温度及应力变化对光纤光栅布喇格波长的影响

着重讨论温度对光纤光栅的稳定性和反射谱的影响。分析了温度变化引起光纤光栅布喇格波长漂移的机理,为提高光纤光栅稳定性,对布喇格波长的温度漂移进行应变补偿。     

基于双光纤布喇格光栅的液位传感器

设计了一种基于双光纤布喇格光栅的新型液位传感器,导出了双光纤布喇格光栅的波长漂移差与液位的关系.圆盘上受到的液体压力导致等腰三角形悬臂梁变形,从而导致安装在悬臂梁两边的光纤布喇格光栅的布喇格波长漂移.通过检测两个布喇格光栅的波长漂移差,得到被测液位.双光纤布喇格光栅通过补偿温度效应,解决了光纤布喇格光栅传感器的交叉敏感问题.该液位传感器的动态测量范围为2～3 000 mm.实验表明,双光纤布喇格光栅的中心波长随液位的增加分别向长波和短波方向漂移,而带宽几乎不变,实验和理论符合较好,该设计方案是切实可行的.     

光纤光栅布喇格波长随温度和应力的变化特性及其补偿

主要用实验数据简要叙述了光纤光栅中布喇格波长随温度和应力变化呈良好的线性关系,并介绍了一种温度补偿装置,能有效抑制光纤光栅的布喇格波长随温度的漂移。     

温度不灵敏光纤光栅

提出了一种小型的实现温度补偿的光纤光栅组件.该器件包括两种具有不同热膨胀系数的物质.通过改变加在光纤光栅上的应变可以补偿温度变化引起的光栅布喇格波长的漂移.该组件在-20～40℃的温度范围内.波长变化仅有0.12nm.是未补偿光纤光栅的1/6.     

基于温度补偿高双折射光纤环镜的边缘滤波解调方法

提出了一种光纤光栅传感解调新方法。系统由1个3dB耦合器、1个传感光纤布喇格光栅、1个双折射光纤环镜和1个探测器构成,高双折射光纤环镜作为边缘滤波器。光纤光栅波长的线性解调带宽为3．6nm。对双折射光纤环镜的温度补偿进行了实验研究,实验表明,封装的高双折射光纤环镜能够补偿高双折射光纤环镜的温度漂移。补偿前的高双折射光纤环镜波长随温度漂移为2．3nm／℃,补偿后的双折射光纤环镜波长随温度漂移为0．005nm／℃,远小于未补偿的双折射光纤环镜波长随温度漂移。     

双体光栅外腔二极管激光器光谱特性研究

为了研究双体布喇格光栅外腔二极管激光器的衍射特性,采用一块体布喇格光栅与一块横向啁啾体布喇格光栅组成双体布喇格光栅,理论分析了组合前后体布喇格光栅的衍射特性,实验研究了双体布喇格光栅外腔二极管激光器的输出光谱特性。结果表明,在双体布喇格光栅外腔反馈的作用下,可以实现双波长同时输出,通过横向移动横向啁啾体布喇格光栅,可以在保持其中一个中心波长不变的情况下,使另外的一个波长在800nm~815nm的范围内线性调谐。此研究为基于双体布喇格光栅实现双波长输出的大功率二极管激光器提供了实验指导。     

光纤光栅外腔半导体激光器波长调谐方法研究

可调谐光纤光栅外腔半导体激光器（FBG-ECL）激射波长由光纤光栅布喇格波长决定,调谐光纤光栅布喇格波长可以改变激光器的激射波长.重点介绍采用轴向应力、径向应力和温度对光纤光栅布喇格波长的调谐.布喇格中心波长的偏移与轴向应力、径向应力和温度等变化量均呈极好的线性比例关系,且在较大的测量范围内一直保持线性关系.详细说明了光纤光栅外腔半导体激光器采用这三种方法调谐时的特点、适用范围,并对它们的性能进行了比较,给出在不同条件下适合的调谐方法.     

