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A new photonic integration technique is presented, based on the use of an indium phosphide membrane on top of a silicon chip. This can provide electronic chips (CMOS) with an added optical layer (IMOS) for resolving the communication bottleneck. A major advantage of InP is the possibility to integrate passive and active components (SOAs, lasers) in a single membrane. In this paper we describe progress achieved in both the passive and active components. For the passive part of the circuit we succeeded to bring the propagation loss of our circuits close to the values obtained with silicon; we achieved propagation loss as low as 3.3 dB/cm through optimization of the lithography and the introduction of C60 (fullerene) in an electro resist. Further we report the smallest polarisation converter reported for membrane waveguides ( 95% polarisation conversion efficiency over the whole C-band and tolerant fabrication. We also demonstrate an InP-membrane wavelength demultiplexer with a loss of 2.8 dB, a crosstalk level of better than 18 dB and a uniformity over the 8 channels of better than 1.2 dB. For the integration of active components we are testing a twin guide integration scheme. We present our design based on optical and electrical simulations and the fabrication techniques. © (2014) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only., A new photonic integration technique is presented, based on the use of an indium phosphide membrane on top of a silicon chip. This can provide electronic chips (CMOS) with an added optical layer (IMOS) for resolving the communication bottleneck. A major advantage of InP is the possibility to integrate passive and active components (SOAs, lasers) in a single membrane. In this paper we describe progress achieved in both the passive and active components. For the passive part of the circuit we succeeded to bring the propagation loss of our circuits close to the values obtained with silicon; we achieved propagation loss as low as 3.3 dB/cm through optimization of the lithography and the introduction of C60 (fullerene) in an electro resist. Further we report the smallest polarisation converter reported for membrane waveguides ( 95% polarisation conversion efficiency over the whole C-band and tolerant fabrication. We also demonstrate an InP-membrane wavelength demultiplexer with a loss of 2.8 dB, a crosstalk level of better than 18 dB and a uniformity over the 8 channels of better than 1.2 dB. For the integration of active components we are testing a twin guide integration scheme. We present our design based on optical and electrical simulations and the fabrication techniques

240,000 participants have a screening for diagnosis of pneumoconiosis every year in Japan. Radiograph is used for staging of severity in pneumoconiosis worldwide. This paper presents a method for quantitative assessment of severity in pneumoconiosis using both size and frequency of lung nodules that detected by thin-section CT images. This method consists of three steps. First, thoracic organs (body, ribs, spine, trachea, bronchi, lungs, heart, and pulmonary blood vessels) are segmented. Second, lung nodules that have radius over 1.5mm are detected. These steps used functions of our developed computer aided detection system of chest CT images. Third, severity in pneumoconiosis is quantified using size and frequency of lung nodules. This method was applied to nine pneumoconiosis patients. The initial results showed that proposed method can assess severity in pneumoconiosis quantitatively. This paper demonstrates effectiveness of our method in diagnosis and prognosis of pneumoconiosis in CT screening.

In this paper, according to the flood risk-influencing hazard of disaster-formatire factors, the stability of hazard-pregnant environment and the vulnerability of hazard bearing body, the indexes of precipitation, runoff, river, terrain, population and economy are considered. Taking, Henan Province as the focus area, and county as the administrative unit, both the hazard assessment map and the vulnerability assessment map of the flood disaster are acquired based on GIS and AHP integrated method. Finally, the comprehensive hazard evaluating map of the flood disaster was drawn. The case study shows that the GIS-based category model is effective in flood risk zonation. Therefore the paper has a certain theoretical and practical significance.

One of the key issues in establishing an optical fiber sensing system based on fiber Bragg gratings (FBGs) is the selection of a suitable wavelength shift detection scheme in terms of the performance it offers. By use of a compact Fabry-Perot (F-P) tunable filter, the Bragg wavelength variation can be detected with a relatively high speed and satisfying resolution. In this paper, a dynamic strain sensing system based on F-P tunable filter is described, and the F-P tunable filter is demonstrated to have a significant impact on the system. The relationship between the collected spectrum of grating and the 3-dB bandwidth of the F-P tunable filter is discussed. The optimum 3-dB bandwidth of the F-P tunable filter for most FBGs is obtained. It is exhibited in this paper that the demodulation precision and sensitivity of the strain sensing system is influenced by the nonlinearity between the transmission wavelength of the F-P tunable filter and the drive voltage. The drive voltage is rectified using interpolation algorithm. The experimental results illustrate that the average error and the maximum error of the transmission wavelength are decreased by 96.4% and 80.9% respectively. The strain sensitivity of the optimized system is below 3μe. The error between the practical strain value demodulated by the system and theoretical value is below 5%.

This paper aims at proposing a modified algorithm based on spectrum adjusting. The theoretical analysis of the error between the real light source spectrum and the Gaussian spectrum is presented. The hardware of the demodulation system is introduced, including the coupler, collimation lens, volume phase grating, focus lens, CCD array, A/D card, and PC. The modified algorithm will adjust the interferometric spectrum of the sensor by getting rid of the effect of the light source spectrum. Experiment was carried out to test the performance of the demodulation system. It can be found from the result that the algorithm has improved the accuracy of the demodulation system significantly. The demodulation accuracy for the strain sensor is better than 0.5 microstrain. Keywords: fiber optic sensor, Fabry-Perot, demodulation algorithm, spectrum 1. INTRODUCTION Fiber optic sensors have been rapidly developed in the past three decades. Now they are havi ng a fast increasing market share in the world sensor market [1, 2]. Fiber optic Fabry-Perot (F-P) sensor is one of the most well developed types of fiber optic sensor. It has small size, which makes it can be used as ‘point sensing’ element in many cases. Fiber optic F-P cavity is made by inserting two fiber ends in to one capillary. As the fiber end has a very low reflectivity, such fiber optic cavity is called as ‘low-finesse Fabry-Perot cavity’ [3]. By using a white light source, the cost of the sensing system can be greatly reduced. But, a white light source usually has a Gaussian spectrum, which will induce wavelength peak measurement error in a wavelength demodulation system. This error has been analyzed, but no improved algorithm has been presented. In this paper, we pr esented a fiber optic F-P sensor demodulation system using a algorithm of output spectrum adjusting. The demodulation system includes the coupler, collimation lens, volume phase grating, focus Lens, CCD array, A/D card, and PC. The principle of the fiber optic F-P sensor is presented and the improved algorithm is introduced. The experiment shows the improved algorithm has improved the resolution of the demodulation system.

