聚合物光栅光波导器件的微复制技术

采用纳米压印微复制技术方法,研制了一种新型的聚合物柔性光栅光波导敏感器件,该器件可用于介入式医用导管的微弯挠曲监测或类似场合的微变形监测.重点阐述了聚合物柔性光栅光波导器件的微复制模具和器件微复制的工艺方法,并对制备工艺技术中的关键技术问题进行了讨论,讨论了测试光纤耦合一体化光栅波导器件的工艺方法.最后利用硅微模具和紫外固化介质材料,成功制备出了截面尺寸为4 μm×20 μm、光栅周期为0.75 μm的聚合物柔性光栅光波导器件.     

The evolution of solitons in coupled resonator optical waveguides and photonic-crystal waveguides

We successfully used the tight binding theory to derive the extended discrete nonlinear Schrödinger equation to describe the soliton propagation and to obtain the soliton propagation criteria (SPC) in the nonlinear photonic-crystal waveguides (PCWs) and coupled resonant optical waveguides (CROWs) containing Kerr media. From these criteria, we obtain the soliton-propagating region of CROWs in different numbers of separated rods and strengths of self-phase modulation (SPM). The defined soliton-propagating regions coincide with the regions of modulation instability in the CROWs. In the PCWs, the positive Kerr coefficient medium needs to be added to support the pulse propagation in low frequency or low wave vector region of the dispersion curve; while negative Kerr effect is for high frequency case. Due to the linear combination of various cosine harmonic functions in the dispersion relations of both CROWs and PCWs, the pulse broadening which is mainly caused by the third-order dispersion at SPC is the lowest at the boundary of dispersion curves. However, due to the different magnitudes of coupling coefficients in CROWs and PCWs, the group velocity, dispersion and strength of SPM in CROWs are all smaller than those in PCWs.     

Numerical modeling of multimode doped optical waveguides

In recent years, several papers have addressed the modeling of wave propagation through doped optical fibers and micrometer waveguides. These devices exhibit gain and are essential for optical processing applications.Recently, an efficient self-consistent numerical scheme for modeling short doped optical waveguides was published in the literature. Given an input pump and signal beams, a set of three-level rate equations are solved for modeling the interaction between the optical waves and the active doped media. This result is used to compute the permittivity profile accurately, which in turn is used to compute, by means of a finite element code, the associated modes for the pump and signal beams. Next, these updated beams are used in the solution of the rate equations and so on, until a self-consistent convergence is reached. However, this scheme only takes into account monomode waveguides.On the other contrary, in order to obtain higher gain levels, highly confined modes might need to be launched—the pump in particular—and consequently, higher order modes may be excited. In this work we extend the self-consistent scheme for multimode waveguides, therefore, substantially enlarging its range of practical applications. Comparisons with other numerical schemes and experimental results, confirm the efficiency and accuracy of our model.     

Transients in beam position control systems for optical waveguides

Beam position transients in self-aligning beam waveguides are studied. The control system senses the beam position, rn, at each lens and introduces a corrective termC_{n-1}to the transverse position of the preceding lens. The Laplace transform of the beam position at thenth lens, for the case of a general control functionH(s), relating rnandC_{n-1}, is found. The special case of a confocal guide, where the control function is an integrator with gainH(s) = g/s, results in a time dependence of the beam positions at the lenses, equal to the product of a decaying exponential and Laguerre polynomials. The case where the control functionH(s)represents a second-order system has been simulated on a digital computer. The results show that overshoot can be controlled by increasing the damping term inH(s).     

Interaction of guided light in rib polymer waveguides with dielectrophoretically controlled nanoparticles

This work demonstrates an optofluidic system, where dielectrophoretically controlled suspended nanoparticles are used to manipulate the properties of an optical waveguide. This optofluidic device is composed of a multimode polymeric rib waveguide and a microfluidic channel as its upper cladding. This channel integrates dielectrophoretic (DEP) microelectrodes and is infiltrated with suspended silica and tungsten trioxide nanoparticles. By applying electrical signals with various intensities and frequencies to the DEP microelectrodes, the nanoparticles can be concentrated close to the waveguide surface significantly altering the optical properties in this region. Depending on the particle refractive indices, concentrations, positions and dimensions, the light remains confined or is scattered into the surrounding media in the microfluidic channel.     

Generating multi-mode entangled coherent W and GHZ states via optical system based fusion mechanism

Fusion technology has been demonstrated to be a good method for generating a large-scale entangled coherent W or GHZ state from two small ones in QED system. It is of importance to study how to fuse small-scale entangled coherent W or GHZ states via optical system. In this paper, we present a scheme for generating larger entangled coherent W or GHZ state in an optical system by virtue of fusion technology. The key fusion mechanism is realized by photon detectors and a Mach–Zehnder interferometer with its two arms immersed in Kerr media, by which an n-mode entangled coherent W state and an m-mode entangled coherent W state can be probabilistically fused into an (\(n+m-2\))-mode entangled coherent W state. This fusion scheme applies to entangled coherent GHZ state too but with a unit probability of success. Feasibility analysis indicates that our fusion scheme may be realized with current experimental technology. Large-scale entangled coherent W and GHZ states may find new applications in quantum communication.     

