Kelcy Allwein, Defense Intelligence Agency, Kelcy.Allwein@dia.mil Elisabeth Andre, University of Augsburg, andre@informatik.uni-augsburg.de Thom Blum, Muscle Fish, a division of Audible Magic thom@musclefish.com Shih-Fu Chang, Columbia University, sfchang@ee.columbia.edu Bruce Croft, University of Massachusetts, croft@cs.umass.edu Alex Hauptmann, Carnegie Mellon University, alex+@cs.cmu.edu Mark Maybury (chair) The MITRE Corporation, maybury@mitre.org Andy Merlino, Pixel Forensics, amerlino@pixelforensics.com Ram Nevatia, University of Southern California, nevatia@iris.usc.edu Prem Natarajan, BBN, prem@bbn.com Kirby Plessas, Open Source Works, kirbyp@open-source-works.org David Palmer, Virage, dpalmer@virage.com Mubarak Shah, University of Central Florida, shah@cs.ucf.edu Rohini K. Shrihari, SUNY Buffalo, rohini@cedar.buffalo.edu Oliviero Stock, Istituto per la Ricerca Scientifica e Tecnologica, stock@fbk.eu John Smith, IBM T. J. Watson Research Center, jsmith@us.ibm.com Rick Steinheiser, DNI/Open Source Center, RickS@rccb.osis.gov Sharon Walter (co-chair) AFRL, Rome NY, Sharon.Walter@rl.af.mil
Long-term stability of embedded passives is very important issue. To determine this matter an aging process can be used, where test samples are exposed to environmental conditions. Objective of this research was analyzing reliability of thin-film resistors based on Ohmega-Ply® technology. Resistive material was a nickel-phosphorus (Ni-P) alloy (with sheet resistance 25 ¿/sq or 100 ¿/sq) on FR-4 substrate. A number of variables were considered in this study (sheet resistance, geometry of resistor, type of cladding, laser trimming, pulse stress and environmental conditions). Two different accelerated ageing processes ¿ Ex-Situ (samples exposed to elevated temperature and/or relative humidity but resistance measurements made at room temperature) and In-Situ (resistance of test samples performed directly at the ageing conditions) were carried out to perform long-term behavior analysis. The results revealed a significant influence of thickness of resistor, type of cladding and temperature on stability of investigated structures. Signification of other factors was negligible.
In this work photocatalytic activity of transparent TiO2 coatings doped with Tb was described. Thin films were performed by high energy reactive magnetron sputtering process. During deposition, particles were sputtered from metallic Ti and Ti-Tb targets in oxygen reactive plasma. The properties of thin films were characterized by several methods. Influence of Tb-dopant on the structure and diversification of the surface was investigated by X-ray Diffraction and Atomic Force Microscopy, respectively. Optical properties of manufactured films, especially transparency level and adsorption edge, were determined based on optical transmission measurements. Photocatalytic activity of TiO2:Tb thin films was determined based on phenol decomposition reactions under UV-Vis light exposure. The rate of phenol decomposition was determined based on absorption measurements. The results have shown that all manufactured films were nanocrystalline and photocatalytically active. Doping with terbium meaningfully increased the activity of as-deposited films. In this paper dependences between structure type of the TiO2-matrix, crystallites size, roughness of the thin film surface and photocatalytic activity of TiO2:Tb thin films are described. Especially, the key-role of terbium on properties of TiO2 matrix is discussed.
The particular group of passives are magnetic and capacitive devices, which electrical parameters are tightly correlated with their geometry. A great variety of inductors and capacitors manufactured in different technologies are commonly applied in electronic circuits. Special attention should be paid at planar components that can be easily fabricated for example by thick-film and LTCC technology and integrated in Multi-Chip Modules (MCM). This paper presents some theoretical studies of planar inductors and capacitors. Specialised software for high-frequency EM (Electromagnetic) analysis was used for investigation of correlations between geometry of planar components and its basic parameters. Influence of planar dimensions, width of conductor paths and spacing on inductance/capacitance, quality factor and resonance frequency was determined.
A fiber optic delay line filter is presented using a cascaded structure of two Mach-Zehnder interferometers to obtain full adaptive dispersion slope compensation simultaneously for multichannel WDM systems at bitrates of 40 Gbps and above.