Flattened ASE fiber sources with C+L bandwidth(1520-1620nm) are attractive. Long period fiber gratings (LPFG) have the characteristics of band-stopped, which can be used to flatten the spectrum of amplified spontaneous emission (ASE) light source. In this paper, spectrum flattening of ASE light source covering C-band and L-band based on a long period fiber grating is studied. As a flattening filter, LPFG is often placed in the end of the output port. The results in this paper show that the placed position of LPFG has great influence on the spectrum flattening of ASE light source. Output spectrum measured of filtered ASE source with the LPFG at different position is given, and the detailed theoretical analysis to explain the experimental results is followed. In the dual-stage double-pass structure, based on a long period fiber grating and two 980 nm high power semiconductor lasers, high power and ultra bandwidth ASE fiber source has been gained. The source has a bandwidth of 77 nm (1525.5 ~1602.5 nm) with ±1.6 dB ripple and 42 mw of output power.

A nonlinearity correction using ellipse fitting technique based on orthogonal polarized laser interferometer is proposed in this paper. In this paper, characteristics of four-channel output signals based on polarized Michelson laser interferometer are studied. The orthogonal signal's non-orthogonal error which is caused by temperature disturbance and low frequency vibration noise is compensated. Besides, a new algorithm of demodulating small phase signal is proposed. Low frequency vibration signal demodulation system based on DSP technique is constructed. It proposed an ellipse fitting algorithm based on Least-squares theory. This algorithm can achieve correction error of less than ±0.3%. System's real-time measurement capability and its resolution can be improved.

Based on Jones matrices theory, the error source and action mechanism of polarized interferometer using four-channel orthogonal signals in nanometer level measurement are researched. It opens a door for selecting optical components, adjusting light set-up and compensating error.The mechanism of nonlinear errors and the variance law of nonlinear errors in laser interferometer, which is caused by nonideal factors of 1/4 wave plates or 1/2 wave plate or all of them, based on polarized phase-shift technology. In this paper, every single error on the polarized interferometer is discussed with the isolation of each wave plate, so that the character of nonlinear error will be reached with composite error. In the experiments, difference delay angle error of two 1/4 wave plates and location angle error is -5°∼5°in interferometer. The aim of this paper is to realize the mechanism of nonlinear errors and the varying rule of nonlinear errors in laser interferometer. All above provide error remove or compensation for laser interferometer in nanometer level measurement with theoretical foundation and search after application.

In the article, results of simulation and laboratory research of designed voltage transformer are described. In the first part of the paper voltage transformer model is presented. Second part of the article is dedicated to voltage transformer model errors simulation. In the last section of this paper verification of simulation results is described. Correct simulation of the voltage transformer enables shorten design time and reduction of cost production.

In sonar imaging for seafloor remote sensing, research activities are more and more oriented on the use of data fusion approaches. Nowadays, it is well established that using sonar images, the Digital Elevation Maps (DEMs), can be generated by exploiting either the amplitude information or the phase information of the acoustic signal. In this paper, the main interest consists on the generation of a complete Digital Elevation Map (DEM) by the use of a data fusion approach of two existing DEMs issued from two different techniques. The aim of the proposed approach is to elaborate a general interpretation system that coherently links works on data selection and fusion leading to improve DEMs generation and to exploit it in the seafloor remote sensing applications (particularly for the inhomogeneous scenes with a variety terrain). In this paper, shape from shading and the interferometry techniques are considered. Then, the manner of the DEMs fusion proposed, has been based on fuzzy logic and some fuzzy propositions, which defined using experts a priori knowledge source. This promising idea enables information to be managed through the consideration of the imprecision and ambiguity information and the benefit provide by the injection of the a priori knowledge in the decision taken system.

This paper explores the development of an idea conceived a number of years ago for the integration of three diverse technologies into a system capable of supporting a wide variety of applications. The concept of Virtual Geographic Information System (VGIS) was developed in the early 1990's even though no technology base existed that would support real time implementation of the idea. The VGIS concept grew out of the integration of Geographic Information Systems (GIS), Remote Sensing (RS), and Visualization (Viz) into a comprehensive tool that is now used at Georgia Tech in terrain analysis, environmental analysis, weather radar visualization, weather model understanding, situational visualization for emergency response, etc. The implementation of the concept culminated in the development of a system called the Georgia Tech Virtual GIS System (GTVGIS). This paper will discuss the evolution of the system, its applications at Georgia Tech, and the new directions and commercial utilization of similar concepts.

