Proceedings Volume 6635

Advanced Topics in Optoelectronics, Microelectronics, and Nanotechnologies III

Ovidiu Iancu, Adrian Manea, Paul Schiopu
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Proceedings Volume 6635

Advanced Topics in Optoelectronics, Microelectronics, and Nanotechnologies III

Ovidiu Iancu, Adrian Manea, Paul Schiopu
View the digital version of this volume at SPIE Digital Libarary.

Volume Details

Date Published: 11 June 2007
Contents: 7 Sessions, 52 Papers, 0 Presentations
Conference: Advanced Topics in Optoelectronics, Microelectronics, and Nanotechnologies III 2006
Volume Number: 6635

Table of Contents

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Table of Contents

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  • Front Matter: Volume 6635
  • Plenary Session
  • Nanoscience and Nanoengineering
  • Physical Optics and Signal Processing
  • Laser and Biomedicine
  • Environmental and Chemical Sensors
  • Optical Communication, Modeling, and Simulation
Front Matter: Volume 6635
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Front Matter: Volume 6635
This PDF file contains the front matter associated with SPIE Proceedings Volume 6635, including the Title Page, Copyright information, Table of Contents, Introduction, and the Conference Committees listing.
Plenary Session
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Experimental diagnostics of white-light vortices
The principles and the practical conditions for registration of phase singularities, such as optical vortices in the spectral components of white light, are discussed. Interference diagnostics of white light vortices in a polychromatic specklefield is reported for the first time.
Nanometrology of microsystems: traceability problem in nanometrology
Iuliana Iordache, D. Apostol, O. Iancu, et al.
Proper calibration of any instrument is vital to an investigator's ability to compare laboratory experiments, as well as to draw quantitative relations between experimental results and the real objects. Traceability is a term used to certify an instrument's accuracy relative to a known standard. Because traceability to meter is a very expensive and complicated process, accurate and traceable calibration of lateral and vertical standards (e.g. 1D and 2D gratings) is a basic metrological task for nano- and micro- technology. On the other hand laser interferometry is the de facto method to transfer the meter standard to practical measurement. In this lecture, we describe interferometric vertical and lateral calibration of a grating used to quantify the parameters necessary for proper translation of AFM data into physically meaningful data.
Theoretical and numerical analysis of the microring resonator refractometers
Theoretical and numerical studies regarding the possibility of using simple laterally coupled microring resonators as refractometers are presented in this work. We have considered a core waveguide layer with its refractive index varying in the range 1.5...2 deposed on the silicon dioxide thermal grown layer. The waveguide width is set for achieving single-mode condition at 1.55 &mgr;m radiation wavelength. The aim of this work is finding the optimum configurations for microring resonators based refractive index sensors.
Nanoscience and Nanoengineering
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Absorption and photoluminescence of Ga-La-S:O and Ga-Ge-As-S glasses doped with rare-earth ions
M. S. Iovu, A. M. Andries, N. N. Syrbu, et al.
The visible luminescence from Pr3+, Dy3+, Nd3+, Sm3+ and co-doped with Ho3+ and Dy3+ ions embedded in Ga0.017Ge0.25As0.083S0.65 glass hosts at room temperature and at T10 K is reported, when pumping with an Ar+-ion laser at lambda=488 nm. Fluorescence emissions at 1 .3 &mgr; was observed for Dy3+ and both at 1.3 and at 1.5 &mgr; for Pr3+ doped glasses with wavelength pumping at 950 nm. The emission bands correlate with the absorption bands characteristic for the electronic transitions of the rare-earth ions. Energy transfer from Ho3+: 5F3 level to Dy3+:4F9/2 level increase the visible emission efficiency at 650 nm in the co-doped glasses. The emission spectra correlate with the absorption spectra of the investigated glasses. The investigated Ga0.017Ge0.25As0.083S0.65 glasses doped with Pr3+ are promising materials for optical fibers amplifiers operating at 1300 and 1500 nm telecommunication windows. The effect of oxygen on the absorption and luminescence spectra of Pr3+-doped Ga-La-S-O (GLS) glasses with a constant cationic ratio Ga/La=O.7/O.3 and varying both oxygen (0.65 and 2.95 wt %) and praseodymium (0. 1 and 1 .0 wt %) content also are presented.
