Mach－Zehnder光纤干涉仪可见度分析

基于部分相干理论，导出高斯谱光源谱线宽度与干涉可见度的关系，为干涉型光纤传感器的系统设计提供了理论依据，并借助计算机绘制出干涉仪可见度与由于干涉仪两臂不平衡而引起传播时间差的关系曲线。     

一种针对使用背照减薄型CCD器件色散型成像光谱仪的星上光谱定标方法

使用背照减薄型CCD器件的色散型成像光谱仪在近红外波段会出现呈条带状干涉条纹现象,该干涉条纹对入射光波长分布敏感,空间频率稳定,特别适用于微小光谱偏差的测量与校准.针对一台光栅色散型推扫式成像光谱仪样机,先估计出条纹分布的规律,再以此为基础,采用频域滤波、最小二乘拟合等方法提取干涉条纹中包含的相位信息,以此作为光谱定标的辅助参数.实验表明,当入射光强变化达到130％以上时,拟合谱线位置的不确定度最大为0.007 3 nm,模拟光谱位置改变后,以汞灯谱线作为基准光谱位置曲线,测得拟合算法的最大误差为0.135 8 nm,该结果证明,干涉条纹拟合定标方法可有效减少定标系统对光源稳定性的依赖,提高对光谱维微小偏移量的检测精度.     

一种针对使用背照减薄型CCD器件色散型成像光谱仪的星上光谱定标方法（英文）

使用背照减薄型CCD器件的色散型成像光谱仪在近红外波段会出现呈条带状干涉条纹现象,该干涉条纹对入射光波长分布敏感,空间频率稳定,特别适用于微小光谱偏差的测量与校准。针对一台光栅色散型推扫式成像光谱仪样机,先估计出条纹分布的规律,再以此为基础,采用频域滤波、最小二乘拟合等方法提取干涉条纹中包含的相位信息,以此作为光谱定标的辅助参数。实验表明,当入射光强变化达到130%以上时,拟合谱线位置的不确定度最大为0.007 3 nm,模拟光谱位置改变后,以汞灯谱线作为基准光谱位置曲线,测得拟合算法的最大误差为0.135 8 nm,该结果证明,干涉条纹拟合定标方法可有效减少定标系统对光源稳定性的依赖,提高对光谱维微小偏移量的检测精度。     

分立双谱线的杨氏双缝干涉的计算机仿真

以分立双谱线的杨氏双缝干涉为研究对象,利用matlab软件对其实验现象进行数值仿真,研究了分立双谱线的线型和线宽对干涉条纹的可见度和强度分布的影响.发现分立双高斯形谱线比双矩形谱线更接近无限窄双谱线的干涉结果,谱线宽度越小,双高斯形或双矩形谱线的干涉图样越接近无限窄双谱线的干涉图样,即谱线宽度越小,谱线线型对干涉条纹的影响越小.     

基于环形透镜的菲索干涉仪环形光源设计

针对使用点光源的激光干涉仪在测量中容易出现相干噪声的问题,阐述了环形光源抑制相干噪声的原理,分析了环形光源半径及厚度与条纹可见度之间的关系,提出一种基于环形透镜产生环形光源的光学系统.该系统包括扩束系统、环形透镜和双远心镜头,根据菲索干涉仪中的准直镜头和干涉腔长得到环形光源的目标参数.使用Zemax分别设计了环形光源系...     

EFPI腔内损耗对干涉条纹可见度的影响

利用多光束干涉原理和几何光学方法,分析了非本征F-P干涉仪(EFPI)腔内损耗对干涉仪的影响,详细推导了EFPI腔长与反射光干涉条纹可见度之间的关系,确定了在可测条纹可见度的要求下EFPI腔长的范围.     

激光多普勒流速仪的干涉条纹理论分析及测量

激光多普勒流速仪(LDV)具有准确度高、非接触测量、动态响应快等优点,在流速测量中得到了广泛应用。条纹的非一致性是影响激光多普勒流速仪测量精度的重要因素,因此精确获知测量体中干涉条纹间距及梯度分布情况,是激光多普勒流速仪准确测量流速的前提。对激光多普勒流速仪测量体中的干涉条纹间距及梯度分布进行了理论分析,揭示了高斯光束固有传播特性与其测量体中干涉条纹分布之间的关系,确定了影响干涉条纹分布的参数。使用光束分析仪分别获得绿光和紫光的束腰半径为114μm和83μm,并确定了束腰的空间位置,利用测得的相关参数量化了绿光和紫光测量体中任意位置的干涉条纹间距及梯度分布,绿光和紫光测量体中归一化后的条纹梯度最大分别可达0.46%和0.60%。通过与转盘装置所测得的绿光和紫光干涉条纹间距结果进行比较,对干涉条纹分布的理论分析及测量结果进行了验证,最大相对误差分别为0.87%和0.78%。     

相干组束光纤激光干涉图样分布研究

为了研究两相干组束光纤激光的干涉图样的分布特征,采用数值计算和实验相结合的方法,对干涉图样进行了理论分析和实验验证,取得了在不同光束间距及不同傅里叶透镜焦距下的干涉图样分布图。干涉图样的条纹分布和条纹可见度主要受到激光光束间距、傅里叶变换透镜焦距以及光束束腰半径等参量的影响。随着光束间距的增大,干涉条纹间距减小,条纹数目增多,条纹可见度减小;傅里叶变换透镜焦距增大时,干涉条纹数目没有明显变化,条纹间距略有增加,条纹可见度增大。这一结果对相关实验工作将有一定帮助。     

电子散斑干涉图样及其模拟/数字混合处理

本文建立了一个电子散斑干涉(ESPI)系统。干涉图样经模拟电子处理,去掉散斑频谱以外的大部分噪声;再经数字图像处理,去掉散斑频谱内的残留噪声。与传统的ESPI系统相比,本系统大大提高了干涉条纹可见度,改善了测量精度。实验测量了几     

基于远场干涉测量棱镜内气泡直径

为了测量固态透明物质中气泡直径,采用远场干涉的方法测量玻璃棱镜中气泡直径。平行激光束照射到棱镜中的气泡时,在远场将产生圆环状干涉条纹,利用气泡远场干涉模型进行理论分析,并用分光仪对三棱镜外干涉条纹进行测量,取得一组关于干涉条纹角位置的数据,由折射定律换算为棱镜内干涉条纹角位置,进而使用计算软件MATH-EMATICA计算出气泡直径。结果表明,测量相对差为0.2%,所测气泡直径的方向应为入射激光束的方向,对气泡在载物台上方的位置要求不严格;对测量方法进行适当改变,亦可测量其它形状透明介质内的气泡直径。这一测量结果对透明物质中气泡形状的研究是有帮助的。     

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.     

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.     

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.     

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.     

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.     

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.