There is currently a need for compact actuators capable of producing large deflections, large forces, and broad frequency bandwidth. In all existing transducer materials, large force and broadband responses are obtained at the price of small displacements and methods for transmitting very short transducer element motion to large deformations need to be developed. This paper addresses the development of a hybrid actuator which provides virtually unlimited deflections and large forces through magnetorheological (MR) flow control and rectification of the resonant mechanical vibrations produced by a magnetostrictive Terfenol-D pump. The device is a self-contained unit which produces large work output concurrently with stiffness and damping control, and is compact and self-locking when unpowered. To increase the output force, hydraulic advantage is created by implementing a driven piston diameter that is larger than the drive piston. Since the pump operates at high speeds in the low kHz range, a fast-acting MR fluid valve is required. The paper presents a four-port MR fluid valve in which the fluid controls its own flow while carrying the full transducer load. A prototype two-port valve was designed and constructed. Experimental measurements at various pressure levels are presented which demonstrate the new valve concept.

This paper discusses some questions about transition radiation effect in foil stack, analyses stimulated amplification of optical wave in foil stack. In this paper, authors research two possible models about x-ray or soft x-ray FEL(free-electron lasers). First model is transition radiation effect and circulating crystal resonator apply to x-ray EEL, second model is to produce x-rayEEL by means of high-energy electron beam, undulator and circulating crystal resonator.Key words:transition radiation, stimulated amplification of optical wave,undulator, circulating resonator,free-electron lasers. 1. INTRODUCTION A conventional FEL is difficulty to produce short wavelength laser similar to x-ray laser. One problem is the optical wavelength X is restricted by the period Xw and the field strength Bw Of wiggler magnetic field. Another problem is the low reflectance of resonator mirror for x-ray. In this paper, authors discuss two novel models of x-ray FIlL. In first model, a circulating resonator with crystal reflectingmirror instead of Fabry-Perot resonator in conventional FEL and the proper periodic foil stack is inserted in the wiggler

All current concepts for the NGST are innovative designs which present unique systems-level challenges. The goals are to outperform existing observatories at a fraction of the current price/performance ratio. Standard practices for developing systems error budgets, such as the 'root-sum-of- squares' error tree, are insufficient for designs of this complexity. Simulation and optimization are the tools needed for this project; in particular tools that integrate controls, optics, thermal and structural analysis, and design optimization. This paper describes such an environment which allows sub-system performance specifications to be analyzed parametrically, and includes optimizing metrics that capture the science requirements. The resulting systems-level design trades are greatly facilitated, and significant cost savings can be realized. This modeling environment, built around a tightly integrated combination of commercial off-the-shelf and in-house- developed codes, provides the foundation for linear and non- linear analysis on both the time and frequency-domains, statistical analysis, and design optimization. It features an interactive user interface and integrated graphics that allow highly-effective, real-time work to be done by multidisciplinary design teams. For the NGST, it has been applied to issues such as pointing control, dynamic isolation of spacecraft disturbances, wavefront sensing and control, on-orbit thermal stability of the optics, and development of systems-level error budgets. In this paper, results are presented from parametric trade studies that assess requirements for pointing control, structural dynamics, reaction wheel dynamic disturbances, and vibration isolation. These studies attempt to define requirements bounds such that the resulting design is optimized at the systems level, without attempting to optimize each subsystem individually. The performance metrics are defined in terms of image quality, specifically centroiding error and RMS wavefront error, which directly links to science requirements.

In this paper a CuBr pulsed laser ((lambda) equals 510.6 nm and 578.2 nm) having an average output power of 10 W and efficiency (2,5%) is presented. Owing to a considerably lower operating temperature (560 degrees Celsius) CuBr laser becomes an alternative for more widely used conventional Cu laser (with operating temperature 1500 - 1600 degrees Celsius) in such applications where the required laser output power is lower than 50 W. Examples for such applications, mainly for high precision laser machining in electronic are presented in this paper.

This paper describes Hardware-In-The-Loop simulation as practiced at the U.S. Army Missile Command Advanced Simulation Center (ASC) located at Redstone Arsenal, Alabama. An overview of several of the simulators operated at the ASC is followed by a discussion of the role of simulation in the missile system development process. The paper concludes with a summary of the Verification and Validation methodology employed for a typical hardware-in- the-loop simulation.

The complexity and performance characteristics of weapon systems under development by the Ballistic Missile Defense Organization (BMDO) require an integrated test approach that spans all levels of testing. Flight testing of ballistic missile interceptors is limited by the complexity and costs of the exercises and are constrained by inherent restrictions imposed by test ranges. While flight testing remains an essential part of ballistic missile interceptor test programs, other test methods must be utilized to fully characterize system operational characteristics. The BMDO uses a test concept which employs specialized facilities to address critical aspects of the ballistic missile defense (BMD) engagement process. The facilities are used during all phases of the acquisition life cycle, accommodating test articles ranging from early prototype subsystems to integrated production-like systems. Individually, these facilities characterize the performance of the specific unit under test. Collectively, these facilities span the BMD engagement process from target detection through kill assessment. Test results are consolidated to characterize the performance of the integrated system. In this manner, the performance of the system is characterized throughout its potential performance envelope. This paper discusses the role and contribution of infrared space-based surveillance and kinetic kill interceptor hardware-in-the-loop (HWIL) facilities in BMD test programs. An overview of BMDO HWIL test policy and sponsored facilities is presented. This paper examines the relationship between BMDO sponsored facilities in terms of inputs required to support HWIL tests and HWIL outputs available to support other tests. Issues pertinent to planning and executing a successful HWIL program are also discussed.