Thermal-deformation analysis of a polymer micro-mirror optical device

This paper analyzes the thermal deformation in SU-8 polymer materials when subjected to different fabricating parameters and exposed to a high power light source for long durations for 45° micro-mirror applications. By experimentally optimizing the fabrication process, new fabricating technologies for micro-optical components can be developed. During the fabrication process, a polymer-based material is subjected to different soft bake, post exposure bake (PEB), hard baking temperatures; also, the baking times and exposure dosages were varied. Any of these variables can change the thermal stability of the material’s bonding energy and dynamic molecular behavior. There have not been many studies on the thermal deformation of a micro-mirror structure. A thermal dilatometer DIL-402C was used in this study to measure the thermal stability and determine changes in the material phase of SU-8 material. After optimizing the process parameters and finding that the inclined surface roughness was 49 nm, the thermal deformation was found to be 25 ppm (at 100°C).     

Fabrication of polymer micro-tip by optical lensing technique

Fabrication of polymer micro-tips using SU-8 negative photoresist for bio-applications is reported. The SU-8 processing technology and isotropic glass etching process have been developed and utilized to fabricate micro-tips on glass substrate by applying optical lensing effect during photolithography. Experimentally, micro-tips of 25?μm base diameter, ~1?μm tip diameter, and ~250?μm height, have been demonstrated.     

A two-dimensional optical cross-connect with integrated waveguides and surface micromachined crossbar switches

The design, fabrication and test results of an all-optical cross-connect, which uses electrostatically actuated micromechanical digital mirrors to steer optical signals in a network of planar waveguides, are presented. The substrate consists of a network of spliced planar waveguides on silica substrates. The switches, located at the waveguide intersections, are formed with an electroplated T-structure consisting of a horizontal perforated square plate suspended by four elastic beams. When operated, the horizontal plate is pulled up making the mirror move out of the optical path thus steering the beam. An 8×8 switch array has been fabricated and tested. Actuation and relaxation switching times near 3 ms have been demonstrated with an actuation voltage of 120 V. The optical insertion loss for the array typically varied from 2.3 dB for a single trench in the optical path (shortest optical path) to 8 dB for 15 trenches in the optical path (longest optical path).     

基于软件无线电的多模式调制解调技术

全文介绍了新型的软件无线电技术及基于软件无线电的多模式调制解调技术,并对该技术进行理论探讨和设计实现。     

支持多种并行程序设计模式的可移植并行调试器设计与实现

MPDG是为高性能并行巨型机系统设计的调试工具,其设计指导思想是：1．采用Client/Server结构,实现系统的可移植性,具体表现为将用户界面,并行调试管理与调试监控服务分离,调试监控采用目标系统支持的调试器;2．以同一的使用方式支持多种并行程序设计模式应用,针对共享内存的并行目标应用（如OpenMP程序)和基．于水息传递的分布式目标应用（如PVM或MPI程序）,提供风格完全一致的调试手段;3．实现图形用户界面,MPDG的GUI分为3级,即主界面,进程集,单个进程,进程集控制特别适合具有相同执行流和用户视图的并行进程的调试。     

Effectiveness of Taguchi method for the optimization of narrowband optical filters based on grating waveguides

Microsystem Technologies - This work is an illustration of a narrowband optical filter device based on cladding modulated grating waveguide for enhancing the device performance in terms of...     

Metallo-porphyrin zinc as gas sensitive material for colorimetric gas sensors on planar optical waveguides

The presented work focuses on the investigations of a metallo-porphyrin and its gasochromic behavior to different gases. Gasochromic materials change their color while they are exposed to a certain gas. So they offer the possibility to develop highly selective chemical gas sensors and gas sensing systems. The focus of this work is the characterization of the metallo-porphyrin 5, 10, 15, 20-tetraphenylporphyrin-zinc (ZnTPP). Nonetheless, there is a wide range of other possible metallo-porphyrins. When embedded into a polymeric matrix (PVC) a color change to the toxic gas NO₂ can be detected. To develop a stand-alone gas sensor, the porphyrin/PVC matrix is deposited onto a planar optical waveguide. The color change of the porphyrin dye can be detected in the evanescent field of the optical waveguide. Therefore, the light of a high power LED is coupled into the waveguide. The color change of the porphyrin is detectable with photodiodes as a variation of the out-coupled light intensity. The sensor shows no unwished sensitivities to CO₂ and CO and only low to NH₃. NO₂ is detectable with a resolution of 1?ppm.     

