亚波长金属光栅的凹槽深度对太赫兹伪表面等离子体影响

从理论上详细研究了一维亚波长金属光栅的凹槽深度对太赫兹伪表面等离子的影响。分别对一维标准亚波长金属光栅和缺陷亚波长金属光栅进行了研究。电场分布情况采用了COMSOL软件进行模拟。得到的结论是:对于一维标准亚波长金属光栅,沿金属光栅传播的表面等离子体取决于槽深度,较深的槽具有更强的束缚能力;对于具有缺陷的光栅结构,电场强度的分布特点取决于缺陷槽的深度,这归功于缺陷槽对光的反射和散射。基于这一理论研究,这两种不同的亚波长金属光栅结构能为太赫兹器件如波导、衰减器及滤波器发展提供新的途征。     

氧化锌单晶DFB半导体激光器的设计与分析

基于严格耦合波理论(RCWA)和介质平板波导理论,针对光通信中的1550 nm波长,设计了一种基于氧化锌(ZnO)单晶的分布反馈式(DFB)半导体激光器的光栅结构,分析了二维电场模式图以及激射波长线宽图,得到了光栅结构的变化对其单纵模传输的影响。仿真结果表明,当光栅的周期为489 nm,占空比为50%,光栅深度为400 nm时,全局电场能量达到了8.3×107 J,光谱线宽小于0.1 。该激光器具有很好的窄线宽输出以及波长选择特性。理论分析与仿真结果基本一致为后期进行该器件的制备提供了较好的参考。     

A Reconfigurable Optical Header Recognition System for Optical Packet Routing Applications

We demonstrate a reconfigurable all-optical packet processing system. The key device is a code-reconfigurable header decoder based on a fiber Bragg grating. The performance of the system is tested for different packet headers, and error-free operation is confirmed     

Bidirectional grating wavelength shifter with a broad-rangetunability by using a beam of uniform strength

Bidirectional chirp-free tuning in Bragg reflection wavelength by as much as 12.52 mm has been achieved based on the principle of a beam of uniform strength. The experimental results are in good agreement with the theoretical analysis. The tuning device is simple in configuration, low cost, and easy to operate, which can be used in numerous applications, such as tunable fiber grating lasers and reconfigurable wavelength add-drop multiplexers, etc     

CTaiJi--新的粗粒度可配置计算结构研究

首先阐述了粗粒度可配置计算结构在进行数据处理时的特点。依据此特点，提出了CTaiJi粗粒度可配置结构，详细说明了结构中各个组成部分。在系统结构中，将环形结构与网格结构相结合，PEZ（处理单元组合）非常适合处理循环、条件语句。能够将循环、条件及简单算术运算集中于同一PEZ中实现，利于系统实现实时配置和提高PE（处理单元）利用率。介绍了常用的数字信号处理算法在此粗粒度可配置结构上的映射。     

基于数字微镜器件的朗契检验

将传统的朗契检验原理、数字微镜器件和同位相探测方法结合起来,快速、较高精度地检测球面非球面透镜或大量值波像差.用数字微镜器件作为记录介质,代替普通的照相胶片,实时记录计算全息图.实验时先通过编制的程序,在计算机的控制下,在小数字微镜器件上显示一个光栅图像.然后将此小数字微镜器件放入朗契检验装置中.通过程序让光栅像移动与转动,并相应拍摄一系列朗契图像.最后进行分析计算.它的优点是代替普通的光学光栅和步进电机,并在测试中不要实际地移动与转动光栅.这样去除了因电机移动和光栅转动引起的测量误差,节省了时间.分析了数字微镜器件在光电测试中的应用特性.用同位相探测方法对球面进行了测量与计算,并进行了此球面的波面复原,给出了波像差的二维、三维图.     

Fabrication of (Pb,La)(Zr,Ti)O/sub 3/ thin-film arrayed waveguide grating

The design and fabrication of an 8-ch, 500 GHz-spacing arrayed waveguide grating on (Pb,La)(Zr,Ti)O₃ has been successfully achieved for the first time. An insertion loss of 22.1 dB, including a 10 dB coupling loss, and an adjacent crosstalk of -23.1 dB have been obtained. The device is expected to be monolithically integrated into high-speed optical switches to form integrated chips such as a reconfigurable add-drop multiplexer     

