聚合物/SiO2混合波导2×2热光开关的制备与测试

利用聚合物材料SU-8作为芯层、聚合物材料PMMA作为上包层、无机材料SiO2作为下包层,设计并制备了一种有机/无机混合波导2×2定向耦合-马赫曾德尔(DC-MZI)热光开关。为了保证波导中的单模传输、减小模式辐射和衬底泄露损耗、缩短响应时间并降低器件功耗,对其结构参数做了优化。利用涂膜、湿法刻蚀等工艺制备了器件样品。在1 550nm波长下,器件的交叉态和直通态的驱动功率分别为0和7.8mW(开关功率为7.8mW),交叉态和直通态的两端口串扰分别为-9dB和-12.8dB。在方波驱动电压信号作用下,测得器件交叉端口的上升时间和下降时间分别为138μs和136μs,直通端口的上升时间和下降时间分别为63μs和140μs。制备的混合结构器件综合利用了芯层聚合物材料热光系数大、上/下缓冲层厚度均较小以及Si/SiO2导热系数大的优点,因此同时具备了较低的功耗和较快的响应时间,在低功耗、快速光通信系统中具有较好的应用前景。     

SiO2/聚合物Y分支波导型热光开关研究

为提高波分复用(WDM)光通信网中核心器件光开关 的响应速度,设计并制备了SiO₂/聚合物复合型 Y分支结构波导热光开关。器 件选择具有高热导率的SiO₂作为波导的下包层,低成本的聚甲基丙烯酸甲脂-甲基丙烯酸 环氧丙酯共聚物(P(MMA-GMA))作为芯层和上包层,利用束 传播法模拟和优化Y分支波导的设计,通过光刻、刻蚀和蒸发等传统半导体工艺进行器件制 备。实验测得开关插入损耗为12dB, 消光比为18dB,方波驱动的上升和下降响应时间均为200μs。实验结果表明,SiO₂/聚 合物复合波导结构可有效提高热场的扩散速度和折射率调节效率,减小开关的响应时间。     

掺杂LiYF_4:Er,Yb纳米晶的聚合物平面光波导放大器

采用高温热分解法合成了粒径约为10nm的LiYF4…Er,Yb纳米晶,将其掺杂入SU-8聚合物作为光波导放大器的有源层。以SiO2作为下包层,P(MMA-GMA)聚合物作为上包层,制备了LiYF4…Er,Yb纳米晶掺杂SU-8聚合物平面光波导放大器。当980nm波长抽运光功率为180mW时,在1535nm波长处获得了2.3dB/cm的相对增益率。     

乐甫波器件温度特性实验研究

研究了基于ST-90°X石英基片和SU-8波导层的乐甫波器件的温度特性。采用电极宽度控制单向单相(EWC/SPUDT)结构和铝电极,设计制作了具有单一模式控制功能和低插入损耗的150 MHz剪切型声表面波(SH-SAW)延迟线器件,并在其表面涂覆不同膜厚的SU-8声波导层构成系列乐甫波器件。由于SU-8波导层与石英基片温度系数的相反极性特性,SU-8膜厚直接影响到了乐甫波器件的温度特性。实验发现,覆盖不同膜厚的SU-8的乐甫波器件的中心频率随温度呈非线性变化,且在60~80℃内,SU-8膜厚为0.95μm时,其频率温度系数约为0.830×10-6/℃。     

低功耗有机/无机混合结构热光开关的研制

利用聚合物材料SU-8作为芯层、聚合物材料PMMA作为上包层和无机材料SiO2作为下包层,设计并研制了一种有机/无机混合结构的Mach-Zehnder干涉(MZI)热光(TO)开关。为了保证波导中的单模传输、减小模式辐射损耗和衬底泄露损耗、缩短响应时间并降低器件功耗,对其结构参数做了优化。利用化学气相沉积(CVD)、涂膜和湿法刻蚀等工艺制备了器件样品。在1 550nm工作波长下,器件的开和关状态的驱动功率分别为0和13mW(开关功率为13mW),开和关状态间的消光比为18.3dB。在方波驱动电压信号作用下,测得器件的上升和下降时间分别为126和134μs。与无机材料Si/SiO2和全聚合物材料研制的TO开关相比,本文研制的混合结构器件综合利用了芯层聚合物材料热光系数大、上/下缓冲层厚度均较小以及Si/SiO2导热系数大的优点,因此同时具备了较低的功耗和较快的响应时间,在光通信系统中具有较好的应用前景。     

基于两次衰减全反射结构的电光开关的研究

为了进一步提高电光开关的消光比,利用双面金属包覆波导激发的高阶导模是导波层折射率的灵敏函数这一特性,采用同一入射光束在波导中实现二次衰减全反射的方法,设计了一种快速响应的聚合物波导电光开关,并进行了理论分析和实验验证.得到该器件的消光比高达38dB,开关的响应时间低于110ns.结果表明,该电光开光器件具有动态范围大、驱动电压低、响应速率快、插入损耗小、器件稳定性能高以及制备工艺简单等诸多特点.这一结果对光互联、集成光路以及无线光通信等领域的应用是有帮助的.     

