结构表面电流分布与三个谐振峰形成的关系,观察到超材料结构对入射太赫兹波的不同响应特性导致产生不同的表面电流分布.此外,还对该传感器在折射率传感和厚度传感方面的应用进行了探究.在待测物厚度一定的情况下,该传感器在谐振频率f1,f2和f3处的传感灵敏度分别可达170,103和119 GHz/RIU,均具有优越的传感特性,可利用其多谐振峰进行高灵敏度折射率传感.这种高灵敏度的多谐振峰折射率传感器可以检测到待测分析物的微小变化,在生物化学检测领域具有广阔的应用前景.     

基于表面等离子体共振的光子晶体光纤折射率传感器的设计与分析

为了实现光子晶体光纤在近红外波段下的高灵敏度传感,设计了一种基于表面等离子体共振的光子晶体光纤(SPR-PCF)折射率型传感器。光纤内部的空气孔呈六边形排列,金纳米层完全包覆光纤外璧并与圆形待测物通道接触。利用有限元矢量软件COMSOL对SPR-PCF传感器的光学特性进行数值模拟仿真,得到不同待测物折射率的共振波长并绘制出纤芯损耗光谱,通过纤芯损耗光谱来对SPR-PCF传感器的传感特性进行分析。实验结果表明,其折射率测量区间为1.31~1.38,最大光谱灵敏度为104 nm/RIU,最大振幅灵敏度为200RIU-1,折射率测量精度为2.94×10-5RIU。     

垂直双空芯宽带太赫兹偏振分离器

针对太赫兹波的特点,利用折射率匹配耦合原理,设计了一种垂直双空芯结构的偏振分离器件。与传统的分离器件相比,它具有以下优点:（1）双芯折射率匹配度高,使得对应的偏振模式所需要的分离长度很短;（2）采用双空气纤芯结构,降低材料对太赫兹波的吸收损耗;（3）通过设计,令其发生耦合的两个纤芯相互垂直,从而使y偏振模的折射率曲线部分重合,大大扩展了工作带宽的范围,其工作带宽达到了0.17 THz。此外,由于器件结构简单对称,降低了光纤的设计和制备难度,使其在太赫兹网络中具有很高的应用价值。     

环烯烃共聚物空芯微结构太赫兹光纤的设计与制造

以环烯烃共聚物（cyclic-olefin copolymer,COC）材料为基质,设计、制造了一种空芯多孔包层太赫兹（THz）纤维。利用comsol 软件模拟了芯径为6 mm 的光纤在0.2~1.5 THz 波段的损耗特性,结果表明:在0.85~1.5 THz 波段存在多个低损耗频带,而且在0.85~1.1 THz 波段有低于3 dB/m 的三个窗口;特别是在0.99 THz,损耗达到0.208 dB/m。芯径为3 mm、4.8 mm 和6 mm 的光纤在0.8~1.5 THz 波段的损耗特性对比分析表明:该COC 微结构多孔包层空芯纤维的损耗随着光纤外径的增加而减小。把设计的太赫兹纤维外径放大7 倍达到7 cm,据此设计制造了光纤预制棒成型专用模具。借助热挤出成型方法得到了结构完整、孔洞表面光滑,长度为22 cm 的空芯多孔包层预制棒。利用该实验室独有的微结构光纤拉丝塔,成功获得了微结构保持完好的光纤样品。损耗分析结果表明:6 mm 芯径的光纤样品在1.27 THz 的平均损耗为2.175 dB/m,与该频率的理论损耗（1.95 dB/m）接近。     

基于亚波长悬浮芯光纤的高灵敏度气体传感器(英文)

数值分析了亚波长悬浮芯光纤在气体传感方面的应用。利用有限元法研究了相对灵敏度、有效模场面积、限制损耗与光纤参数包括纤芯直径和光纤材料折射率之间的关系。结果显示,相对灵敏度和限制损耗随着纤芯直径和光纤材料折射率的降低而增加。随着纤芯直径的减小,有效模场面积出现了先减小后增加的现象。增加包层孔直径能有效降低限制损耗,而相对灵敏度和有效模场面积保持不变。这些结果证明,亚波长悬浮芯光纤非常适合成为高灵敏度、大有效模场面积、低限制损耗的气体传感器。     

基于侧边抛磨多模光纤的高灵敏度折射率传感器

提出一种可于生物传感的侧边抛磨多模光纤(SPMMF)折射率传感器。针对1.300~1.430折射率范围传感特性,研究了纤芯直径50.0、62.5和105.0μm的多模光纤(MMF)侧边抛磨不同深度时SPMMF折射率传感器的光谱特性和光功率传输特性。结果表明,在1.300~1.430折射率范围内,光纤纤芯直径和剩余半径(抛磨面到纤芯中心的距离)越小,传感器灵敏度越高;纤芯直径为50.0μm、剩余半径为0μm时,可以获得最高达42.23dB/RIU的灵敏度,最小分辨率为2.37×10-5RIU;纤芯直径为105.0μm、剩余半径30μm时,SPMMF折射率传感器仍有10-5 RIU量级的分辨率。     

基于折射率调制原理的光纤生物传感器的研制

根据光纤内光强损耗与芯外的环境有效折射率之间的关系,设计了一种结构简单、易于操作、成本低廉、灵敏度较高的折射率调制型的光纤生物传感器.文中对该传感器的结构进行了理论分析,通过对不同浓度葡萄糖溶液的检测,研究了该传感器的传感特性.结果表明:该传感器的检测灵敏度可以达到μmol/L量级,并具有较好的线性特性.     

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.     

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     

Call for Papers—Feature Topic,Vol.12,No.7,2015

正Information Centric Networking Information-Centric Networking(ICN) is an emerging direction in Future Internet architecture research,gaining significant tractions among academia and industry.Aiming to replace the conventional host-to-host communication model by a data-centric model,ICN treats data content as the first