The paper gives a set of new low power radio propagation models in the picocell environments suitable to some urban and rural conditions in China. A number of propagation measurements was taken by the authors using two antenna height of 3.2 m to 7.5 m at frequency 900 MHZ. Test settings were chosen in rural open areas, suburban streets, and urban streets, crossroads and overbridges in order to study propagation in variety of environments. Based on the obtained data in different environments, this paper takes the further steps to discuss the variations of signal strength with distance that have distinct near and far regions separated by a breakpoint and the effect of antenna height and type by analyzing the two ray model, and then gives a new propagation model, which was proved well-fitted to the measured results in some places. Moreover, this model was applied to make the radio propagation prediction for CT2 Campus Network, which is now running well. This also shows the practicality and reliability of the model in Chinese environments. Up to present, the measurement database has been established and a CAD software package which can predict the radio coverage area for rural and urban in China is going to be finished.

The train energy model (TEM), a general train simulator developed at the Association of American Railroads, is widely used in the railroad industry. Recently, a new train controller, the general automatic train-controller (GAT), has been developed for TEM. In the GAT, the 'intelligence' or 'expertise' is a set of 'if-then' train-handling rules in an external file. The expert system for train control presented in this paper is a slightly simplified version of the GAT. The main thesis of this paper is: simple, unchained rules are adequate for complex train control. Thus, an 'inference engine' using forward chaining is not required.

This paper describes a simple and low cost transceiver for indoor wireless LAN system to be operated in 60 GHz for ultra-high speed data (e.g. 156 Mbps) transmission, along with design of system parameters such as frequency selection, radio link parameters featuring very low RF power of 10 mW suitable to MMIC performances and high gain antennas. Without using route diversity and adaptive delay equalizers making up for shadowing and multipath reflection of RF signals, new layout of hub and user stations and line-of-sight transmission scheme are adopted. In addition, partially applied radio absorber helps effectively to reduce the undesired co-channel interference signal to the neglectful level, which system is named minimum delay spread (MDS0 local area network (LAN). This paper also presents the idea of effective applying absorber on ceiling which is derived from simulation and some useful measured data of absorbing construction materials, and presents main features of developed MMIC chip set workable in 60 GHz.

In this paper further discussions on some new methods proposed in an earlier paper on phase stepping interferometry is detailed. These studies reveal that certain algorithms are more sensitive to miscalibration and nonlinearity and can be better candidates to detect the presence of phase shifter miscalibration or nonlinearity. A simplified approach to the understanding of the error and its reduction/elimination in phase shifting interferometry are also presented.

The practical application ofElectronic Holography requires the use offiber optics. The need ofemploying coherent fiber optics imposes restrictions in the efficient use oflaser light. This paper proposesa new solution to this problem. The proposed method increases the efficiency in the use ofthe laser lightand simplifies the interface between the laser source and the fiber optics. the paper will present the theorybehind the proposed method. A discussion ofthe effect ofthe different parameters that influence theformation ofinterference fringes is presented. Results that can be achieved and limitations are given. Anexample of application is presented. 1. INTRODUCTIONElectronic Speckle Interferometry,(ESPI) as it is commonly referred in the literature, or also Electronic Holography, is an image plane holographic method. Videcom tubes or CCD arrays are used torecord holographic images. The recording process is identical to conventional holography except that therecording medium has a very low spatial resolution compared to films or plastic recording media. The

In any electron optical system, compensating for the lens aberrations is the key to improving the spatial resolution. Ofall the dominant aberrations, only the spherical aberration and chromatic aberration continue to limit the performance ofmicroscopes. In the plane ofthe Gaussian image, these aberrations are given by: spherical aberration: o = Cs a chromatic aberration: o C a oV/V, Where C5 and C are the coefficients of spherical aberration and chromatic aberration, respectively. a is the divergent angle ofthe electron path with respect to the axis. 8V is the energy spread ofthe electron source and V is the electron energy, in eV. Several systems, such as a magnetic sextupole and quadrupole configuration [1,2], have been proposed to correct these aberrations. Recently, Crewe proposed a simple "mirror corrector" system for correcting them by reversing their coefficient signs [3]. However, it will be some time before any ofthese proposed systems will prove to be applicable on a practical basis. In the meantime, it may be profitable to concentrate on how to choose the best operating parameters for any existing system, in order to optimize the resolution. The resolution of a system is calculated by combining the effect ofthe dominant aberrations with the effects of diffraction and defocus: diffraction: 8d 0.6 lAJa, defocus: C5 a2c where X =(15O/V)' A isthe electron wavelength, and c is the defocus parameter, defined in this paper as 0 at the Gaussian image plane and 1 at the marginal plane. The optimum resolution is achieved by choosing a and to attain the minimum combined aberration. Conventionally, a is chosen to be the largest possible divergent angle, which is the angle determined by the aperture size. This considers only the worstcase situation and ignores the fact that the path of the optical ray is critically dependent on a. Simply because there are some large divergent angles does not mean necessarily that those contributions dominate the formation of the electron probe. Ignoring the possible range of a results in the loss of all the details of the probe pattern. This prevents one from deriving any information about the resolution from the internal details of the probe. Calculations based on a single, maximum value of a can be expected to be conservative and to underestimate the power of the microscope. Recently, Rempfer and Mauck investigated the interior intensity pattern of an electron probe by ray tracing the path ofeach individual electron[4J. Their results showed that the intensity distribution ofthe probe varied greatly in different defocus planes, and was extremely nonuniform in every plane. This paper presents a study in which a numerical simulation is used to determine the probe pattern resulting from the spherical aberration, chromatic aberration, source size, and defocus. The probe pattern in different defocus planes is then convoluted with two types of simulated samples in order to directly investigate the possible resolution. The results show that the conventional calculations ofresolution may not be appropriate for all circumstances. Also, the optimal operational parameter can be very different, depending on what information the operator wishes to get from the microscope.

