全光纤串联双环谐振器的滤波特性研究

基于传输矩阵法,分析了串联双环谐振滤波器传输特性,推导出了通路和下话路的传输函数表达式及最佳耦合条件。在忽略损耗情况下,计算分析了耦合系数和微环半径对滤波特性的影响,并进行了参数优化。计算结果表明:当串联双环半径分别为40μm和50μm、微环与直波导耦合系数为0.2时,滤波器的自由光谱范围能够达到22 nm且3 dB带宽仅为0.27 nm,从而能够实现在50 GHZ间隔的密集波分复用系统中仅对某一特定波长进行滤波。     

光子晶体波导定向耦合功分器的设计

将相互耦合的3平行光子晶体单模波导看成一个多模干涉系统,通过研究二维正方晶格光子晶体波导多模干涉的自映像效应,优化设计了一种新型1×2光子晶体波导定向耦合分束器,采用时域有限差分法对其传输特性进行模拟分析。设计过程中,根据多模干涉耦合区中周期出现的双重像的位置确定两个单模输出波导的位置,通过改变输出波导和耦合区连结的一个介质柱位置构成波导微腔结构,改变耦合区中的模场分布,实现模式匹配,从而明显减小分束器的反射损耗。计算结果表明,移动介质柱距离输出单模波导和多模波导连结处1.85a位置处时,对于波长为1.55μm的入射光,该分束器的透射率可高达99.04%。     

微纳光纤传输损耗测试及实验优化

对一种结合剪断法和后向散射法测量微纳光纤传输损耗的反射式剪断法进行了优化。通过增加分光耦合器和探测器,用气凝胶固定尾纤,消除了光源波动和尾纤摆动对实验测试的影响。利用该方法测量微纳光纤传输损耗与直径的关系,实验结果表明改进后的方法,测量结果更稳定。     

硅基微纳光子器件制备工艺问题及解决方案

讨论了硅基微纳光子器件制备过程中涉及的几个关键工艺问题,包括:电子束/光学光刻的电子束/光学邻近效应;纳米线光波导ICP-RIE刻蚀的侧壁粗糙问题;光栅及MOS绝缘栅氧化硅填充致密度问题.这些问题可影响器件的结构均匀性、波导传输损耗、光栅的散射损耗以及MOS绝缘栅的绝缘性能.在分析实验结果的基础上,提出了一些解决方案.     

硅基微纳光子器件制备工艺问题及解决方案

讨论了硅基微纳光子器件制备过程中涉及的几个关键工艺问题,包括:电子束/光学光刻的电子束/光学邻近效应;纳米线光波导ICP-RIE刻蚀的侧壁粗糙问题;光栅及MOS绝缘栅氧化硅填充致密度问题.这些问题可影响器件的结构均匀性、波导传输损耗、光栅的散射损耗以及MOS绝缘栅的绝缘性能.在分析实验结果的基础上,提出了一些解决方案.     

最佳端焦耦合法光波导传输损耗测量

根据最佳端焦耦合原理,建立了1.3μm波段光波导损耗测量系统,在测得系统附加透射损耗和G—PD响应特性曲线的基础上,对宽6μm的T_i扩散L_iNbO_3单模波导的传输损耗进行了测量评价,测量误差<±0.07dB/cm。     

基于SOI的2×2 MMI耦合器的设计

设计了一种可用于阵列波导光栅(AWG)解调集成微系统的绝缘体上硅(SOI)基2×2多模干涉(MMI)耦合器,用光束传播法(BPM)对MMI耦合器进行了模拟。耦合器输入/输出波导采用倒锥形,多模干涉区尺寸为6μm×57μm。在TE偏振中心波长为1.55μm时,器件附加损耗为0.46dB,不均匀性为0.06dB。在1.49～1.59μm波长范围内耦合器的附加损耗小于1.55dB。仿真结果表明所设计的2×2MMI耦合器体积小、附加损耗低、波长响应范围宽、分光均匀,符合片上集成系统的要求。     

带输入、输出端口的双芯光纤偏振分束器研究

双芯光纤偏振分束器是一类基于模式干涉的偏振分束器,是以双芯光纤作为定向耦合器,经过双芯光纤的耦合区域后实现的偏振选择性输出,因而其输入、输出端的形状和尺寸会影响光的输出功率及特性。基于椭圆双芯光纤,在分束器的输出消光比满足一定要求(大于20dB)的情况下,借助于RSOFT软件的Beamprop模块,研究双芯光纤偏振分束器输入、输出端口的形状和尺寸以及输入光的波长和线偏振角度对偏振选择特性的影响,及其可能的工作带宽和制作容差。结果表明,双芯光纤偏振分束器形状为S-Bend,X和Z方向的尺寸分别为40μm和4000μm的端口,输入光的工作带宽可以大于7.5nm,对应的耦合区长度较短,约为209.87mm。     

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.     

300K到4.2K下亚微米硅MOSFET的特性

我们在300K到4.2K温度范围内测量了亚微米硅MOSFET的特性,并画出了迁移率随温度的变化及载流子速度随纵向电场的变化(以温度为参数)曲线。发现500μm的器件在4.2K下的有效迁移率高达25000cm~2/Vs。而0.2μm的器件,由于高电场效应,其迁移率仅仅是800cm~2/Vs。我们画出迁移率随纵向电场的变化曲线,并发现,工作在0.1伏的器件,其弹道传播特性受到高电场的抑制。高电场效应也同样限制了亚微米GaAs FET的弹道传输效应。     

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.