纳米压印制作半导体激光器的分布反馈光栅

分布反馈(DFB)光栅的制作是半导体激光器芯片的关键工艺,通过纳米压印技术在InP基片表面涂覆的光刻胶上压印出DFB光栅图形,并分别通过湿法腐蚀和干法刻蚀技术将光栅图形转移到InP基片上。所制作的DFB光栅周期为240nm(对应于1 550nm波长的DFB激光器),光栅中间具有λ/4相移结构。采用纳米压印技术制作的DFB光栅相对于通常双光束干涉法制作的光栅具有更好的均匀性以及更低的线条粗糙度,而且解决了双光束干涉法无法制作非均匀光栅的技术难题。相对于电子束直写光刻法,采用纳米压印技术制作DFB光栅具有快速与低成本的优势。采用纳米压印技术在InP基片上成功制作具有相移结构的DFB光栅,为进一步进行低成本高性能的半导体激光器芯片的制作奠定了良好基础。     

全息光刻制备808nm分布反馈半导体激光器的光栅

实验优化设计了808 nm分布反馈(DFB)半导体激光器的二级布拉格光栅结构,介绍了808 nm DFB半导体激光器光栅制备的工艺过程。采用全息光刻方法和湿法腐蚀技术在Ga As衬底片上制备了周期为240 nm的光栅图形,全息光刻系统采用条纹锁定技术降低条纹抖动和提高干涉稳定性,腐蚀液中H3PO4、H2O2和H2O的体积比为1:1:10,腐蚀时间为30 s。光学显微镜、扫描电子显微镜(SEM)和原子力显微镜(AFM)测试显示,光栅周期为240 nm,占空比为0.25,深度为80 nm,具有完美的表面形貌及良好的连续性和均匀性。     

808nm DFB半导体激光器的光栅制备

实验优化设计了808nm DFB半导体激光器的二级布拉格光栅结构,介绍了808 nm分布反馈（DFB）半导体激光器光栅制备的工艺过程。采用全息光刻方法和湿法腐蚀技术在GaAs衬底片上制备了周期为240nm的光栅图形,全息光刻系统采用条纹锁定技术降低条纹抖动和提高干涉稳定性,腐蚀液采用H3PO4 : H2O2 : H2O (1 : 1 : 10),腐蚀时间为30s。光学显微镜、扫描电子显微镜（SEM）和原子力显微镜（AFM）测试显示,光栅周期为240nm,占空比为0.25,深度为80nm,具有完美的表面形貌,及良好的连续性和均匀性。     

28mA,10mW带相位调整功能的DFB激光器

日本富士通研用分段改变隐埋条宽的方法,制作出GaInAsP/InP带相位调整功能的DFB激光器。DFB(分布反馈型)激光器是长距离大容量光传输系统用有希望的光源。最近,这种激光器的阈值进一步降低,并采用了相位调整技术。器件制作,先进行第一次生长,在刻有衍射光栅的n型InP衬底上生长n型GaInAsP波导层(0.13μm厚)、GaInAsP有源层(0.15μm)。接着把生长衬底腐蚀成台面条型,这时为了限制电流,采用了InP的pn结。另外,为了防止由于条宽的急剧变化而引起的异常生长,设置了5μm的锥形区。这样,进行第二次隐埋生     

用于1.55μm InGaAsP/InP DFB激光器的λ/4相移衍射光栅

采用全息二次曝光的方法,研制出用于 1.55μm InGaAsP/InP DFB激光器的,具有 λ/4相移的二级光栅,并通过扫描电镜(SEM)证明了相移的存在.本文分析了制备该种光栅的工艺原理,并提出了改善此种光栅质量的新方法.     

808 nm半导体分布反馈激光器的光栅设计与制作

半导体分布反馈（ DFB）激光器的核心工艺之一是分布反馈光栅的制作，设计了808 nm DFB激光器的一级光栅结构。利用纳米压印技术与干法刻蚀附加湿法腐蚀制作了周期为120 nm的梯形布拉格光栅结构，使用MATLAB和Pics3D软件模拟了一次外延结构的光场分布和能带图。通过优化湿法腐蚀所用腐蚀液各组分比例、腐蚀温度、腐蚀时间等条件，得到了理想的湿法腐蚀工艺参数。扫描电子显微镜表征显示，光栅周期为120 nm，光栅深度约为85 nm，占空比约为47%，光栅边缘线条平直，表面平滑，周期均匀。创新型的引入湿法腐蚀工艺和腐蚀牺牲层使光栅表面的洁净度得到保证，提高了二次外延质量的同时，也为进一步制作DFB激光器高性能芯片奠定了良好的基础。     

10Gbit/s高T0无制冷分布反馈激光器

与折射率耦合分布的分布反馈(DFB)激光器相比,不管界面反射率是多少,增益耦合DFB激光器都能稳定地单纵模工作,而且具有高速、低啁啾的特性.本课题组用AlGaInAs/InP材料,采用增益耦合DFB结构,进行了单纵模激光器研发,并对器件特性进行了测试分析.     

In_(1-x)Ga_xAs_yP_(1-y)/InP DH化学腐蚀腔面激光器

用两相液相外延法生长 In_(1-x)Ga_xAs_yP_(1-y)/InP DH外延片,以 AZ1350i胶模掩蔽,在(001)DH片上,用Br_2:HBr:H_2O=1:25:50作腐蚀剂,沿<110>方向刻槽,研制成两种发射波长为1.35μm In_(1-x)Ga_xAs_yP_(1-y)/InP化学腐蚀腔面激光器.单面化学腐蚀腔面激光器的阈电流密度与常规解理腔面器件相比,未见增高.而双面化学腐蚀腔面激光器则有较高的阈电流密度.     

1.5μm波长范围的InGaAsP/InP分布反馈式激光器

<正> 日本KDD研究和发展实验室从理论上和实验上研究了1.5μm波长范围的InGaAsP/InP分布反馈式(DFB)激光器的激射特性。分析了5层DFB波导中波的传播,估算出结构参数对阈值条件的影响。在设计低阈值激光器及其激射波长方面进行了主要考虑。用液相外延方法制备了具有1.53μm发射主光栅的DFB隐埋异质结构激光器。在-20℃～58℃的温度范围内实现了CW工作。室温下的CW阈值电流低至50mA。在直流与500Mbit/s的伪随机脉冲电流     

半导体激光器阵列隔离槽的湿法腐蚀

研究了几种腐蚀液对半导体激光器阵列外延材料的腐蚀过程,其中HF(40 %) /CrO3 (33wt%)腐蚀液比较适合,用扫描电子显微镜(SEM)对其腐蚀情况进行了分析,并给出了利用这种腐蚀液进行腐蚀的半导体激光器阵列隔离槽的图像.通过调节HF/CrO3 腐蚀液的体积比(从0 0 2到0 2 ) ,确定了AlxGa1-xAs组分渐变材料的腐蚀条件(室温2 3℃,腐蚀时间4min)以及最佳配比(体积比为0 1) .利用这种腐蚀液得到的腐蚀图形可以满足激光器阵列的要求.     

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.     

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.