In most artificial neural network applications, (e.g. pattern recognition) if the dimension of the input vectors is much larger than the number of patterns to be recognized, generally, a one- layered, hard-limited perceptron is sufficient to do the recognition job. As long as the training input-output mapping set is numerically given, and as long as this given set satisfies a special linear-independency relation, the connection matrix to meet the supervised learning requirements can be solved by a noniterative, one-step, algebra method. The learning of this noniterative scheme is very fast (close to real-time learning) because the learning is one-step and noniterative. The recognition of the untrained patterns is very robust because a universal geometrical optimization process of selecting the solution can be applied to the learning process. This paper reports the theoretical foundation of this noniterative learning scheme and focuses the result at the optimal robustness analysis. A real-time character recognition scheme is then designed along this line. This character recognition scheme will be used (in a movie presentation) to demonstrate the experimental results of some theoretical parts reported in this paper.

In this paper, with ideal power control and ideal interleaving, the optimization between the processing gain and the coding gain of a constant bandwidth direct-detection spread-spectrum system operating in the environment of Rician fading channel is presented. The BPSK modulation is considered, and binary BCH codes are employed to illustrate the benefit with the optimum design. Also, optimization of the code rate for this channel is presented and discussed numerically. The results of this paper may be a useful guideline for spread spectrum system design.© (1995) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.

This paper reviews the recent progress towards III-nitride in tersubband devices based on quantum wells. We first present recent achievements in terms of GaN-based quantum cascade detectors operating at near-infrared wavelengths. We show that these devices are intrinsically extremely fast based on femtosecond time-resolved measurements of the photocurrent. The design of III-nitride quantum cascade detectors, which relies on the engineering of the internal electric field, is flexible enough to allow for two-color detection. We finally discuss the potential of III-nitride intersubband devices in the THz frequency domain a nd present the recent observ ation of THz absorption using low aluminium content AlGaN/GaN step quantum wells. Keywords: III-nitride semiconductors, intersubband transitions, optoelectronic devices, quantum cascade detectors, quantum wells. INTRODUCTION Intersubband photonics (ISB) have emerged within the last 25 years and led to a number of fascinating control-by–design devices relying on the quantum engineering of electron confinement in semiconductor quantum wells (QW) or quantum dots (QD) [1]. One famous example is the quantum cascade laser (QCL), which was invented in the mid-90’s at Bell Laboratories [2]. This device relies on the repetition of multiple quantum well (MQW) active regions where ISB light emission takes place and injector/extractor regions to transfer electrons from one period to the other. The ISB emission wavelength can be tuned in a wide spectral range simply by adjusting the layer thickness. Using materials such as GaAs/AlGaAs, InGaAs/AlInAs or antimonides, the operation wavelength of ISB devices such as the QCLs can be tuned from the mid-infrared to the THz spectral range. Operation at short wavelengths is limited by the available conduction band offset and by the material transparency. Thanks to the progress achi eved in terms of epitaxial growth of ultrathin layers, III-nitride semiconductors (GaN, AlN, InN and their alloys) have emerged within the last ten years as excellent materials for ISB photonics devices in the near-infrared spectral range and in particular in the 1.3-1.55 µm wavelength window used for fibre optics telecommunications. Not only they are transparent in a wide spectral region (360 nm to 13 µm for GaN) but the conduction band offset prov ided by their heterostructures is quite large, of the order of 1.75 eV for GaN/AlN [3]. In contrast to InAs/AlSb materials, which also exhibit a large conduction band discontinuity, the remote valleys of GaN lie very high in energy (>2 eV above the + point [4]), offering the potential for ISB light emitting devices at record short near-infrared wavele ngths. Another specificity of nitride materials is the large longitudinal-optical (LO) phonon energy (92 meV for GaN) as well as the presence of huge internal fields induced by the spontaneous and piezoelectric polarizatio ns along the c axis inherent to their wu rtzite structure. The presence of these

Criminal activity in virtual worlds is becoming a major problem for law enforcement agencies. Forensic investigators are becoming interested in being able to accurately and automatically track people in virtual communities. In this paper a set of algorithms capable of verification and recognition of avatar faces with high degree of accuracy are described. Results of experiments aimed at within-virtual-world avatar authentication and inter-reality-based scenarios of tracking a person between real and virtual worlds are reported. In the FERET-to-Avatar face dataset, where an avatar face was generated from every photo in the FERET database, a COTS FR algorithm achieved a near perfect 99.58% accuracy on 725 subjects. On a dataset of avatars from Second Life, the proposed avatar-to-avatar matching algorithm (which uses a fusion of local structural and appearance descriptors) achieved average true accept rates of (i) 96.33% using manual eye detection, and (ii) 86.5% in a fully automated mode at a false accept rate of 1.0%. A combination of the proposed face matcher and a state-of-the art commercial matcher (FaceVACS) resulted in further improvement on the inter-reality-based scenario.

In this paper, we introduced the advantages of Vertical Light emitting diode (VLED) on copper alloy with Si-wafer level packaging technologies. The silicon-based packaging substrate starts with a dou-ble-side polished p-type silicon wafer, then anisotropic wet etching technology is done to construct the re-flector depression and micro through-holes on the silicon substrate. The operating voltage, at a typical cur-rent of 350 milli-ampere (mA), is 3.2V. The operation voltage is less than 3.7V under higher current driving conditions of 1A. The VLED chip on Si package has excellent heat dissipation and can be operated at high currents up to 1A without efficiency degradation. The typical spatial radiation pattern emits a uniform light lambertian distribution from -65° to 65° which can be easily fit for secondary optics. The correlated color temperature (CCT) has only 5% variation for daylight and less than 2% variation for warm white, when the junction temperature is increased from 25°C to 110°C, suggesting a stable CCT during operation for general lighting application. Coupled with aspheric lens and micro lens array in a wafer level process, it has almost the same light distribution intensity for special secondary optics lighting applications. In addition, the ul-tra-violet (UV) VLED, featuring a silicon substrate and hard glass cover, manufactured by wafer level pack-aging emits high power UV wavelengths appropriate for curing, currency, document verification, tanning, medical, and sterilization applications.