Calculation of optical properties of aluminum

In the present work, optical properties of electronic Fermi gas of aluminum are considered at any temperature (T ≥ ɛ _F ). The dependences of inductivity are obtained from the solution of the quantum kinetic equation expressions for temperature and frequency. With the help of Fennel’s formula, the frequency and temperature dependences of the reflectivity of an irradiated surface and volume factor of absorption are defined.     

Optimisation of a polymer membrane used in optical oxygen sensing

A method for detection of viable cells utilises a sensor based on the optical measurement of oxygen consuming by cells. Changes in the oxygen level were measured via quenching of the fluorescence of an oxygen-sensitive fluorophor (Ru(dpp)₃Cl₂). The fluorescence lifetime changing was measured in accord with Stern–Volmer equation, using a phase-shift method. The fluorophor was embedded into a polysulfone membrane that is in contact with the cell medium. The sensitivity of oxygen sensor depends on behaviour of polysulfone membrane. Manufacturing method, type of polysulfone and concentration of fluorophor can also change this behaviour. These parameters were explored to obtain the optimum analytical performance, and the optimum sensitive membrane was chosen for 3 mmol/l concentration of fluorophor, when a linear plot was obtained with R=0.99987 for a sensitivity of 12.11±0.11 mV/% O₂ (n=5).     

多模式系统的测试顺序优化

研究了多模式系统的测试顺序优化问题。基于不同模式下测试与故障之间的依赖关系,结合系统故障的先验概率、可用测试的成本以及不同模式的转换费用,构造了该问题的数学描述模型。基于已有的搜索算法提出了一种准多步前向搜索算法,该算法以信息增益为启发策略,可自动获取平均测试费用最少、且能快速实现系统故障检测与隔离的优化测试顺序。最后实例验证了该算法的正确性,证明该算法可解决实际问题。     

基于FPGA的数字基带多模雷达信号源设计

多模雷达信号源可用于电子侦察设备的性能测试和生成式欺骗干扰信号的产生。针对一种基于现场可编程门阵列(FPGA)的多模雷达数字信号源系统设计进行了研究,并将关键的多模雷达信号产生模块封装为具有AXI总线结构的IP核,其灵活性高、重用性强,能够输出多种常规雷达信号和低截获概率(LPI)雷达信号。首先对DDS产生信号的原理进行了研究,然后根据雷达信号的调制方式设计了多模雷达信号源的顶层结构。在Xilinx Zynq-7xc7z010clg400上进行编程实现。测试结果表明,本设计占用资源少,且信号的最高输出速率可达500 MS/s。     

超细AlN填充环氧树脂热性能研究

采用钛酸酯偶联剂对超细氮化铝(AIN)粉末改性,通过高速机械搅拌和超声波分散相结合的方法,在高真空条件下,制得NTC热敏电阻器用AIN改性环氧树脂(EP)灌封材料。通过对材料的性能测试表明:改性后的EP材料热膨胀系数明显下降,填料高质量分数时下降达到3.05×10-5/℃;导热系数明显提高,由EP的0.28W/(m.K)提高到1.07W/(m.K),提高了2.8倍;DMA分析发现:偶联剂质量分数为3%时,填料与基体的界面结合能比较好,其样品性能最好。     

超细AIN填充环氧树脂热性能研究

采用钛酸酯偶联剂对超细氮化铝(AIN)粉末改性,通过高速机械搅拌和超声波分散相结合的方法,在高真空条件下,制得NTC热敏电阻器用AIN改性环氧树脂(EP)灌封材料。通过对材料的性能测试表明:改性后的EP材料热膨胀系数明显下降,填料高质量分数时下降达到3.05×10-5/℃;导热系数明显提高,由EP的0.28W/(m.K)提高到1.07W/(m.K),提高了2.8倍;DMA分析发现:偶联剂质量分数为3%时,填料与基体的界面结合能比较好,其样品性能最好。     

Estimation of optical properties of nearshore water

Most of the existing satellite sensors lack the spectral capabilities to discriminate phytoplankton pigments in water bodies. New satellite sensors (i.e. SeaWIFS) and future sensors on board EOS withnarrow bandwidths will provide fine spectral resolution necessary to distinguish optical properties of nearshore waters provided sea data are available. This will enable spaceborne water color sensors to discriminate bloom forming phytoplankton species. The objective was to develop a library of absorption spectra for the most common phytoplankton species found within the Hudson/Raritan Estuary and coastal waters of New Jersey. Both culture-grown and field samples of phytoplankton were concentrated and analyzedusing chemical and spectrometric techniques. Using spectral derivative and polynomial regression analysis, it was possible to identify wavelengths that could be used to characterize the pigment compositions of phytoplankton species in the estuary.