Optical encoder measurement technology
Iuliana Iordache, Mihaela Bojan, D. Apostol, et al.
A new approach to metrology for the range below 100 nm is based on large fiducial grids optical encoders produced by interference / lithography. Since the encoder can only be as accurate as the grating scale, advance in this area depends on the availability of encoder plates of nanometer accuracy. Various commercially available or home made holographic gratings were checked using interferometric methods and compared with the AFM device results. The budget of errors was analyzed and the necessary improvements of measuring technology are presented.
Enhancements of the Abelés method for refractive index determination
Petre C. Logofatu, Iuliana M. Iordache, Mihaela M. Bojan
The Abelès method is a classical method for determining the refractive index of dielectric thin films, based on the phenomenon oftotal transmission of p-polarized light at the Brewster angle ofincidence. In this paper we examined the main features of the method, such as the criterion for ruling out spurious solutions, in a formal manner, using closed form equations. We also investigated the method for ambiguities and we found out using rigorous analysis that the method is ambiguous, because there are unreported situations in which the spurious solutions cannot be distinguished from the real solution. The limits within which the method can be used, even in situations when ambiguities exist, are determined.
GHz sense amplifier for MRAM
Ionut Schiopu, Ovidiu Iancu
The performance of a novel current-steering logic sense amplifier is verified through simulations in 0.35 &mgr;m CMOS technology. Because the reading time affects destructively the MRAM cell by thermal dissipation and it also affects the consumption of power, a new sense amplifier is proposed, one that operates at high frequency, that has a reading time of the order of ns and a low power consumption. This sense amplifier uses the differential charge of the bit line capacity where the MTJ resistance determines the gain of the amplifying. The differential amplifying starts when the bit line voltage reaches a certain threshold. In this way we increase the sensitivity of the device and the two values of the MTJ resistance will be distinguished in a much shorter time. The output voltage will be stored in a latch structure as the maximum I minimum voltage level (VDD or gnd).
Light induced phenomena in amorphous As100-xSex and As40Se60:Sn thin films
Maria A. Iovu, Mihail S. Iovu, Diana V. Harea, et al.
Photostructural transformations in amorphous films of chalcogenide glasses (ChG) under light irradiation present scientific and practical interests. From scientific point of view, because the composition ofChG determine the kind of structural units and the mean coordination number, in the present work the amorphous films of the chalcogenide systems As1ooSe (x40÷98) and As40Se60:Sny (As50Se50:Sny) (y=O÷1O.O at.% Sn) were studied. The changes of the refractive index under light irradiation and heat treatment are calculated from the transmission spectra. The more sensitive to light irradiation are the amorphous films of As60Se40 and As50Se50, which exhibit big modifications of the refractive index ((delta-n/n) = 0.394).
Hardware simulator for design and characterization of MOEMS for environmental applications
Florin Caldararu, Alexandru Vasile, Mira Caldararu
The MOEMS for enviromnental applications have a complex structure architecture: a sensitive layer for environment interface, optical devices for radiation beam processing (waveguides on semiconductor) and photodiodes. The sensor includes an electronic module, used as transimpedance amplifier and phase shift detector and a radiation source coupled to the waveguide. Each of these sensor modules have specific parameters which must be optimized in order to obtain the best sensitivity for MOEMS, as well as to determine the appropriate concentration domain. The optimization process involves a great number of parameters and boundary conditions, so that a mathematical model is not sufficient. In this paper a hardware simulator for MOEMS design and characterization is presented. The structure and dynamics of environmental signal, the beani radiation processing and the power transfer from the environmental signal to the photogenerated current are physically simulated. An application of this simulator for design and characterization of aimnonia measurement MOEMS is presented.
Fault tolerant techniques for integrated circuits in submicron and nanotechnologies
Angelica Bacivarov
Drastic device shrinking, power supply reduction, and increasing operating speeds that accompany the technological evolution to deeper submicron, reduce significantly the noise margins and thus the reliability of deep submicron ICs. A more significant problem is related to the single-event upsets (SEUs). It is predicted that neutrons produced by the sun activity will affect dramatically the operation of future Integrated Circuits (Ics). Self-test and fault tolerance in submicron and nanotechnologies becoming hitherto imperative. Perhaps the most significant problem concerns the sensitivity of future IC generations face to various noise sources, and in particularly face to energetic particles. This paper analyses some of designing soft-error tolerant circuits.