The development and application of nitride-based light-emitting diodes (LEDs) is hindered by the low hole conductivity of Mg-doped layers. As an alternative, polarization-induced hole doping of graded p-AlGaN layers was recently demonstrated. Using previously manufactured 440nm LEDs as device examples, this paper evaluates the effect of polarization doping by advanced numerical device simulation, both for Ga-face and N-face growth. Recently published material parameters are employed in the simulation, including new data for the Auger coefficients. The simulations reveal that Auger recombination is the main carrier loss mechanism in these devices, electron leakage seems to exert a much smaller influence on the internal quantum efficiency. The importance of internal physical mechanism is studied in detail, including the Poole-Frenkel field ionization of Mg acceptors, which is commonly held responsible for polarization doping effects. Surprisingly, we find that the field ionization inside the graded p-AlGaN layers is not stronger than in conventional electron blocking layers.

The Clouds and Earth Radiant Energy System (CERES) Flight Model 5 (FM5) instrument is scheduled to be launched this year aboard the NPP spacecraft in order to continue the Climate Data Record for Earth radiation budget. CERES data will be used together with measurements from the Visible Infra-red Imager Radiometer Suite (VIIRS) to compute cloud information for each CERES pixel. Knowledge of the point response function (PRF) of CERES is essential to accurately align these data sets. The Radiation Calibration Facility at Northrop Grumman includes the PRF Source, an optical devise for measuring the PRF. This paper presents the analysis of these tests and the resulting PRF for each of the three channels.

Unmanned aerial vehicles (UAVs) capture real-time video data of military targets while keeping the warfighter at a safe distance. This keeps soldiers out of harm's way while they perform intelligence, surveillance and reconnaissance (ISR) and close-air support troops in contact (CAS-TIC) situations. The military also wants to use UAV video to achieve force multiplication. One method of achieving effective force multiplication involves fielding numerous UAVs with cameras and having multiple videos processed simultaneously by a single operator. However, monitoring multiple video streams is difficult for operators when the videos are of low quality. To address this challenge, we researched several promising video enhancement algorithms that focus on improving video quality. In this paper, we discuss our video enhancement suite and provide examples of video enhancement capabilities, focusing on stabilization, dehazing, and denoising. We provide results that show the effects of our enhancement algorithms on target detection and tracking algorithms. These results indicate that there is potential to assist the operator in identifying and tracking relevant targets with aided target recognition even on difficult video, increasing the force multiplier effect of UAVs. This work also forms the basis for human factors research into the effects of enhancement algorithms on ISR missions.

In this paper, we describe a theoretical model, which allows simulating speckle pattern in an imaging system and its detection by an image sensor with a limited number of pixels. This simulation tool is based on the Fourier Optics theory. Preliminary tests show a very good agreement between simulations and experiments. We have demonstrated experimentally and theoretically that sub-micrometer displacement resolution is possible by means of the crosscorrelation of speckle patterns, over a range limited to half of the field-of-view of the imaging system.

Energy exchange between the electrons and phonons is particularly important to electron transport, and understanding this process will be vital for the realization of future graphene-based electronics. Epitaxial growth is a very promising approach for practical applications, as it has the ability to prepare graphene on a large scale and supported on a substrate. However, epitaxially grown graphene is highly inhomogeneous, with variations in the sample thickness occurring over length scale of a few micrometers. To pave the road for electronic devices based on epitaxial graphene, characterization methods with high spatial resolution are required. In this paper, we describe transient absorption microscopy as a novel tool to characterize graphene, and to interrogate the charge carrier dynamics. The carrier cooling exhibited a biexponential decay that showed a significant dependence on carrier density. The fast and slow relaxation times were assigned to coupling between electrons and optical phonon modes and the hot phonon effect, respectively. The limiting value of the slow relaxation time at high pump intensity reflects the lifetime of the optical phonons. Significant spatial heterogeneity in the dynamics was observed due to differences in coupling between graphene layers and the substrate. This is attributed to differences in coupling between the graphene and the substrate. These results point to transient absorption microscopy as a potentially important tool for characterizing graphene.

Free viewpoint television (FTV) is a new technology that allows viewers to change view angles freely while watching TV programs. FTV requires a strong support of multi-view video codec (MVC), such as H.264/MVC defined by Joint Video Team(JVT). In this paper, we propose an FTV system which can produce videos as perceived in any view angles based on limited number of viewpoint videos decoded from H.264/MVC bitstreams. In this system, the decoded disparity vectors and motion vectors are diffused to produce smooth disparity fields for virtual view reconstruction. Decoded residue data under motion compensation are used as a match criterion. The proposed system not only greatly reduces the computation burden in creating FTV, but also improve the synthesized viewing quality due to the use of quarter pixel precision of H.264.

Microscopes typically use a single color illumination source and the intensity of it can be varied depending on the application. They are used to observe various specimens which are usually stained to highlight the objects of interest. Automatic methods for identification of diseases from these specimens have been developed recently. The stains result in different colors and white illumination source may not offer the best contrast in all cases. Further, the staining process does not always result in the same color owing to the changes in the pH of the buffer used. This paper overcomes these problems by using a varying color illumination source for microscopes to offset the variations in the stain and ensures that the best contrast is achieved under all conditions. The results of segmentation of nucleus of White Blood Cells under varying color illuminations are shown as an example.