纵向应力法制作双波长布喇格光栅

介绍了一种用一个均匀相位模板制作双波长布喇格光栅的方法;对这种方法制作的双波长布喇格光栅进行了理论分析,用矩阵分析法,对其进行了数值模拟.采用了移动曝光技术,通过调节所加应力的大小、光栅长度及曝光次数可以控制两个布喇格波长的间隔和反射率;写制了一个双波长光栅,两个透射峰均为19.5 dB,两个布喇格波长的间隔为0.78 nm.     

光纤布喇格光栅应变传感器

1光纤布喇格光栅传感器和仪器光纤布喇格光栅（FBG）的制作方法是将～1cm的光纤在紫外激光器的两束光形成的干涉图中曝光．干涉条纹的明暗周期＝0．6～1μm,使光纤芯的折射率产生周期性的变化．这种折射率的调制在曝光后被保留下来,并且在～300℃的温度下是稳定的。当光线沿光纤传递时波长等于光栅的布喇格波长的那些光被反射．光栅的布喇格波长由下式定义：他一Zne,A＝ne。入／sin（0／）式中nefr是光纤芯的有效折射率,A是折射率的调制周期,AL是激光波长,0是光束之间的角度。FBG是一个窄带反射滤光器,其波长可以通过改变两相交…     

光纤布喇格光栅(FBG)传感器封装技术的研究

光纤布喇格光栅传感器的应变、温度交叉敏感特性是影响实用化的关键因素,封装是解决这一问题的主要手段.该文通过对比保护性封装、增敏性封装和温度补偿(或分离)等3种光纤布喇格光栅传感器封装的形式与各自的优缺点和应用场合,探讨了光纤布喇格光栅传感器的封装要点和需要注意的问题.     

Development of the readout system for waveguide multilayer optical card

Waveguide multilayer optical card （WMOC） is a novel storage device of three-dimensional optical information. An advanced readout system fitting for the WMOC is introduced in this paper. The hardware mainly consists of the light source for reading, WMOC, motorized stages addressing unit, microscope imaging unit, CCD detecting unit and PC controlling ＆ processing unit. The movement of the precision motorized stage is controlled by the computer through Visual Basic （VB） language in software. A control panel is also designed to get the layer address and the page address through which the position of the motorized stages can be changed. The WMOC readout system is easy to manage and the readout result is directly displayed on computer monitor.     

Nanoimprint Lithography -A Next Generation High Volume Lithography Technique

IntroductionNanoimprint Lithography is a well-acknowl-edged low cost, high resolution, large area pattern-ing process. It includes the most promising methods,high-pressure hot embossing lithography (HEL) [2],UV-cured imprinting (UV-NIL) [3] and micro contactprinting (m-CP, MCP) [4]. Curing of the imprintedstructures is either done by subsequent UV-lightexposure in the case of UV-NIL or by cooling downbelow the glass transition temperature of the ther-moplastic material in case of HEL…     

Collinear phase-matching study of terahertz-wave generation via difference frequency mixed in GaAs and Inp

The collinearly phase-matching condition of terahertz-wave generation via difference frequency mixed in GaAs and InP is theoretically studied. In collinear phase-matching, the optimum phase-matching wave hands of these two crystals are calculated. The optimum phase-matching wave bands in GaAs and lnP are 0.95-1.38μm and 0.7-0.96μm respectively. The influence of the wavelength choice of the pump wave on the coherent length in THz-wave tuning is also discussed. The influence of the temperature alteration on the phase-matching and the temperature tuning properties in GaAs crystal are calculated and analyzed. It can serve for the following experiments as a theoretical evidence and a reference as well.     

Effects of the alloy compositions on the phonon-polaritons in ternary mixed crystals

Composition dependence of bulk and surface phonon-polaritons in ternary mixed crystals are studied in the framework of the modified random-element-isodisplacement model and the Bom-Huang approximation. The numerical results for Several Ⅱ - Ⅵ and Ⅲ- Ⅴ compound systems are performed, and the polariton frequencies as functions of the compositions for ternary mixed crystals AlxGa1-xAs, GaPxAS1-x, ZnSxSe1-x, GaAsxSb1-x, GaxIn1-xP, and ZnxCd1-xS as examples are given and discussed. The results show that the dependence of the energies of two branches of bulk phonon-polaritons which have phonon-like characteristics, and surface phonon-polaritons on the compositions of ternary mixed crystals are nonlinear and different from those of the corresponding binary systems.     