Polarization properties of volumetrical and surface scattering of optically heterogeneous media
A. D. Arkhelyuk, L. I. Podkamen
The investigation results of surface and volumetric scattering of polarized radiation by oriented particles on the basis of Muller matrixes are presented. The regularities of angular dependencies of non-zero fik components of mirror reflection matrixes on scattering angles and particles orientation are more sensitive to structure parameters of surface relative to fik diffuse reflection matrixes at small radiation angles. The maximal optical thickness of atmosphere layer under which it is possible to estimate the presence and degree of orientation of crystal formations by its transmission matrix is determined.
Physical Optics and Signal Processing
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The reduction of the physical inputs number to optoelectronic logical gates
Vasile Degeratu, Paul Schiopu, Stefania Degeratu
In this paper the authors present elementary logical gates achieved into optoelectronic technology. The main characteristic of these logical gates is that the physical number of inputs ofthese gates is half versus the number of input signals. The light intensity of input signals is amplified, the information being given by direction of light polarization. The polarization is important into optical computing because with its help the operations with negligible energetically losses can be achieved. The presented logical gates would be use into optoelectronic and optic circuits by processing of information. They can be use into optoelectronic and optic circuits for that the addressing is made parallel, too.
Study of speckle-field dynamics scattered by surface of concrete during congelation
Thorough description of diaphragm size selection for detecting the intensity of laser beam scattered on surface of congelating cement was given. Also fluctuations of speckle-field and its connection with square derivative of intensity were investigated. Analysis was based on CCD images of speckle-field dynamics in process of cement hydratation.
Optical bistability of layer semiconductors in the exciton absorption region
Claudia Yu. Zenkova, Valerij M. Kramar, Natallya K. Kramar
The theoretical investigation of the role of bending waves in the process of creating conditions for observing optical bistability in layer semiconductors was performed by the Green function method. Using the 2H-polytype of Pb12 as an example. we showed that effective exciton scattering by oscillations of this type leads to a short wave shift of the frequency tegion. the decrease of its sizes. the widening of the temperature interval optical bistability realization of its observing, the shill the hysteresis loop into bigger intensities and the decrease of its height and width.
A global study about optical 4f image processing filters
Our goal in this paper is to make a comparative study about 4 f filters. The filters are in the same configuration and we study three different situations: - ideal case - aperture with one aberration - each lens with one aberration Aberrations are characterized by orthogonal Zernike polynomials; aperture and lenses have their proper transfer functions. We have an input signal and the purpose of this paper is to see how the properties of the input signal changes at the output in the three situations analyzed and to make a comparison between them.
Simple LSI image acquisition system analysis
Our goal in this paper is to make a study about a simple optical images acquisition system. We focus our analyses to optoelectronic aspects using Fourier optics to compute PSF (point spread function) and MTF (modulation transfer function). We use an optical sensor and a CCD (charge coupled device) image sensor to make an image acquisition sensor. Optical sensor is made by a lens and image sensor has an appropriate pixel aperture dimension to reduce Nyquist frequency needed to eliminate alias in CCD image sensor. We compute the PSF and MTF for lens which has two aberration power and coma and for CCD image sensor optical part. We present an image at each checking point and we see how the original image is transformed as it propagates to optical and image sensors.
Control charts for non-Gaussian distributions
Florina Babus, Abdessamad Kobi, Th. Tiplica, et al.
Traditional statistical process control (SPC) techniques applied in the industrial processes field consider often that the distribution ofdata is Gaussian. The estimation ofparameters, the detection ofthe out oforder situations and the control of the followed characteristics are easy to achieve for the normal populations. In reality, whatever the origin of a characteristic (large series productions for components, mechanical parts of OE communication systems, etc. ) the curve of distributions of the measured values is generally far from being normal. The simple approximation to the Gauss distribution and the use of the classical control methods sometimes induces serious errors. In this paper, a study on the statistical control of non Gaussian populations is presented. Particularly we discuss the Rayleigh and the Weibull distribution as being representatives in (SPC for some category of data. The X control charts with variable limits are tested. Experimental simulations are presented for different parameters of the two distributions. The results confirm the methodology and encourage the research in the field of non Gaussian processes.
Young's diagnostics of phase singularities into polychromatic light fields
Olexiy O. Arkhelyuk, Christina V. Felde, Halina V. Bogatyryova, et al.
