光纤光栅传感器的波长解调技术研究进展

光纤布喇格光栅(Fiber Bragg grating,简称光纤光栅:FBG)波长的解调是光纤光栅传感器应用的关键技术之一.在简单介绍光纤光栅传感原理的基础上,综述了近年来国内外多种光纤光栅波长解调系统的工作原理,分析了相应解调方法的优缺点,讨论了当前光纤光栅波长解调存在的技术难点,展望了其未来的研究方向.     

基于F-P滤波器的FBG解调系统改进及其寻峰算法对比分析

光纤布拉格光栅(FBG)传感器是一种新型传感器,有着非常广泛的应用前景,FBG传感信号解调是FBG传感器应用的关键技术之一。为提高可调谐F-P滤波器的解调精度,引入波长标准具加以改进,最后对几种寻峰算法进行误差比较,证明基于正交多项式最小二乘拟合法更适用于大容量分布式FBG传感网络的波长检测。     

简支梁调谐光纤光栅波长的改进算法

对使用简支梁调谐光纤光栅(FBG)波长的计算方法进行了分析,改进了传统计算公式,给出了计算光栅波长调谐量的解析式.与传统算法相比,改进算法可以直接通过梁的长度变化量计算得到波长调谐量,因此应用更加简便,可以更为直接地指导调谐实验.     

光纤布拉格光栅传感器的温度补偿研究

应力和温度变化引起光纤布拉格光栅(FBG)传感器中心波长漂移的交叉敏感效应制约了光纤布拉格光栅传感器的实用化。在简介光纤布拉格光栅传感器工作原理的基础上,综述了近年来国内外在该领域实现温度补偿的相关技术和消除或减弱传感器温度敏感的方法,阐述了光纤布拉格光栅传感器温度补偿的原理,并分析了每种方法的特点,探讨了光纤布拉格光栅传感器应用中存在的问题。     

光纤光栅传感器检测技术

阐述了光纤光栅传感器的波长移动检测技术的发展现状,分析各种检测技术的原理和性能,并对增益光纤在FBG传感网络有源检测中的应用进行探讨。     

基于光纤光栅级联调谐技术的波长检测系统

报道了一种检测光纤光栅传感器波长的新方案。实验系统采用新型的级联结构对电热调谐的光纤光栅滤波器进行复用,扫描分析传感信号光的峰值波长,同时用参考波长校准方法消除了电热调谐中的蠕动误差。结果表明,系统的检测范围可达23nm,波长分辨率为3.1pm,应变测量分辨率为2.56με。     

少模光纤布喇格光栅的光谱特性研究

相较于传统的单模光纤布喇格光栅(FBG)传感器,少模FBG传感器在测量时不易受到外界无关参量的影响,精度更高,但其在光栅参数设计上缺乏相应的理论依据。针对此问题,基于FBG耦合模理论,利用OptiGrating和Matlab软件模拟分析了纤芯中存在LP₀₁模、LP₁₁模的少模FBG的反射谱。仿真结果表明:区别于传统单模FBG的单峰结构,少模FBG的反射谱具有三峰结构,光栅周期、光栅长度和折射率调制深度的变化会对各波峰的反射率及中心波长产生规律性的影响。     

基于F-P腔滤波器的FBG温度传感器解调技术

近些年来,光纤光栅传感器成了传感领域的研究热点.对高精度的波长编码信号解调是实现光纤光栅传感的关键技术.介绍了光纤布拉格光栅(FBG)传感器的工作原理,同时对F-P腔滤波器的工作原理进行了分析,阐述了光纤光栅传感器解调技术的发展趋势,并提出了光纤光栅传感器解调技术需要解决的技术问题.     

商用仪器化的FBG传感器检测系统

综述光纤布喇格光栅(FBG)传感器的工作原理、波长解调技术、应变和温度同时测量的问题.经过十多年发展,光纤光栅传感器已广泛应用于各种领域.通过具体分析国外某公司光纤光栅传感器检测系统的产品性能指标,表明光纤光栅传感器业已解决了本身的许多技术关键和实际工程中的使用问题,进入商用仪器化实用阶段,市场前景看好.我国光纤光栅传感器处于试验性试用阶段,和国外有较大差距,我们应引起足够重视.     

基于SoC的光纤光栅温度传感器

波长漂移量的精确检测是光纤光栅(FBG)传感器的关键技术.设计了基于芯片系统(SoC)的FBG温度传感器,通过控制激光器工作波长,跟踪锁定FBG反射波长,实现温度传感解调,具有信噪比高、可靠性好、成本低、硬件简单、软件灵活并具有智能化等优点,有良好的应用发展前景.     

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.