聚合物共面波导行波电极电光调制器

用聚合物材料BPAN-NT设计并初步成功制作了共面波导(CPW)行波电极电光调制器。用反应离子刻蚀(RIE)的方法制作脊波导,通过电晕极化使芯层有电光效应,利用电镀方法制作厚行波电极。对调制器的各项特性参数进行了测试,测得调制器的微波损耗系数0α=0.9 dB/cm.(GHz)1/2、在1.317μm波长上Vπ=250 V,由此算得芯层材料的电光系数3γ3=3.7 pm/V,同时测得消光比为13.49dB、插入损耗为18.6 dB,在8 GHz的微波频率上观察到了调制光信号,理论计算3 dB光调制带宽为43.77 GHz。     

基于悬浮波导的低功耗聚合物热光开关

设计制备了一种低功耗的马赫-曾德尔干涉仪(MZI)型聚合物热光开关器件,为降低开关的功耗,将器件加热区的调制臂波导设计成悬浮波导,从而抑制波导芯区处热量向硅衬底的扩散。模拟结果显示,相比于传统波导结构的热光开关,悬浮波导结构可以明显减少热扩散。利用半导体工艺成功制备了具有悬浮波导结构的热光开关器件,在1550 nm工作波长下,热光开关的功耗为9.3 mW,消光比为21 dB,开关的上升和下降时间分别为392μs和697μs。     

光子晶体电光调制和粗波分复用集成器件研究

提出了一种用于电光调制和粗波分复用的片上集成器件。该集成器件的电光调制器模块和粗波分复用器模块都是由硅基光子晶体波导和L3型谐振腔组成,两个模块间采用硅基光子晶体波导连接。该器件根据等离子体色散效应,采用L3型谐振腔和PN结实现了对波长的调制;根据微腔与波导的直接耦合理论,采用L3型谐振腔结构实现了滤波。利用基于三维时域有限差分法(3D-FDTD)的Lumerical软件对其进行仿真分析,结果表明该集成器件在工作波长1530 nm和1550 nm下均可以先完成各自的电光调制再进行双通道波长的复用。该器件在工作波长1530 nm和1550 nm下的插入损耗分别为0.70 dB和0.95 dB,消光比分别为20.97 dB和22.05 dB,调制深度均为0.99,信道串扰分别为-29.05 dB和-27.59 dB,器件尺寸仅为17.83μm×17.3μm×0.22μm。该集成器件结构紧凑,易于集成,可应用于高速大容量波分复用光通信系统。     

聚合物双环谐振滤波器的研究

设计了一种基于多模干涉(MMI)耦合输入/输出结构的跑道型双微环串联谐振滤波器,并采用紫外光敏聚合物材料SU-8作波导芯层,聚合物CYTOP为下包层,在硅基底上完成了器件的制备.器件的波导端面尺寸为2 μm×1 μm,与设计值相符,扫描电镜显示所制备的器件波导侧壁陡直度较高.直波导传输损耗的测试结果表明,在1550 nm波长,直波导传输损耗约为2.0 dB/cm.测试并获得了多模干涉结构和器件的通光及输出光谱图\.测试结果表明,MMI结构在较宽的波长范围内实现了接近50∶50的功分比,微环谐振滤波器的通光性能良好,实现了滤波功能,器件的自由光谱区FSR实际值约为0.94 nm,与设计参数值很接近.研究结果表明采用聚合物SU-8制备小波导尺寸微环谐振器的器件简便可行.     

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.     

Preparation and Characterization of TaN ALD Precursors

High purity organic-tantalum precursors for thin film ALD TaN were synthesized and characterized.Vapor pressure and thermal stability of these precursors were studied.From the vapor pressure analysis,it was found that TBTEMT has a higher vapor pressure than any other published liquid TaN precursor,including TBTDET,TAITMATA,and IPTDET.Thermal stability of the alkyl groups on the precursors was investigated using a 1H NMR technique.The results indicated that the tertbutylimino group is the most stable group on TBTDET and TBTEMT as compared to the dialkylamido groups.Thermal stability of TaN precursors decreased in the following order:TBTDET ＞ PDMAT ＞ TBTEMT.In conclusion,precursor vapor pressure and thermal stability were tuned by making slight variations in the ligand sphere around the metal center.