Two original approaches for the diagnostics of phase singularities (such as optical vortices, screw dislocations of a wave front) based on the Young-Rubinowicz mOdel of diffraction phenomena are represented. Both techniques are implemented without using a separate reference wave, as in common interference techniques. That is why they are very convenient for analysis of spatially coherent polychromatic fields. The first technique is based on the use of an opaque strip as the diffraction device. Bending Young's interference fringes produced by the edge diffraction waves from two rims of the strip within the geometrical shadow region reflect helicity of a wave front, so that the direction and magnitude of bending correspond directly to the sign and the modulus of topological charge of the optical vortex, respectively. This technique is practicable for diagnostics of isolated polychromatic vortices, such as "rainbow" Laguerre-Gaussian mode, where the condition of mutual spectral purity is satisfied. Another technique is based on the use of knife-edge diffraction. The edge of an opaque screen serves as the source of a reference wave, which interferes with the tested field within the directly illuminated region. One observes typical interference forklets near the geometrical shadow boundary, which detect optical vortices. This technique is more applicable to diagnostics of phase singularities in polychromatic speckle fields due to the condition of mutual spectral purity is satisfied automatically.
Laser and Biomedicine
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Polarization speckle-reconstruction of biological tissues architectonics: Part 1. Polarization correlometry of birefringence architectonics: singular approach
A. O. Angelskaya, Yu. A. Ushenko, Ye. Ushenko, et al.
The interconnection between topological and statistic (correlation) approaches in the description of mechanisms of forming polarization inhomogeneity of the biological object's images have been discovered.
Polarization phase reconstruction of biological tissue architectonics: Part 2. Study of polarizing intercorrelative function of coherent images of phase-inhomogeneous layer anisotropy
A. O. Angelskaya, A. G. Ushenko, Yu. A. Ushenko, et al.
The correlation structure of 2-D Stokes vector parameters of physiologically normal and pathologicaly changed biotissues is investigated. The totality of diagnostically urgent interconnections between biotissue physiological state and statistical moments of 2-D Stokes vector parameters is found.
Polarization phase reconstruction of biological tissue architectonics: Part 3. Polarizing-correlative processing of images of statistical objects in the problem of visualization and topology reconstruction of their phase heterogeneity
A. O. Angelskaya, A. G. Ushenko, Yu. A. Ushenko, et al.
The interconnection between geometry of biotissue structure with their polarization properties has been studied. It has been shown that for physiologically normal biotissues polarization properties of radiation scattered on architectonic nets formed by protein fibrils possess the fractal character. Pathological changes of biotissues architectonics are accompanied with the transformation of self-similar structure of Mueller-matrix images into stochastic and statistic ones.
Polarization phase reconstruction of biological tissue architectonics: Part 4. Coherent introscopy of phase-inhomogeneous surface and layers
A. O. Angelskaya, A. G. Ushenko, Yu. A. Ushenko, et al.
Specific features of the formation of local and statistical polarization structures of laser radiation scattered in phaseinhomogeneous layers (PIL) of biological tissue (BT) were studied. The distribution of azimuth and eccentricity of boundary field polarization was found to correlate with the orientation-phase structure of multifractal PIL. A method of polarization phase reconstruction of BT architectonics was suggested.
Polarization singularities of biological objects speckle-fields
Oleg Angelsky, Alexander Ushenko, Sergej Yermolenko, et al.
The interrelations between statistics of the lst-4th orders of the ensemble of Mueller-matrix images and geometric structure of birefringent architectonic nets of different morphological structure have been analyzed. The sensitivity of asymmetry and excess of statistic distributions of matrix elements Cik to changing of orientation structure of optically anisotropic protein fibrils of physiologically normal and pathologically changed biological tissues architectonics has been shown.
The techniques and results of biocorrectors energy-informational influence registration
M. S. Gavrylyak, P. P. Maksimyak, L. J. Podkamen
This paper presents the possibility of using dynamical characteristics of distillated water structurization process as a sensor of the influence. It is conditioned with biological water importance, on the one hand, and its valuable structural and informational properties, on the other hand.
Refractive index measurement using comparative interferometry
Mihaela Bojan, D. Apostol, V. Damian, et al.
