一种具有亚波长光栅结构的光探测器的设计

高速智能光纤通信系统和网络的飞速发展对光电探测器提出了更高要求.利用严格耦合波(RCWA)理论,给出了在亚波长光栅(SWG)下方具有分布布拉格反射镜(DBR)结构的理论分析模型,将这种结构作为反射镜应用于谐振腔增强型光探测器(RCE PD)的设计中.仿真表明由于SWG的引入,只需要4对λ/4厚度的InGaAsP/InP系DBR,可使整体膜系结构实现在中心波长1.55 μm处反射率达到99.7%,在1.40 μm至1.62/μm范围内反射率高于99%.引入SWG后的RCE PD在1.55 μm附近的量子效率接近90%,串扰衰减系数与量子效率的乘积超过15 dB.有效地解决了InGaAsP/InP介质膜系DBR作为谐振腔反射镜反射率低、反射带宽窄的问题.     

GaAs/GaInNAs多量子阱谐振腔增强型长波长光探测器

报道了一种具有高速响应特性的GaAs基长波长谐振强增强型(RCE)光探测器,它采用分子束外延技术(MBE)在GaAs衬底上直接生长GaAs/AlAs布拉格反射镜(DBR)和GaInNAs/GaAs多量子阱吸收层而形成,解决了GaAs系材料只能对短波长光响应的问题,实现了GaAs基探测器对长波长光的响应。该器件在峰值响应波长1296.5nm处获得了17.4%的量子效率,响应谱线半宽为11nm,零偏置时的暗电流密度8.74×10-15A/μm2,具有良好的暗电流特性。通过RC常数测量计算得到器件的3dB带宽为4.82GHz。     

共振腔增强GaInAsSb光电探测器设计及数值模拟

设计了一种从衬底入射的共振腔增强型GalnAsSb／GaSb光电探测器结构。在这种结构中,上反射镜是由9．5～15．5个周期的InAs／GaSb QWS组成,下反射镜由3个周期的SiO2/Si QWS组成。器件上表面镀有一层高透射率的抗反射层。计算表明,在设计的工作波长2．4μm,器件可以获得大约(91～88)％的量子效率。在2～2．9μm波长范围器件的量子效率有两个峰,这使得器件可以作为双色探测器来工作。     

单片集成GaAs基长波长谐振腔光探测器的研究

介绍了一种GaAs基的长波长谐振腔增强型(RCE)光探测器.通过两步生长法,在GaAs村底上异质外延生长了InP-InGaAs-InP的p-i-n光吸收结构和GaAs/AlAs的分布布拉格反射镜(DBR).所制备的器件在1 549.4 nm处获得了67.3%的量子效率和17 nm的光谱响应线宽,在1 497.7 nm处获得了53.5%的量子效率和9.6 nm的光谱响应线宽,而InGaAs吸收层厚度仅为200 nm.采用单片集成法,工艺简单、易于产业化,随着缓冲层技术的发展,此种RCE光探测器的性能还将获得进一步提升.     

940nm VCSEL高折射率对比度亚波长光栅反射镜的设计

研究了一种940 nm GaAs基VCSEL的高折射率对比度亚波长光栅反射镜（HCG）,采用GaAs/AlO_x光栅结构,讨论了TE偏振时光栅结构中各参数对反射光谱的作用规律,分析TE、TM不同偏振时反射镜的结构特点,及形貌误差对高反射带的影响。设计的TE-HCG的高反射带中心为940 nm,在0.888～0.985 μm波长范围内,TE波反射率大于99.5%,TM波反射率低于90%,高反射带宽97 nm,Δλ/λ₀>10%。该反射镜可以与VCSEL采用一次性外延生长技术制作,且具有结构简单,制作容差大,且偏振稳定的优势,不仅有利于改善器件性能,且大大降低VCSEL的制作难度和成本。     

具有光束偏转功能的亚波长光栅偏振分束器

针对亚波长光栅偏振分束器无法实现垂直出射光 、集成耦合效率低的问题,本文设计了 一种具有光束偏转功能的亚波长光栅偏振分束器,可实现偏振分束且能获得垂直出射光。器 件上 层采用光栅衍射理论设计了可实现偏振分束的周期亚波长光栅,下层通过严格耦合波法与波 前相 位控制理论设计了具有光束偏转功能的非周期亚波长光栅。基于有限元软件COMSOL对设计 的器 件进行仿真分析,结果表明该器件可分开TE与TM混合偏振光且能实现光束垂直出射,两种 偏振 光的总透射率在1550nm处超过了76.5%,偏振 消光比为14.0 dB。因此通过该偏振分束器不但可 以获得垂直出射的单偏振光,而且能有效提高垂直耦合型器件的工作效率,有望应用在面向 光纤通信的集成光电器件中。     

长波长、高灵敏度的InP／InGaAs谐振腔光电探测器

本文报道了一种能够实现高速、高灵敏度的InP基谐振腔增强型（RCE）光电探测器。它采用衬底入光方式，解决了在InP衬底上外延生长的InP/InGaAs介质膜分布布拉格反射镜（DBR）反射率低的问题，该探测器的吸收层厚度为0.2μm，在波长1.583μm处获得了80%的峰值量子效率，同时为了降低探测器的固有电容，利用质子注入技术使得器件的部分电极绝缘，实验结果表明质子注入不影响RCE光电探测器的量子效率。     

1.3 μm InGaNAs/GaAs多量子阱"一镜斜置三镜腔"光探测器

报道了一种基于InGaNAs/CmAs多量子阱的1.3μm GaAs基"一镜斜置三镜腔"光探测器,采用分子束外延(MBE)技术在GaAs衬底上直接生长高质量的GaAl/AIAs分布布拉格反射镜(DBR)和InOaNAs/GaAs多量子阱吸收层,实现了单片集成的GaAs基长波长"一镜斜置三镜腔"光探测器.探测器的峰值响应波长位于1298.4 nm,光谱响应线宽(FWHM)为1.0 nm,量子效率为3%,在零偏压下其暗电流密度为3.75×10 13A/μm2.     

RCE光电探测器顶部DBR的优化

对研制的VCSEL结构外延片制成的谐振腔增强型（简称RCE）光电探测器进行了物理分析和实验研究,由于VCSEL与RCE光电探测器对谐振腔反射镜的反射率要求不同,通过腐蚀VCSEL器件顶部DBR,改变顶镜反射率,能够得到量子效率峰值和半宽优化兼容的RCE光电探测器,实现VCSEL与RCE探测器的单片集成．     

新型光电探测器的研究

针对RCE光电探测器存在的问题提出两种解决方案。将InP／空气隙的分布布拉格反射镜(DBR)结构引入RCE光探测器,只用1．5对InP／空气隙计算反射率约为95％,解决了长波长反射镜制备问题。所制备的器件,在波长1．585μm处获得了约54．5％的峰值量子效率,以及8GHz的3dB响应带宽。另一种引入斜镜结构解除了量子效率与超窄光谱响应线宽的相互制约。     

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.