Field‐Switchable Broadband Polarizer Based on Reconfigurable Nanowire Assemblies

Reconfigurability is one of the most critical properties of nanophotonic systems and, consequently, methods for enabling a significant degree of functionality are highly sought after. However, dynamically responsive control in top‐down fabricated photonic structures often requires extreme conditions and yields moderate modulation capability. In sharp contrast to top‐down methods, directed self‐assembly of micro‐ and nanoparticles offers a distinct avenue for reconfigurable photonics. In the present work, gold nanowire lattices are formed via electric field directed assembly in order to take advantage of their collective optical properties. The lattices are reconfigured on‐demand between two different functional states, in the form of broadband polarizers. By selectively switching the electric field between two orthogonal electrode pairs, a maximum transmission contrast of ≈50% is observed in the near‐infrared regime. Moreover, the reconfigurable transmission spectra, which are highly dependent on the nanowire size and electric field conditions, are reversible. The demonstrated proof‐of‐concept nanowire lattice polarizer provides potential for electrically reconfigurable photonic devices such as ultra‐compact polarization components, electro‐optic switches, and on‐chip modulators.     

液晶显示器件的特殊电光特性分析

对液晶施加电场,液晶分子的排列会发生转变,其光学性质也会相应发生变化.本文采用多功能光栅光谱仪测试了不同电压下液晶显示器件透射率随波长的变化关系,采用光学多道分析器测试了液晶显示器件透射能量随波长的变化关系,对液晶显示器件的特殊电光特性进行了深入研究分析,发现紫外、可见光、红外波段其变化规律是不同的.     

基于氮化镓的通信波段可调DFB激光器的研究

为了利用悬空的周期可调光栅控制激光器的波长输出,采用了微机电系统技术中微驱动器与分布反馈激光器光栅相结合的结构,根据严格耦合波理论和介质平板波导理论,针对光通信的C波段,利用有限元软件COMSOL,建立了基于氮化镓的波长可调分布反馈激光器2维稳态模型。分析了1550nm处2维电场模式图以及激射波长线宽图,得到了激射波长与光栅周期的对应关系。结果表明,在光栅厚度、高度以及增益层厚度等结构参量一定的情况下,激射波长与光栅周期呈现与理论分析基本一致的似线性关系。该研究为该器件设计以及制备的后期工作开展提供了理论指导意义。     

基于液晶/聚合物光栅选频的高效率有机半导体激光器

报道了一种基于液晶/聚合物光栅选频的高效率有机半导体激光器的制备方法。首先在一片玻璃基板上旋涂有机半导体荧光薄膜MEH-PPV作为增益介质,然后在其上通过光场中的定域光聚合制备液晶/聚合物光栅,形成分布式反馈(DFB)有机半导体激光器。激光出射阈值0.32μJ/pulse,斜率转化效率高达7.8%,呈现良好的s偏振特性。采集了激光束的光斑,轮廓清晰,呈现扇形结构。通过改变光栅周期,实现了53.4nm激光出射范围。本工作为新型有机激光器的制备提供了有益的指导和借鉴意义。     

基于FPGA的数字发射机的设计

软件无线电的基本思想是以一个通用、标准、模块化的硬件平台为依托,通过软件编程来实现无线电台的各种功能,从基于硬件、面向用途的电台设计方法中解放出来.随着软件无线电技术的发展,数字调制发射机具有调制中心频率可调、频移可编程、调制方式可重组、调制码速率高、可以与编码器合并扩展功能强等很多优点,成为今后发射机的发展主流.本文...     

Reconfigurable Optical Add‐Drop Multiplexer Using a Polymer Integrated Photonic Lightwave Circuit

We have developed a fully functional reconfigurable optical add‐drop multiplexer (ROADM) switch module using a polymer integrated photonic lightwave circuit technology. The polymer variable optical attenuator (VOA) array and digital optical switch array are integrated into one polymer PLC chip and packaged to form a 10‐channel VOA integrated optical switch module. Four of these optical switch modules are used in the ROADM switch module to execute 40‐channel switching and power equalization. As a wavelength division multiplexer (WDM) filter device, two C‐band 40‐channel athermal arrayed waveguide grating WDMs are used in the ROADM module. Optical power monitoring of each channel is carried out using a 5% tap PD. A controller and firmware having the functions of a 40‐channel switch and VOA control, optical power monitoring, as well as TEC temperature control, and data communication interfaces are also developed in this study.     