The refractive index of a material medium is an important optical parameter since it exhibits the optical properties of the material. The adulteration problem is increasing day by day and hence simple, automatic and accurate measurement of the refractive index of materials is of great importance these days. For solid thin films materials Abeles method was reconsidered. Quick, measurements of refractive index using simple techniques and refractometers can help controlling adulteration of liquids of common use to a greater extent. Very simple interferometric set-up using Fizeau fringe patterns compares the fringe pitch as obtained in a cell with two levels: one down level with the unknown refractive index liquids and the upper level with gas air. A CCD matrix and a PC can handle the data and produce the results up to for digits.
Study of light-scattering by ferro-nematic suspension
At present time a liquid crystals using in engineering are based on their optical properties such as strong anisotropy, specific equilibrium of molecular skeleton, sensitivity to external action, appearance of compound and involute structure which selectively respond to the light with adjusted frequency and polarization, etc. This behaviour make them are perspective environment for application in optical devices like mesomorphic active components (electrooptic shutters, spherical and cylindrical lenses, optical filters, light-induced time and space grids, nonlinear mirrors).
Analysis of conversion efficiency of internal second-harmonic generation in InGaAs quantum-well laser diodes emitting around 960 nm
F. Puntaru, N. N. Puscas
Based on the obtained experimental results in this paper we report some theoretical results concerning the realization of the phase-matching conditions for the internal second-harmonic generation in InGaAs quantum-well laser diodes emitting around 960 nm in order to enhance the conversion efficiency. The theoretical results obtained by numerical integration of the coupled amplitude equations corresponding to the fundamental and second liannonic concerning the interaction length and generation efficiency are in good agreement with the experimental data. The role of the phase-mismatching in the spectral distribution of the internal second-harmonic generation in the CW operation of the above mentiond lasers is also analysed. The emission of pairs of narrow blue-green peaks having perfectly symmetrical spectral positions with respect to the central peak of pure second-harmonic generation at 480 urn is most probably enhanced by a mechanism of reciprocal cancellation of the respective phase-mismatch vectors. The obtained results are important for the assessment of the relationship between the structural parameters of the laser and the conditions which contribute to the stimulation of second-order optical nonlinearities in the laser active region.
Environmental and Chemical Sensors
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Interference diagnostics large-scale surfaces
The feasibilities for optical correlation diagnostics of a rough surface with large surface inhjmogeneities by determining the transformations of the longitudinal coherence function of the field scattered by such surface are substantiated and implemented.
Surface-barrier sensors on basis of zinc selenide
V. P. Makhniy, L. I. Arkhilyuk, V. V. Mel'nyk
The paper presents results of experimental investigations of electric and photoelectric properties of the surface-barrier diodes Ni-ZnSe.
Time-averaged vibration mode viewing with DSPI
F. Garoi, D. Apostol, A. Sima, et al.
We discuss an experiment for detecting small deformations by speckle interferometry. Vibration modes of an aluminium plate are observed by digital speckle pattern interferometry (DSPI). A Mach-Zender interferometer arrangement is used and the speckle interferograms are recorded with a CCD camera and processed on a computer. These fringes depend on the path differences due to the vibration of the aluminium plate from its original state. Vibration amplitudes between 0.3-0.6 &mgr; were measured for seven vibration modes.
CMOS integrated structures with optical sensors
Emil Sofron, Paul Vulpoiu, Paul Burciu
Based upon analog and digital circuits, the structure of the introduced circuit (Imager) is roundly incorporating an array of approximately 1.3 million pixels, placed on rows and columns. The signals, generated by pixels which are represented as CMOS sensors, are transmitted to a processing analog circuit consisting of a primary amplifying block, a secondary amplifying block, a programmable gain amplifier and an AD converter.
Autonomous remote sensing with SAW devices
Ovidiu Iancu, Paul Schiopu, Adrian Manea, et al.
In so rapidly growing sensing technology, Autonomous Surface Acoustic Waves (SAW) based sensors, offer high flexibility for modern identification/sensing systems, and represent a new perspective for remote monitoring and control. This paper gives a presentation of operating principles of wireless SAW sensors with separation in frequency (frequency domain division-FDD) and separation in time (time domain division-TDD). The design of interdigitated transducers (IDT), and reflectors on the different types of substrate materials as piezo crystals LiNbO3, LiTaO3 or quartz in connection with application domains is presented. A comparison between Time Domain Sampling-TDS and Frequency Domain Sampling-FDS principles of transmitter and receiver, gives evidence of their advantages and disadvantages. A part of the paper dealt with the measurement results.