This paper proposes a robust ear identification system which is developed by fusing SIFT features of color segmented slice regions of an ear. The proposed ear identification method makes use of Gaussian mixture model (GMM) to build ear model with mixture of Gaussian using vector quantization algorithm and K-L divergence is applied to the GMM framework for recording the color similarity in the specified ranges by comparing color similarity between a pair of reference ear and probe ear. SIFT features are then detected and extracted from each color slice region as a part of invariant feature extraction. The extracted keypoints are then fused separately by the two fusion approaches, namely concatenation and the Dempster-Shafer theory. Finally, the fusion approaches generate two independent augmented feature vectors which are used for identification of individuals separately. The proposed identification technique is tested on IIT Kanpur ear database of 400 individuals and is found to achieve 98.25% accuracy for identification while top 5 matched criteria is set for each subject.

In response to an Announcement of Opportunity for new instrumentation for the Gran Telescopio Canarias (GTC) issued on October 2009, an international team led by the University of Florida and composed of scientists and engineers from 8 institutions in 3 countries submitted a proposal for building a highly powerful instrument within the required envelope and budget. The MIRADAS instrument will be a common user NIR multi object spectrograph equipped with a sophisticated multiplexing system (MXS) able to deliver spectral resolutions of R~20,000 in the wavelength range from 1 to 2.5 microns for up to 20 objects simultaneously sparsely distributed over a field of regard of 5 arcmin in diameter. In this paper, we summarize the main instrumental features of the proposed instrument which is under review by the GTC Project Office.

This paper presented signal demodulation scheme of the laser vibration interferometer system using for measurement of low-frequency vibration. Based on principle of phase generated carrier (PGC) modulation and virtual instrument technology, laser vibration signal demodulation on software and hardware platform were established. Taking the PCI6221 multi-function data acquisition device as the core of hardware circuit, real time data acquisition of reference waveform generation and the signal for measurement was realized. Digital PGC algorithm was established by using LabVIEW software workbench, and then vibration signal real time demodulation was realized. The experiment results indicate that the PGC signal demodulation scheme based on virtual instrument technology reduced drift and noise by traditional analog PGC hardware circuit such as analog multiplier and differentiator, enhanced accuracy of signal demodulation, improved system Signal-to-Noise. High accuracy measurement of the low-frequency vibration signals ranging from 10~200Hz comes true, the measuring resolution is better than 0.5nm, and the dynamic range is 110dB.

Multi-mode Airborne Digital Camera System (MADC) was developed by Institute of Remote Sensing Applications and Shanghai Institute of Technical Physics in 2006. The system is enhancing and optimizing further now. It could realize three modes of wide field, multispectral, and stereophotography based on three 4K*4K CCD digital cameras in the course of taking aerial photography. Several finished aerial experiments have already demonstrated that the system has good performance for aerial photography; both the software and the hardware of MADC could work stably and reliably. Multispectral mode is a popular imaging way in airborne remote sensing. It can obtain multi-bands remote sensing images by using several digital cameras synchronously. The multispectral images can make use for various remote sensing applications, such as environment monitoring, resource researching, military use, and so on. In some special conditions, images which get by using less than 10nm bandwidth narrowband filters can be treat as hyperspectral images; so that we can consider the multispectral imaging way is a new approach for hyperspectral bands selection and data acquisition. In this paper, we will mainly discuss the following questions for the multispectral mode of MADC: the design principle, the basic arithmetic or model, the installation mode, the corresponding aerial experiments, the application fields and the ways of multitspectral images processing. At the same time, some important accessorial devices of MADC are also introduced. The point and conclusion will be received based on the practice installation, operation, ground and aerial experiments.

This paper describes the ground target detection, classification and sensor fusion problems in distributed fiber seismic sensor network. Compared with conventional piezoelectric seismic sensor used in UGS, fiber optic sensor has advantages of high sensitivity and resistance to electromagnetic disturbance. We have developed a fiber seismic sensor network for target detection and classification. However, ground target recognition based on seismic sensor is a very challenging problem because of the non-stationary characteristic of seismic signal and complicated real life application environment. To solve these dificulties, we study robust feature extraction and classification algorithms adapted to fiber sensor network. An united multi-feature (UMF) method is used. An adaptive threshold detection algorithm is proposed to minimize the false alarm rate. Three kinds of targets comprise personnel, wheeled vehicle and tracked vehicle are concerned in the system. The classification simulation result shows that the SVM classifier outperforms the GMM and BPNN. The sensor fusion method based on D-S evidence theory is discussed to fully utilize information of fiber sensor array and improve overall performance of the system. A field experiment is organized to test the performance of fiber sensor network and gather real signal of targets for classification testing.

Two-core fiber is a specially designed fiber which contains a pair of parallel fiber core surrounding a cladding with diameter 125μm. A multi-parameters measurement technique that uses a two-core fiber as the sensing element has been proposed and demonstrated in this paper. The theory and the structure design are also introduced. The two-core fiber acts as a two-beam interferometer, in which phase differences is a function of curvature, and the twisting angle in the plane containing the cores results in the shift of the far-field interferometric fringe pattern. This sensor can be used to inspect the structural health monitoring, the measuring angle and the distinguishing direction. Compared to the traditional multi-beam interferometer, this sensor has the such characteristics as small size, good interference, high definition and steady fringe pattern. It does not need considering the effect of the environment temperature. A low-coherence laser diode at wavelength 650nm illuminating the two-cores and the interferogram pattern in the far-field is recorded by a CCD camera. The model of two-core fiber sensor has been established theoretically. The relationship between the far-field fringe pattern intensity distribution and the changes due to the radius of the curvature and the twisting angle are given, and the experimental results also confirmed this.

