光通信C波段硅基导模共振窄带滤波器的模拟

结合严格耦合波理论和遗传算法对C波段硅基导模共振滤波器进行了模拟分析.从模拟结果出发详细讨论了光栅周期、填充因子、光栅深度和入射角度对滤波器反射特性的影响.导模共振对光栅周期、填充因子、光栅深度和入射角度都有很高的敏感性,利用这一特点可以设计性能优异的硅基滤波器件.导模共振滤波器的共振波长峰值反射率达到了98.9%,峰值半高宽小于密集渡分复用(DWDM)O.8 nm的要求.

Abstract：

Simulated are silicon-based guided-mode resonant grating filters with narrow bandwidth for C-band optical communication.The effects of the characteristics of grating period,fill factor,the grating depth,the thickness of SiO_2 layer and incident angle on the reflection mechanisms of the filters are analyzed in detail based on the simulation results.Guided-mode resonant effect is very sensitive to such characteristics,which can be used to optimize silicon-based filters.The reflectance of the resonant wavelength of this filter reaches 98.9%,and the FWHM (full width at half maximum) is less than 0.8 nm limited by the DWDM (dense wavelength division multiplication) system.     

一种多孔硅基导模共振滤波器的研究

提出了一种基于多孔硅的光栅导模共振滤波器,采用严格的耦合波理论分析方法,进行数值仿真并分析了多孔硅基导模共振滤波器的反射光谱特性.同时设计了工作在1550nm波长的窄带多孔硅硅基光栅滤波器的结构参数.研究结果表明,此滤波器具有非常高的反射率峰值,和边带抑制较高且带宽较窄的反射谱,是一种性能优异的光通信硅基滤波器件.     

光学层析成像用1.7μm波段增益谱和宽带光源实验研究

1.7μm波段光源在光学相干层析成像(OCT)系统中可以减少组织散射和吸收损耗,从而增加成像深度。提出以放大自发辐射(ASE)光源抽运长度为300m的高非线性光纤和长度为10km的色散位移光纤产生连续光源。其中,后置于ASE抽运源的可调谐滤波器调节连续光源的峰值波长和功率,所得光源经过掺铒光纤吸收整形后得到峰值波长为1675nm,10dB谱宽约为75nm的连续光源。为了在不提高抽运功率的情况下提高OCT信噪比,增加了萨尼亚克滤波器,得到了周期为14nm的近似多波长宽带光源。实验结果表明,该结构可实现1.7μm波段的宽带光源,实验分析结果为OCT新型光源及1.7μm波段光纤激光器提供参考。     

基于多波段混合气体吸收谱线的波长标定方法研究

为实现光纤扫描光源宽调谐范围内输出波长的高精度标定,提出了一种基于多波段混合气体吸收谱线的波长标定方法。采用分段阈值二阶导极值法和洛伦兹线型拟合法从混合气体吸收光谱中提取多条谱线中心位置,以其波长和驱动电压为参考点对Fabry-Perot(F-P)可调谐滤波器的迟滞非线性特性进行二次多项式拟合标定。将C2H2在C波段的吸收带与CO2在L波段的吸收带相结合,选取了21条C2H2谱线和16条CO2谱线作为波长参考。将本方法用于C+L波段的光纤光栅(FBG)波长解调,在0~60℃范围内波长拟合标准差小于3.3pm,线性相关系数大于0.999 8,系统稳定性误差小于2.6pm。     

入射角调谐的三基色导模共振滤光片

介绍一种入射角调谐红绿蓝三基色导模共振滤光片(GMRF)的实现方法。利用严格耦合波理论(RCWA)分析入射角对导模共振滤光片反射光谱的影响,用TM偏振波在斜入射下得到两个不同位置的共振峰,通过调节入射角,使两个共振峰分别落在可见光波段和红外波段,并通过调整角度实现对可将光波段滤波波长的调谐。通过对参数的优化、调整,设计并制作了周期为544 nm的红、绿、蓝三基色导模共振彩色滤光片,结果显示该结构在26.8°、39.6°、46.0°入射角得到了良好的红、绿、蓝三基色,效率均在80%左右,半峰全宽约为5 nm。当其作为蓝、绿两色滤光片工作时,与传统亚波长导模共振结构相比,其周期相对较长,从而大大降低光栅制作难度。实验结果实现导模共振结构在彩色滤光片方面的应用,并对大周期导模共振器件的制作提供了积极的指导。     