The detection limit of magnetic microsensors
Cornel Panait, George Caruntu
An essential parameter in the setting up of the performance of the measurement systems that uses Hall microsensors is the detection limit of such devices. This paperwork presents the structure, the operating conditions, and the main characteristic for the Hall semiconductor plates and for double-collector magnetotransistors. By using numerical simulation, the values of signal-to-noise ratio and the detection limit for the two analyzed devices are compared and it is also emphasized the way in which choosing the geometry and the material features allows getting high-performance sensors.
The optimization of magnetic sensitive MOSFET structures
George Caruntu, Cornel Panait
The optimal processing of sensors-provided signal, imposes their integration on the same chip, with the amplifier circuit. In this paperwork, based on the model of dual Hall devices, it is analysed the operating conditions, and are established the noise main characteristics for double drain magnetotrasistor structure realised in the MOS circuits technology. Using numerical simulation it is emphasized the way in which the geometry and material properties influence on the device performances. There are also presented and described the electrical diagrams of the transducers which contain such sensors.
Preparation and characterization of indium tin oxide films by sol-gel method
Alina Ciuciumis, Ileana Cernica
Sol-gel technology is a relatively simple and cheap process to deposit oxides under thin film form out of a sol. The experiments were developed in order to obtain nanomaterials by sol-gel method; nanomaterials that mixed with resin and additives can be deposited in thin and uniform films by spraying on different lignocellulosic composite surfaces. This method assures a functional finishing of the nanomaterials. These films are transparent and the surfaces are flat with no cracks. The influence of substrate type, morphology of the films and of the substrates before and after deposition was studied by means of optical microscopy, scanning electron microscopy (SEM) and atomic force microscopy (AFM). The sol-gel deposit on the lignocellulosic composite substrates lowered the sorption rates of water and water vapours.
Synthesis of yttrium aluminium garnet doped with cerium for application in a new generation luminescent lighting devices
Vasilica Schiopu, Mugur Macrin, Ileana Cernica
Future electric lights will be composed of white LEDs (Light Emitting Diodes) and for this reason the development of new luminescence materials has become a great challenge to researchers. In the present paper it is presented a sol-gel method, simple and with superior potential for synthesis of nanoparticles of yttrimn aluminium garnet doped with cerium luminescent powders. This method has a big potential for application in new generation luminescent lighting devices. The gels were prepared using stoichiometric amounts of reagent-grade Y203 and A1203 as the starting materials. The XRD pattern of the powder calcinated al 1100°C shows the formation of single-phase nano-crystal garnet materials. The XRD measurements and AFM measurements show that we obtained a phosphorus with grain size of 24 nm. The emission spectra of white LED demonstrate that acquired phosphor has good applicability in optoelectronics.
Optical Communication, Modeling, and Simulation
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A survey of two-dimensional codes for optical CDMA
Petre Stroica, Marian Vladescu, Ovidiu Iancu
The paper presents the implementation of an optical CDMA system with two-dimensional coding using wavelength channels and time chips to create the codeword. Computer simulations have been performed in order to analyze and optimize the electronic circuits. The experimental work has been designed in order to investigate and evaluate the capabilities ofthe implemented optical CDMA system.
Advanced methods for electromagnetic investigation of PCB/PWB layouts
N. D. Codreanu, C. Ionescu, P. Svasta, et al.
High Density Interconnect (HDI) technology is a way to condense electronic circuits for ruggedness, radiation hardening, and high performance. HDI minimizes the size and weight of electronic products while maximizing their performances. HDI circuits offer new solutions to signal integrity (SI) and electromagnetic compatibility (EMC) concerns, concerns which are expected to grow more and more as rise/fall times continue to drop. Because PCB manufacturers have developed new materials and technological solutions, indispensable at this moment is to perform a deep virtual characterization of structures directly related to HDI. This paper presents investigations and results focused on the main areas of SI and EMC, as noise at PCB level (reflections, and crosstalk), electromagnetic interference (EMI) and on-board interconnection delay. The authors have evaluated various HDI-PCB items and structures using the MoM full-wave electromagnetic simulation method. After modeling and simulation a link to classical circuit simulators was created by extracting RLCG elements and various parameters, which are directly related to the total current along the HDI structures. The paper offers a new way to find the solutions for keeping the integrity of signals and electromagnetic compliance.