Influence of PVK ： NPB hole transporting layer on the characteristics of organic light-emitting devices

A doping system consisting of NPB and PVK is employed as a composite hole transporting layer （CHTL）. By adjusting the component ratio of the doping system, a series of devices with different concentration proportion of PVK ： NPB are constracted. The result shows that doping concentration of NPB enhances the competence of hole transporting ability, and modifies the recombination region of charge as well as affects the surface morphology of doped film. Optimum device with a maximum brightness of 7852 cd/m^2 and a power efficiency of 1.75 lm/W has been obtained by choosing a concentration proportion of PVK ： NPB at 1：3.     

New insert layer structure OLEDs

An insert layer structure organic electroluminescent device（OLED） based on a new luminescent material （Zn（salen）） is fabricated. The configuration of the device is ITO/CuPc/NPD/Zn（salen）/Liq/LiF/A1/CuPc/NPD/Zn（salen）/Liq/LiF/A1. Effective insert electrode layers comprising LiF（1nm）/Al（5 nm） are used as a single semitransparent mirror, and bilayer cathode LiF（1 nm）/A1（100 nm） is used as a reflecting mirror. The two mirrors form a Fabry-Perot microcavity and two emissive units. The maximum brightness and luminous efficiency reach 674 cd/m^2 and 2.652 cd/A, respectively, which are 2.1 and 3.7 times higher than the conventional device, respectively. The superior brightness and luminous efficiency over conventional single-unit devices are attributed to microcavity effect.     

Analysis of error performance on Turbo coded FDPIM

Due to variable symbol length of digital pulse interval modulation（DPIM）, it is difficult to analyze the error performances of Turbo coded DPIM. To solve this problem, a fixed-length digital pulse interval modulation（FDPIM） method is provided. The FDPIM modulation structure is introduced. The packet error rates of uncoded FDPIM are analyzed and compared with that of DPIM. Bit error rates of Turbo coded FDPIM are simulated based on three kinds of analytical models under weak turbulence channel. The results show that packet error rate of uncoded FDPIM is inferior to that of uncoded DPIM. However, FDPIM is easy to be implemented and easy to be combined, with Turbo code for soft-decision because of its fixed length. Besides, the introduction of Turbo code in this modulation can decrease the average power about 10 dBm, which means that it can improve the error performance of the system effectively.     

A method for calculating the center position of collimated light

It is a key problem to accurately calculate beam spots＇ center of measuring the warp by using a collimated laser. A new method, named double geometrical center method （DGCM）, is put forward for the first time. In this method, a plane wave perpendicularly irradiates an aperture stop, and a charge couple device （CCD） is employed to receive the diffraction-beam spots, then the geometrical centers of the fast and the second diffraction-beam spots are calculated respectively, and their mean value is regarded as the center of datum beam. In face of such adverse instances as laser intension distributing defectively, part of the image being saturated, this method can still work well. What＇s more, this method can detect whether an unacceptable error exits in the courses of image receiving, processing and calculating. The experimental results indicate the precision of this method is high.     

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.     

Preparation and Characterization of TaN ALD Precursors

High purity organic-tantalum precursors for thin film ALD TaN were synthesized and characterized.Vapor pressure and thermal stability of these precursors were studied.From the vapor pressure analysis,it was found that TBTEMT has a higher vapor pressure than any other published liquid TaN precursor,including TBTDET,TAITMATA,and IPTDET.Thermal stability of the alkyl groups on the precursors was investigated using a 1H NMR technique.The results indicated that the tertbutylimino group is the most stable group on TBTDET and TBTEMT as compared to the dialkylamido groups.Thermal stability of TaN precursors decreased in the following order:TBTDET ＞ PDMAT ＞ TBTEMT.In conclusion,precursor vapor pressure and thermal stability were tuned by making slight variations in the ligand sphere around the metal center.