The techniques used in dynamic detection of airfield lighting intensity are introduced in this paper. These techniques can take place of the old method of checking all manually, and the system can detect the lights intensity online quickly and exactly, so as to fmd out the light faults and ensure the safety of planes' taking off, landing and slipping. The system uses a car with a string of sensors which have been cosine calibrated and v(X) calibrated to detect the light intensity. When the car is moving, the sensors can detect the lights' horizontal section. To accurately measure the distance from the measured aerodrome assistance light to the moving car, and then calculate the light intensity and protract the iso-candela curve, the Doppler ranging radar system is used. To guarantee the dependability of the system and the measurement precision, a video monitoring and guiding system is used to assure the car to run along the airfield lights line, then light orientation sensors are used to eliminate the radar's cumulating errors. The experiment indicates that this system is feasible and has high detecting precision.

In this paper, a packaged erbium-doped fiber amplifier (EDFA) is integrated into a fiber ring to form an erbium-doped fiber ring (EDFR) laser which is applied to measure the particle size based on the self-mixing Doppler effect. A detailed analysis is addressed to introduce the measurement principle, and the obtained results demonstrate that the diameter of the Brownian particles in water can be measured by detect the variations of the intensity and frequency of the fiber laser. This technique can be used in biology, process engineering and chemistry.

Based on the transfer matrix method, the reflection spectra of strained chirped fiber gratings are analyzed theoretically. Chirped fiber gratings are fabricated by etching uniform FBGs with HF. The cross section of the chirped FBG has a gradient variation along the axis. The full width at half maximum of the refection spectra of the chirped fiber grating can reach 0.4-0.75nm. When axial stress is applied on the chirped FBG, the bandwidth can reach 5nm. The sensitivity of the bandwidth to stress can achieved 20% higher than that of uniform fiber Bragg gratings. The relationship of the bandwidth and the imposed force, as well as the one between the reflection power and the force, derived from the coupled mode theory, will also be tested in the experiments, which has been shown in this paper.

It is well known that as a measurement device, Sagnac fiber interferometer has the advantages of high measuring sensibility and strong antijamming ability. However, it is precisely because of the high sensibility, the measured change range of sensed quantities is usually very small. And also because of the strong antijamming ability, the fiber of Sagnac interferometer can not be used as a sensor. The reason is that the sensed signal well be eliminated by the signal cancellation effect between the two directions in Sagnac interferometer like the disturbance signal. This paper presents a novel Sagnac fiber sensor. It is added two devices into the common Sagnac fiber loop, one is the phase compression device and another is the birefringent fiber sensor. The phase compression device consists of a time delay fiber and a piezoelectic ceramic twisted around by Sagnac fiber. This device can realize the phase compression by which the measured range of sensed quantities is widely extended. The birefringent fiber sensor consists of a short section of high birefringent fiber. The method of adding the birefringent fiber sensor is selecting suitable position on Sagnac fiber loop and breaking off the fiber, then melting and linking the two break surfaces with the short section of high birefringent fiber. Not like the common fiber, there is not cancellation effect on the birefringent fiber. So the Sagnac interferometer can become a sensor. This kind of Sagnac fiber sensor has the advantages of high measuring precision, wide measured range, strong antijamming ability and simple structure.

As novel passive optical components, fiber gratings have a comprehensive prospect in optical communication and sensing systems, due to their excellent optical properties. Blazed fiber Bragg grating, an important member of fiber gratings, because of its special structure, not only has all properties of fiber Bragg grating, but also has its own unique properties. With the fiber sensitivity enhanced and the technology of fabrication fiber grating improved, blazed fiber Bragg grating with an excellent character comes true, which have been used in the area of gain flatten, sensing system and wavelength demodulation. The sensing theory of blazed fiber Bragg grating is presented in the paper. Theoretical and Experimental research on its temperature sensing characteristic, strain sensing characteristic have been taken. The blazed fiber Bragg grating has the same temperature sensing and strain sensing characteristic as fiber Bragg grating. The temperature sensitivity experiments of the grating have been studied. By packaging fiber gratings with a special type of polymer, the experiments indicate that the temperature sensitivity to seven times.

In this paper, the glass microsphere co-doped Er 3+ /Yb 3 + was fabricated. Many regularly spaced, sharp peaks appeared in the emission spectra of the glass microspere. We report the laser power induce the spectral shift of the whispering-gallery-modes [WGMs] of a glass sphere. The laser power dependence of the WGMs spectral position is about 0.0252nm/mW under 976nm excitation. Maybe, the glass microsphere can be used as a temperature sensor.

Based on the Arrayed Waveguide Grating (AWG) equation and output light intensity equation, dual peaks electro-optical AWG is presented, whose properties are analyzed in details in the paper. The experiments for the electro-optical dual peaks AWG are simulated by Optiwave software, and the experimental results verify the theory very well.

This paper describes a high-performance multiplexed vibration sensor system using fiber lasers. A serial vibration sensor array consists of four short cavity fiber lasers. The system employs a single, polarization-insensitive, unbalanced Michelson interferometer to translate individual laser wavelength shifts induced by vibration signals into interferometer phase shifts. A dense wavelength division demultiplexor (DWDM) with high channel isolation is inserted to demultiplex each laser signal as a wavelength filter. Finally, a digital phase demodulator based on the phase generated carrier technique is used to achieve high-resolution interrogation. Experimental results show that no observable crosstalk is measured on the output channels, and the minimal detectable acceleration of this system is ~200ng/sHz at 250Hz, which is fundamentally limited by the frequency noise of the lasers.