Design of Optoelectronics Research Center website
Popescu Razvan Nicolae, Paul Schiopu
An organization's presence or an individual's presence on the World Wide Web. A Web site is a collection of Web pages, which are documents coded in HTML that are linked to each other and very often to pages on other Web sites. A Web site is hosted on a server by its owner or at an ISP. It may share space on the server with other Web sites,reside on a server dedicated to that Web site only or be on multiple dedicated servers. To qualify as a Web site, the Web server must be available on the Internet 24 hours a day.
GSM-Railway as part of European Rail Traffic Management System
GSM-R is a vital component inside the ERTMS which is also an essential element of European Community rail projects; investment in equipping and the rolling stock with ERTMS could reach 5 billion eurodollars in the period 2007-2016. GSM-R is the result of over ten years of collaboration between the various European railway companies, the railway communication industry and the different standardization bodies. GSM-R provides a secure platform for voice and data communication between the operational staff of the railway companies including drivers, dispatchers, shunting team members, train engineers, and station controllers. It delivers advanced features such as group calls, voice broadcast, location based connections, and call pre-emption in case of an emergency, which significantly improves communication, collaboration, and security management across operational staff members. Taking into account the above mentioned, the paper will permit to audience to discover the GSM-R network architecture, services and applications proposed by this technology together with the future development and market situation due to the market liberalization.
Study of dynamic coherent light-scattering in the process of phase transition in liquid crystals
M. S. Gavrylyak, P. P. Maksimyak
The results of experimental study of fluctuations of a coherent field intensity scattered by nematic liquid crystal during phase transition liquid-liquid crystal are presented. It has been shown that chaos in the scattered field increases with the growth of plate thickness of liquid crystal.
Defect and fault modelling of a CMOS n-diffusion photodiode
Andrei Dragulinescu, Livier Lizarraga, Salvador Mir, et al.
Today, the CMOS image sensors are being used in an increasing number of applications. A significant problem for these devices is due to the fact that the production testing is complicated and expensive. This problem arises from the need to use light sources in order to test the photosensitive elements. As an alternative solution, we proposed the use of a test performed in the absence of light. In order to evaluate the quality of the proposed test approach, we performed an analysis of the defects and failure mechanisms in the photodiode. This is the main contribution of the paper, as until now very little literature was written concerning this subject, due to the fact that these defects are not well enough understood to enable the development of a general model.
Wavelength division multiplexing WDM, CWDM and DWDM applications
Irina Bristena Vasile, Alexandru Vasile, Stan Luciana, et al.
The fiber optics has become the most preferred media for this very large data traffic. TDM (Time Division Multiplexing) has been the most practical method to divide the significant capacity of a single fiber optics into several communication channels. This technology is still limited by the large complexity of high-flow modulation and multiplexing equipment. Presently, a complementary approach proves its potential: Wavelength-Division Multiplexing (WDM). The evolution of WDM allows now a very small spacing between channels wavelength, in nm, generating DWDM (Dense Wavelength Division Multiplexing). The networks with individual fibers including more than 100 independent optic channels, as well as those with bidirectional flow are already available on the market. CWDM (Coarse Wavelength Division Multiplexing) represents an economical application of a mature technology which may provide options where the capacity of fibers is limited.
Simulation design in Java for digital image processing
M. Kadar, I. Ileana
This paper discusses the main steps in creating simulations for digital image processing. The basic theory that describes the behavior is presented with the basic parameters, the environment of the experiment, the level of detail. approximations of the physics discussed.
Modeling of electromagnetic fields reflected by runes
O. P. Maksimyak, L. Y. Podkamen
The technique of computer design of the parameters of the electromagnetic field reflected by the FEHU rune is shown. The geometrical optics techniques are used for the exact analysis of the phase vibrations reflected by the rune. We demonstrate influencing of the Fehu rune on same bio-object parameters, which were used as the detector of action.
