宽带偏振不灵敏InGaAs半导体光放大器

采用压应变InGaAs量子阱和张应变InGaAs准体材料交替混合的有源结构，研制了宽带偏振不灵敏的半导体光放大器．此放大器在100～250mA的工作电流范围内，获得了大于70nm的3dB光带宽；在0～250mA工作电流和3dB光带宽波长范围内，偏振灵敏度小于1dB．对于1.55μm的信号光，在200mA的注入电流下获得了15.6dB的光纤到光纤的增益、小于0.7dB的偏振灵敏度和4.2dBm的饱和输出功率．     

宽带偏振不灵敏InGaAs半导体光放大器

采用压应变InGaAs量子阱和张应变InGaAs准体材料交替混合的有源结构,研制了宽带偏振不灵敏的半导体光放大器.此放大器在100～250mA的工作电流范围内,获得了大于70nm的3dB光带宽;在0～250mA工作电流和3dB光带宽波长范围内,偏振灵敏度小于1dB.对于1.55μm的信号光,在200mA的注入电流下获得了15.6dB的光纤到光纤的增益、小于0.7dB的偏振灵敏度和4.2dBm的饱和输出功率.     

渐变应变偏振不灵敏半导体光学放大器

采用渐变应变有源区结构,制备出偏振不灵敏半导体光学放大器,工作电流在60～160mA范围内,其3dB带宽范围不小于35nm,偏振不灵敏度小于0.35dB,自发发射出光功率为0.18～3.9mW.     

渐变应变偏振不灵敏半导体光学放大器

采用渐变应变有源区结构,制备出偏振不灵敏半导体光学放大器,工作电流在60～160mA范围内,其3dB带宽范围不小于35nm,偏振不灵敏度小于0.35dB,自发发射出光功率为0.18～3.9mW.     

适于InGaAsP光放大器偏振不灵敏的增益介质

研制了适于InGaAsP光放大器偏振不灵敏的增益介质 ,采用有源区内交替的张应变和压应变排列的混合应变量子阱结构 ,器件做成带有倾角的扇形。实验中发现该结构既抑制了激射又改善了器件的偏振灵敏性 ,实现了偏振灵敏度小于 0 5dB ,10 0mA偏置时可达 0 1dB。在较大的电流范围内 ,峰的半高全宽 (FWHM)为 4 0nm。     

1.3μm高增益偏振无关应变量子阱半导体光放大器

采用低压金属有机化学气相外延法 (LP MOVPE)生长并制作了 1 3μm脊型波导结构偏振无关半导体光放大器 (SOA) ,有源区为基于四个压应变量子阱和三个张应变量子阱交替生长的混合应变量子阱 (4C3T)结构 ,压应变阱宽为 6nm ,应变量 1 0 % ,张应变阱宽为 11nm ,应变量 - 0 95 % ;器件制作成 7°斜腔结构以有效抑制腔面反射。半导体光放大器腔面蒸镀Ti3 O5/Al2 O3 减反 (AR)膜以进一步降低腔面剩余反射率至 3× 10 -4以下 ;在 2 0 0mA驱动电流下 ,光放大器放大的自发辐射 (ASE)谱的 3dB带宽大于 5 0nm ,光谱波动小于 0 4dB ,半导体光放大器管芯的小信号增益近 30dB ,在 12 80～ 1340nm波长范围内偏振灵敏度小于 0 6dB ,饱和输出功率大于 10dBm ,噪声指数 (NF)为 7 5dB。     

高增益偏振不灵敏InGaAs/InP体材料半导体光放大器

采用三元InGaAs体材料为有源区，通过直接在InGaAs体材料中引入0．20％张应变来加强TM模的增益，研制了一种适合于作波长变换器的偏振不灵敏半导体光放大器(SOA)。在低压金属有机化学气相外延(LPMOVPE)的过程中，只需调节三甲基Ga的源流量便可获得所要求的张应变量。制作的半导体光放大器在200mA的注入电流下，获得了50nm宽的3dB光带宽和小于0．5dB的增益抖动；重要的是，半导体光放大器能在较大的电流和波长范围里实现小于1．1dB的偏振灵敏度。对于1．55gm波长的信号光，在200mA的偏置下，其偏振灵敏度小于1dB，同时获得了大于14dB光纤到光纤的增益，3dBm的饱和输出功率和大于30dB的芯片增益。用作波长变换器，可获得较高的波长变换效率。进一步提高半导体光放大器与光纤的耦合效率，可得到性能更佳的半导体光放大器。     

1550 nm偏振不灵敏半导体光放大器的研制

研制了有源区为InGaAs张应变体材料的1.55 μm偏振不灵敏半导体光放大器(SOA).采用束传播法计算了偏离镜面垂直方向7.的埋层波导结构模式场分布,并用平面波展开法设计了多层抗反射膜,在TE模和TM模反射率同时小于10-4时膜厚允许误差为3%.对放大自发发射谱(ASE)和增益谱的分析表明,他们具有基本一致的偏振灵敏度.对一腔长800 μm的SOA在注入电流250 mA时,测量得出TE模和TM模的ASE谱偏振灵敏度小于0.5 dB,增益谱3 dB带宽为63 nm,1 550 nm处光纤到光纤增益为11.9 dB,3 dB饱和输出功率为5.6 dB,在1 570 nm处的噪声指数为7.8 dB.而一腔长1 000μm SOA耦合封装后得到的最大增益为15 dB.     

低偏振灵敏度半导体光放大器

报道了基于混合应变量子阱材料的半导体光放大器 (SOA)。利用张应变量子阱加强了TM模的增益 ,使之接近TE模的增益 ,从而使SOA的偏振灵敏度大为降低。在 150mA的偏置下 ,获得了 2 4dB的小信号增益和 1dB的偏振灵敏度。     

直接耦合半导体光放大器的噪声特性

研究了直接耦合混合应变量子阱半导体光放大器(SOA)的噪声特性.实验中测定SOA在130 mA偏置电流下的噪声指数为7.7 dB,表明应变量子阱结构改善了SOA的噪声性能.理论分析指出,通过消除SOA的剩余反射,其噪声性能可以得到进一步改善.     

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.