We investigated the conditions for obtaining negative refraction in photonic crystals fabricated in gallium nitride (GaN). Negative refraction at the interface between air and two-dimensional photonic crystals was numerically analyzed using Plane Wave Expansion Method (PWE) and Finite Difference Time Domain Method (FDTD). To describe the origin of negative refraction we have carried out simulations of equifrequency surfaces (EFS) of each photonic crystal structure. The presence of negative effective refractive index has been shown in two dimensional photonic crystal with hexagonal lattice of air holes etched in GaN. We have also observed all-angle negative refraction without existence of negative refractive index for 2D photonic crystal with square lattice of air holes. Additionally, the superlensing effect as a potential application of negative refraction in two dimensional photonic crystal was simulated.
The passives (resistors, capacitors, inductors) embedded in printed circuit boards (PCBs) can improve electrical properties and reliability of electronic systems. Pulse durability is an important parameter of passive components and active devices. In the case of resistors it allows to determine many properties including maximum power dissipation, resistance change or phenomena occurring in resistor structures after pulse surging. Furthermore pulse durability defines utility for pulse circuits. Thus this work presents pulse durability of thin-film resistors made on the surface or embedded in Printed Circuit Boards. Investigated test structures were made of nickel-phosphorus (Ni-P) alloy on FR-4 laminate with sheet resistance 25 Ω/sq or 100 Ω/sq. Pulse durability was determined by calculating the maximum nondestructive electric field, maximum nondestructive surface power density or maximum nondestructive volume power density. These parameters were determined in dependence on pulse duration, resistor geometry (length, width, aspect ratio), type of cladding, laser trimming and accelerated aging process.
The Quasi-Light-Storage (QLS) is a method for the variable and almost distortion free storage of optical data which is based on the filtering of the spectra with stimulated Brillouin scattering (SBS). The natural gain bandwidth of SBS limits the storage time of this method to 100 ns. We overcome this limitation by using a narrowed gain for the SBS and a fiber loop, respectively.
Fabrication of micromirrors inclined at 45° towards substrate is studied in this paper. The micromirrors are fabricated by anisotropic etching of monocrystalline silicon in KOH aqueous solutions saturated with different alcohols. The micromirror is formed by {110} sidewall inclined at 45° towards {100} substrate. The influence of propyl and butyl alcohols on etching anisotropy and surface morphology of micromirror structures is investigated. The impact of KOH concentration on micromirrors' parameters is also examined. The results show that the best etching anisotropy is achieved in the solutions with isopropanol and tert-butanol, and at the low concentration of KOH. Although the {110} mirror planes are patterned with stripes in the case of all considered etching solutions, the surface morphology of the {100} substrate is different for different alcohol additives. Contrary to propyl alcohols, the {100} surfaces etched in the solutions with butyl alcohols are densely covered with pyramidal structures (called hillocks). The angle of the micromirror inclination towards the substrate is evaluated by microscopic measurements and compared with the results reported in the literature.
Undoped and doped TiO2 nanoparticles were prepared from titanium tetraisopropoxide hydrolysis using sol-gel method. TiO2 nanoparticles were dried and then annealed at 120 °C for 2 h and used without any other treatments for characterization and photocatalytic measurements. Characterizations of nano titania powders were carried out with several experimental techniques such as Thermal Analysis (DSC/TG), X-Ray Diffraction (XRD), Scanning Electron Microscope and Energy Dispersive X-ray spectroscopy (SEM/EDX), UV-Vis spectrophotometry, and Raman spectroscopy. Methyl orange photocatalytic degradation by TiO2 powders was investigated.
For realizing a fiber optic attenuator bending losses and transition losses between the bent and plane fiber are used. In this paper the realized attenuators will be characterized by several measurements. Their attribute to attenuate a signal will be conclusively verified experimentally.
Extensive studies on reactively magnetron sputtered aluminum nitride (AlN) thin films and the evaluation of the material properties influenced by the deposition parameters were performed utilizing statistical methods. The use of the inverse piezoelectric effect of poly-crystalline AlN thin films in actively deformable micro mirrors are of prior interest for this work. To achieve piezoelectric material properties but also to respect technological conditions in MOEMS manufacturing processes the textural quality, the grain size, the intrinsic material stress, the deposition rate and therefore the non-uniformity in layer thickness are investigated. Wide, randomized series of experiments on process pressure, nitrogen / argon gas flow ratio, plasma rf power and target to substrate separation of the AlN sputter deposition process on amorphous titanium aluminid thin films on silicon substrates were performed. Polynomial based models of the thin films properties influenced by the deposition parameters are presented. The qualities of these models are evaluated by statistical methods. With the use of these models advantageous set points of the deposition process are presented. This set points enables highly textured polycrystalline AlN films, low or zero stressed films, big grain size and low non-uniformity in layer thicknesses.