基于氮化铝的1310nm波段可调DFB激光器的设计

依据严格耦合波理论和介质平板波导理论,基于MEMS(微机电系统)技术,利用周期可调谐的布拉格光栅设计了一种基于氮化铝的波长可调DFB-LD(分布反馈激光器)。采用梳齿状驱动器驱动光栅动态调节,并利用有限元软件COMSOL对其在1 310nm波段进行模拟仿真。对激光器电场模式图进行分析,确定了DFB-LD的光栅结构参数。分析表明,激光器输出波长与光栅周期呈线性关系,且一个光栅周期对应多个不同的光栅高度值。在小于模式截止光栅高度的情况下呈20nm周期性分布。依据光栅周期和激射波长的关系,提出了制作1 290~1 330nm波段可调激光器的可能性。     

一种高性能环形可调谐光纤光栅激光器研究

研制了一种新型的高性能环形可调谐光纤光栅激光器。该激光器使用980nm LD作为泵浦源,使用长度为10. 8m的新型增益平坦掺铒光纤作为增益介质,采用可调谐光纤光栅滤波器进行波长调谐,调谐范围可达41nm (1528nm～1569nm) ,中心波长可精确调谐到C波段指定的ITU - T标准中心波长处, 3dB 带宽< 0. 08nm, 25dB带宽< 0. 2nm,波长稳定性优于0. 01nm,边模抑制比> 60dB。最大输出功率46. 94mW,功率稳定性优于±0. 02dB,阈值泵浦功率7. 3mW,斜率效率为39. 75%。并分析了不同腔长、不同输出耦合比对输出功率的影响。     

利用AOTF的可调谐光纤激光器的特性研究

提出了一种新型的可调谐光纤激光器 ,其谐振腔是由声光可调谐波长滤波器 (AOTF)和掺铒光纤构成的Fabry Perot腔。该激光器具有调谐方便 ,调谐速度快和调谐范围大的优点。在忽略激发态吸收和放大的自发辐射情况下 ,对该激光器的线宽和调谐特性以及阈值抽运功率和斜率效率进行了理论计算。在中心工作波长 15 5 0nm处 ,得到输出峰值的半极大值线宽 (FWHM)约为 0 2 6nm ,并且在 15 5 0nm附近 ,声波频率每改变 1MHz所调谐的峰值波长间隔约为 8 95nm。理论上 ,调谐范围只受掺铒光纤增益和滤波器带宽的限制。计算结果表明 ,该激光器的阈值抽运功率和斜率效率分别为 0 795mW和 15 15 %。     

全光纤转动拉曼激光雷达的光纤光栅分光技术研究?

设计了一款由可见光波段的光纤布喇格光栅和光纤耦合器构建的全光纤转动拉曼激光雷达分光系统。利用相位掩模板侧向成功刻写530 nm波段光纤布喇格光栅,并初步测试其透射谱和反射谱性能。为提高光纤光栅中心波长与大气氮气分子转动拉曼谱线的匹配特性,利用悬臂梁设计高调谐灵敏度的调谐系统。实验结果表明,成功研制的可见光波段光纤布喇格光栅其反射率约为95%,带宽约为0.3 nm,应力调谐系统可实现± 0.6 nm范围18 pm/r 的波长调谐。     

瓦级100nm可调谐中红外Er∶ZBLAN光纤激光器

报道了输出功率为瓦级,调谐范围超过100 nm的中红外2.8 mm波段光纤激光器。采用中心波长为975 nm半导体激光器抽运高掺铒氟化物(Er:ZBLAN)双包层光纤,以闪耀光栅为调谐元件,室温下实现了功率大于1 W、宽范围可调谐的2.8 mm波段光纤激光输出,最大调谐范围达122 nm。激光器在波长2.831 mm处输出功率为1.02 W,斜率效率为21.6%。     

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.     

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.