光纤法珀传感器解调系统的设计

光纤法珀传感器具有测量精度高、动态范围大、可单端检测等优点。针对白光干涉型法珀传感器,设计了一种基于体光栅的光纤传感器解调系统。该系统采用高性能体光栅和线阵CCD阵列实现了光谱的采集,并结合高性能数据采集卡和PC机进行信号的处理和输出。测试结果表明该解调系统的温度测量精度在±1℃以上。     

光纤F—P和FBG传感器通用解调系统的研究

针对目前不同种类传感器在建筑结构及其工作环境进行实时监测应用上的实际情况,提出了一种利用可调F—P滤波器对光纤法珀传感器和光纤布拉格光栅传感器通用解调方案,研究了解调系统的组成和对传感器的解调原理．初步实验结果表明,系统能够对上述2种传感器进行解调,并具有复用能力,光纤法珀传感器的应变解调精度在2με以下,光纤布拉格光栅传感器解调精度在0．5με以下,是一种低成本、通用的解调系统．     

基于可调谐法珀腔解调的光纤法珀应变传感系统

本文提出了一种基于可调谐法珀腔解调的光纤法珀应变传感器系统，阐述了该系统的测量原理，提出了可调谐法珀腔的一种设计方案。     

一种基于F-P干涉仪的FBG解调系统信号重建算法

建立了基于可调谐法布里-珀罗(F-P)干涉仪的光纤光栅传感器解调系统,分析了解调系统输出信号噪声的主要来源和特点,设计了旁瓣抑制强的数字低通滤波器滤除噪声干扰,并根据最小二乘法原理对滤波后的电压信号波峰进行了高斯曲线拟合.通过实验得知,该算法能够有效地重建系统输出信号,提高解调系统的测量精度.     

啁啾光纤光栅法布里-珀罗传感器波分频分复用

实现了一种具有大容量复用潜力的啁啾光纤光栅(CFBG)法布里-珀罗(F-P)传感器复用系统。该传感器复用系统的建立基于波分频分复用方法,即中心波长相同的传感器利用腔长不同空间频率不同来实现空间频分的复用,采用不同中心波长的传感器阵列与频分复用方法相结合就可实现波分频分复用。描述了该光纤光栅法布里-珀罗传感器复用系统的结构、原理及应变实验结果。实验结果表明,该方法可以大大地提高光纤光栅法布里-珀罗应变传感器的复用能力,理论上可复用数百个光纤光栅法布里-珀罗应变传感器;实验中应变测量精度好于±10με,可满足大部分实际应用的要求。     

基于光纤光栅的传动齿轮模态分析

利用光纤光栅传感器实现了基于快速应变响应的传动齿轮模态分析。基于波分复用技术组建光纤光栅传感网络,根据光纤光栅的应变响应数据完成齿轮的应变模态分析,并与基于声压传感器的齿轮试验模态分析结果进行对比,固有频率相对误差小于0.1%。为了实现光纤光栅传感器的快速应变采集,搭建了一套光纤光栅快速解调仪。该解调仪是基于体相位解调的单通道快速解调仪,采样速率最高为35kHz,使用LabVIEW编写了光纤光栅信号采集和解调软件。基于光纤光栅的齿轮应变模态分析方法附加质量小,比传统加速度传感器测量结果更准确,能够适应小型齿轮箱内部复杂和恶劣的测量环境,具有一定的应用价值。     

基于光楔的光纤法-珀应变传感器解调系统原理研究

根据基于光楔的光纤法-珀应变传感器解调系统的结构,分析了解调系统的解调原理,并给出了仿真结果.得出当光楔厚度与法-珀传感器腔长相等时,其输出光强最大.通过实验结果与仿真结果的比较,说明基于光楔的光纤法-珀应变传感器解调系统在原理上是正确的.     

光纤法-珀非扫描式相关解调系统分析

为了提高解调精度,时间一致性和稳定性及降低仪器成本。利用非扫描式相关解调原理,设计了光纤法珀解调系统并进行了实验研究。建立光纤法珀解调系统的光学模型,进行了光学特性分析和参数优化;设计了光学系统和硬件解调系统。同时由于系统中存在大量背景光谱噪声、线性光分布不均匀及光纤端面的反射,导致不能准确检测出相关信号的极大值,为此提出了一种信号修正算法,能有效滤除噪声,提高了仪器的解调精度。实验结果表明:测量范围为10-40μm,分辨率为8nm,稳定性达到了7nm。该仪器能实现对传感器腔长的实时测量,且测量精度高、稳定性和一致性好。     

基于实时校准技术的光纤光栅传感解调系统

报道了一种采用实时校准技术的数字化光纤光栅传感解调方案。解调系统利用锯齿波电压信号和数字相位同步信号控制可调谐光纤法布里一珀罗(TFFP)滤波器，对光纤光栅传感器阵列进行扫描式寻址，同时采用非测量环境中的参考光栅和数字温度计提供精确的参考波长，并由高速数字信号处理器(DSP)实时校准滤波器的波长读取值，很好地消除了滤波器渊谐的温度漂移、非线性和蠕动性引起的测量误差。结果表明，实验系统的波长寻址范围为1520～1570nm，扫描频率为100Hz，波长测量分辨率为5pm，应变测量分辨率为4．13με。     

基于F-P滤波器的光纤光栅解调技术研究

介绍了光纤光栅传感器的解调原理,设计并实现了一个基于可调谐F-P滤波器的光纤光栅波长解调系统.利用数据采集卡采集光纤光栅的光谱数据上传给计算机,用LabVIEW编写了对数据进行实时处理的软件.实验结果表明该系统有效可行,可以获得±0.3℃的测量精度,并具有对50个以上的光纤光栅传感器进行解调的潜力.     

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.     

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.     

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.     

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.     

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.