A microfabricated metal grating oscillator for electric field detection

This letter proposes a novel design of a Micro Electro Mechanical System （MEMS） device featuring a metal grating vibratory mierostructure driven by electrostatic force to sense the spatial electric field. Due to the advantages in slide-film damping and large vibration amplitude, such a device makes atmospheric packaging a low-cost option for practical manufacture. In this letter, we present the operating principles and specifications, the design structure, as well as the finite element simulation. Computational analysis shows that our design obtains good results in device parameters setting, while its simplicity and low-cost features make it an attractive solution for applications.     

微纳光栅结构提高OLED器件性能的研究

有机发光二极管(organic light emitting diode, OLED)具有重量轻、功耗低、 响应时间快及具有柔性等特点,在平板显示 及固态照明等方面均显现出巨大的优势。为进一步提高OLED器件性能,本文利用ExpertOLED 仿真软 件对具有不同光栅结构的实际OLED器件进行仿真模拟,分析不同结构的微纳光栅对双金属电 极OLED 器件电致发光((electroluminescent,EL)光谱、发光视角及器件内部电场强度分布的影响。通过优化,得到增强 器件发光强度 和拓宽发光视角的微纳光栅结构。在不同的光栅周期下,改变光栅高度对器件的发光性能有 不同的影响。 调节发光层中分子偶极取向,优化器件内部电场强度分布,可进一步对器件的发光性能进行 优化,从而为实验上利用周期性微纳光栅结构提高OLED器件性能提供了具有价值的参考。     

光纤布喇格光栅电流传感器研究

本文实现了一种基于磁致伸缩棒在均匀磁场中的伸缩效应的光纤布喇格光栅电流传感器 .把光纤布喇格光栅牢固地沿纵向粘贴在一个置于多层漆包线绕成的螺线管中间的磁棒上 ,磁棒在螺线管中间部分的匀强磁场中随漆包线中电流的增加而沿纵向伸长 ,从而带动光栅在应变的作用下改变波长 .实验测得电流跟波长变化基本上成线性关系 ,波长的改变范围约 0 .9nm,其灵敏度约为 0 .0 0 1nm/ m A     

Improving Reconfigurable Systems Reliability by Combining Periodical Test and Redundancy Techniques: A Case Study

This paper revises and introduces to the field of reconfigurable computer systems, some traditional techniques used in the fields of fault-tolerance and testing of digital circuits. The target area is that of on-board spacecraft electronics, as this class of application is a good candidate for the use of reconfigurable computing technology. Fault tolerant strategies are used in order for the system to adapt itself to the severe conditions found in space. In addition, the paper describes some problems and possible solutions for the use of reconfigurable components, based on programmable logic, in space applications.     

Field-controllable liquid-crystal phase grating

A new liquid-crystal phase-grating mode has been found. The grating is formed by the application of a spatially periodic electric field to a uniformly aligned liquid-crystal layer with dielectric and optical anisotropy. The fundamental diffraction characteristics of this liquid-crystal phase grating were measured by using a Schlieren optical system, and analyzed based on Fraunhofer diffraction theory with the assumption that the refractive indices vary periodically in the liquid-crystal layer. The incident light is diffracted under the electric field in particular directions determined by the spatial frequency of the periodic electrode, and the intensity of the diffracted light increases abruptly or gradually above the threshold depending on the cell thickness. The applicability of this liquid-crystal phase grating to a light valve in a projection display system is also considered.     

一种数字光栅无掩模光刻对准方法

针对数字微反射镜装置(DMD)无掩模光刻系统,提出并研究了一种数字光栅无掩模光刻对准方法,将硅片的微位移放大显示在数字光栅与硅片物理光栅叠加产生的叠栅条纹中。建立了基于DMD的数字光栅无掩模光刻对准模型,设计了对准标记以及具体的实现方案,并对模型进行了数值仿真和初步的实验验证。结果表明,采用频率可变、图像干净、具有良好周期性结构的数字光栅代替传统的真实掩模光栅,真正实现了零掩模成本;并且采用变频率数字光栅可以扩大测量范围,减小位移测量误差。最终可以实现深亚微米的对准精度,满足目前无掩模光刻对准精度的要求。     

Field distributions inside fiber gratings

We have developed a technique to calculate the electric field distributions of a light wave propagating through a fiber grating (FG). The technique is based on a transfer matrix method developed for electric field calculations in multilayer thin films. We apply this method to several FG structures of practical interest in optical fiber networks based on wavelength-division multiplexing. Two-dimensional plots of the average internal power versus the distance along the grating axis and light frequency are presented. This representation allows a better understanding of the macroscopic behavior of these structures