Admin interface of Optoelectronics Research Center
Popescu Razvan Nicolae, Paul Schiopu
The scope of the Optoelectronics Research Center website is to provide useful information about the center such as: member's cv, projects, conferences, as well as many other related information's. Based upon a worldwide study a visitor pay attention to a website for about 50-60 seconds, in this time he(she) is searching the website pages for the desired information, if the information it's found in this period the visitor will be pleased, if not he will look the information on other websites. For the CCO website a user-friendly environment has been designed, this interface has been severely tested, the results matching the 50-60 seconds time. In more than 80% of the cases the webmasters are not the same with the webdesigners; this is the point where the problems frequently occur. The content of a website has to be updated in order for visitors to get the proper information's, and not to be misled. To overcome this problem an administrator interface has been constructed. Using the admin interface the webmaster will easily update the whole website with only few clicks of a button, without need to know anything about programming or webdesign.
Life testing of electronic components: a Bayesian approach
Sorin Voiculescu, Fabrice Guérin, Ioan C. Bacivarov
A common problem of high reliability computing is, on one hand, the magnitude of total testing time required, particularly in the case of high reliability components and, on the other hand, the number of devices under test. In both cases, the objective is to minimize the costs involved in testing without reducing the quality of the data obtained. One solution is based on accelerated life testing techniques which permit to decrease testing time. Another solution is to incorporate prior beliefs, engineering experience, or previous data into the testing framework. It is in this spirit that the use of a Bayesian approach can, in many cases, significantly reduce the amount of devices required. The accelerated life testing (ALT) of electronic components (including the semiconductor devices) under severer than operating conditions involving high temperature, humidity, voltage, a.o. is commonly used to reduce test time and cost. The main problem is to estimate accelerated life model parameters allowing to define the reliability function under operating conditions from only accelerated life data. A difficulty of using the ALT, during design stage, is due to the small sample size to test. In this context, the Bayesian approach can be used to incorporate into the estimation process all available knowledge on accelerated life model (baseline failure rate, activation energy, a.o). This paper presents the study of Exponential-Arrhenius model by an evaluation of parameters using maximum likelihood and Bayesian methods. A Monte Carlo simulation has been performed to examine the asymptotic behavior of these different estimators.
Evaluation of the attenuation and the optical coupling between optical fibers and waveguides
S. Ghinoiu, L. A. Puscas, E. M. Rotaru, et al.
In this paper we report some experimental and theoretical results concerning the characterization of the coupling between optical fibers and optical waveguides using nondestructive methods. The optical transmission method was used for the measurement of the optical attenuation in graded index profile optical fiber (&lgr;=0.63 &mgr;) and the resonator method for Ti:LiNbO3 optical waveguides (&lgr;=1.55 &mgr;). The refractive-index profiles of optical fibers characterized by a graded index profile and Ti:LiNbO3 optical waveguides has been determined for &lgr;=1.55 &mgr; from near field intensity measurement using a standard optical fiber as receiver. The obtained results are in good agreement with other obtained by several authors and can be used for the design of optical fiber sensors and optoelectronic integrated circuits.
General artificial neuron
Vasile Degeratu, Paul Schiopu, Stefania Degeratu
In this paper the authors present a model of artificial neuron named the general artificial neuron. Depending on application this neuron can change self number of inputs, the type of inputs (from excitatory in inhibitory or vice versa), the synaptic weights, the threshold, the type of intensifying functions. It is achieved into optoelectronic technology. Also, into optoelectronic technology a model of general McCulloch-Pitts neuron is showed. The advantages of these neurons are very high because we have to solve different applications with the same neural network, achieved from these neurons, named general neural network.
The spatial coding of intensity into neural network
Vasile Degeratu, Paul Schiopu, Stefania Degeratu
In this paper the authors describe the coding mode of stimuli intensity into neural network and present two neural networks into opto-electronic technology that codify spatial the input signal intensity. The study utility of mode by coding of intensity into neural network derives from numerous by applications that can have the utilization of coding mode of information. Thus the neural networks presented in this paper have many applications. They can be used into artificial systems that process external or internal stimuli by different intensities achieving decoding of these stimuli, they can be used in the color television, they can be used for neural computers into process by coding of information, etc.
Estimation of the influence of the shape and size of nonspherical particles in polarized light
A. D. Arkhelyuk, L. I. Podkamen, Ion Gruia
The experimental investigation results of the influence of the shape, size and orientation degree of nonspherical particles of the model pattern on the change regularities of normalized components of scattering and extinction matrixes are presented. The component of light field and experimental situations which are most advisable for the estimation of particles optical-geometrical parameters is obtained.