In the paper the lithography methods are presented. Also a lithography with use AFM systems is summarized. In the work the reconstruction of the pattern created by nanoscratching and lift-off technique is show and discussed. The resolution of created structures for certain parameters of nanoscratching was also defined. Obtained resolution of reconstructed pattern was about 120 nm what was comparable with the thickness of gold masking layer.
Miniaturized impedance sensors with interdigitated gold electrodes were fabricated on silicon micromechanical cantilevers. They can be used for measurement of physicochemical properties of sensor's environment. Changes of impedance spectra of sensor were examinated in selected vapor and liquid environments with various components concentration. Impedance spectroscopy was used to measure electrical response of sensor and obtain usable information from it. Experimental characteristics were approximated with electrical equivalent circuit. Model parameters for few points of humidity and NaCl concentration in solution were calculated. Study of changes of model parameters allowed to evaluate concentration changes of environment components contacting with clean and functionalized sensors surface. Functionalization of electrodes surface by suitable chemical substance may provide possibility of building a very accurate and efficient selective sensor designed to monitoring presence and concentration of selected substance in sensor's environment.
Efficient tapers that match the compact modes of photonic crystal (PhC) waveguides to the larger modes of ridge waveguides or optical fibers are key building blocks for matching PhC based devices to standard optics. We have investigated the design, fabrication and measurement of PhC tapers and waveguides. The photonic crystal structures are all based on a triangular lattice of air holes in an AlGaAs/GaAs slab heterostructure. High resolution electron beam lithography together with a combination of dry and wet etching was used to fabricate the structures. The transmission measurements of the waveguides and tapers was carried out by the end fire method. A tunable semiconductor laser with a tuning range from 1240 nm to 1347 nm was used as a light source. The TE polarized light was launched into the waveguide from a polarization maintaining lensed fiber. The losses were determined by two methods that do not depend on a knowledge of the coupling efficiency between the fiber and the waveguide. The first (Hakki Paoli) is based on an analysis of the fringe contrast of the transmission spectrum. The other approach uses a Fourier analysis of the transmission spectrum.
In the paper the results of nanoscratching of gold metal layer deposited on resist made with application of a nanoindenter are presented. Also in the paper the properties of nanoscratching as nanotool are presented. The authors showed what problems exists in application of nanoindenters as systems used for nanoscratching lithography.
Over the last decade a tendency towards increasing demand for broadband wireless services is one of the driving factors for research and development. In order to connect the installed fiber optic backbone with remote wireless base stations at those frequencies full optical access networks are expected to play a key role for future system architectures. This Radio-over-Fiber-Systems combining optical and wireless access are one of the most dynamic topics in current research on broadband communications. The paper will introduce into the field of Radio over Fiber systems, analysing the underlying principles on system level. The main problems arising from the characteristic of the fiber-optic link are evaluated in terms of their effect on the system performance. Finally different system architectures will be presented in order to provide an introduction into Radio-over-Fiber-Systems as technology for next generation wireless access.
In this paper an ultra-low power VCSEL with an electrical consumption of below 5 mW is characterised to electrical power, optical power, temperature as well as a spectral investigation. First the pigtail manufacture is described, where amongst others the VCSEL is bonded on a ceramic carrier and connected to an optical fibre by front surface coupling. Thereby the fibre-chip coupling is realised by using index matching adhesive as well as active alignment. Finally the results of the characterisation are analysed to find optimal operation conditions. For comparison results of a common VCSEL are shown.
We present a method for ultrahigh-resolution optical spectroscopy based on stimulated Brillouin scattering (SBS). The resolution of conventional spectrometers is limited by the natural bandwidth of the SBS. We enhance the resolution by a reduction of the natural SBS gain bandwidth. By a superposition of the natural gain with two losses, we were able to increase the spectrometer resolution from 20 to 8 MHz. We will confirm this in a first proof of concept experiment.
In this paper electrical and antistatic properties of magnetron sputtered thin films based on TiO2:(V, Ta) were investigated. Ability to dissipate static charge from the surface is important issue in case of various types of materials. Static electricity can cause a lot of risks and problems, especially in hazardous places and environments. Antistatic properties of different thin films were assessed on the basis of resistance values and decay times of static charge. Decay times of static charge generated by corona discharge showed that investigation of resistance values of samples is insufficient in case of antistatic properties assessment. Samples of TiO2:(V, Ta), TiO2:(V, Ta, Co) and TiO2:(V, Ta, Cr) exhibited excellent ability to dissipate static charge from their surfaces, however thin film of TiO2:(V, Ta, W) has very poor antistatic properties due to very long decay time. This results are surprising, because TiO2:(V, Ta, Cr) exhibited the highest value of resistance, while decay time was the shortest from all measured samples.
