bluuebunny/crossref_metadata_2025_split huggingface dataset:
Analysis of beam divergence in InGaAsP/InP semiconductor laser diodes
Authors: Ghafoori‐Shiraz H. 
Published: July 2007

AbstractThe beam divergence angles for the fundamental TE mode both in the directions parallel and perpendicular to the junction plane of InGaAsP/InP semiconductor laser diodes emitting at 1.3 and 1.55 μm have been investigated. The analysis is based on the effective‐index method and the results can be used to design laser diodes (LDs) with minimum beam divergence which will improve the coupling efficiency between LDs and single‐mode fibers.
Signal and noise in a coherent optical communication system using raman amplifier
Authors: Kao Ming‐Seng , Wu Jingshown 
Published: July 2007

AbstractWe present analytical expressions for the signal and the amplified spontaneous emission (ASE) noise in a coherent optical system using Raman amplification. The results show that the signal spectrum is unaffected by the amplifier and the ASE noise can be thought of as additive white Gaussian noise within the signal bandwidth.
Generation of microwave signals from a laser diode coupled to an external cavity
Authors: Arora Krishna , Arora Rajendra K. 
Published: July 2007

AbstractThis article describes a technique by which a laser diode coupled with an external cavity is used in an interferometric system resulting in a direct envelope modulation of the optical carrier. The laser output is fed to a Mach‐Zehnder interferometer in which the time delay associated with the path imbalance is adjusted to half the time period Tm of the modulating sawtooth current. The two signals are heterodyned to simulate an envelope modulated optical signal.
Binary phase only joint transform correlator
Authors: Yu Francis T. S. , Nagata Toshio 
Published: July 2007

AbstractA joint transform hybrid optical correlator as applied to binary phase only filtering for pattern recognition is proposed. The interference fringes of the joint Fourier transformation, due to the reference and the input targets, are captured by a CCD camera feeding into a microcomputer for binarization. A binarized phase only filter, in principle, can be written onto a spatial light modulator (SLM). By simple coherent illumination of SLM, correlation operation of the reference and the input targets can be obtained. A computer simulation for the target embedded in an additive Gaussian noise is provided.
Lumped element hybrid networks for GaAs MMICs
Authors: Fusco V. F. , O'Caireallain S. B. D. 
Published: July 2007

AbstractThe use of lumped elements in microwave monolithic circuits (MMICs) is an essential feature allowing substantial reduction of GaAs substrate and reduced area cost when compared with conventional distributed microwave designs. The development of low loss passive circuit elements is therefore critical for the realisation of space conservative and efficient monolithic circuits.This paper discusses the properties of a series of lumped element designs that exhibit the same functional behaviour as the distributed quarter‐wavelength quadrature branchline coupler and presents a set of closed equations for their design.
Inelastic multiple scattering by active molecules embedded in randomly distributed spherical scatterers
Authors: Wang Zhi‐Liang , Lin Wei‐Gan 
Published: July 2007

AbstractAccording to the model of equivalent dipoles for active molecules, the analysis of inelastic EM scattering by active molecules embedded in a sphere is given by the method of dyadic Green's functions at first and then, based on the theory of elastic multiple scattering by randomly distributed spherical scatterers which we have developed recently, a new theory for analysis of inelastic multiple scattering by active molecules embedded in randomly distributed spherical scatterers also is developed.
A method of generating a linear frequency sweep in the microwave band
Authors: Hua Li 
Published: July 2007

AbstractThis article describes a method for generating a linear frequency sweep of more than 300 MHz in the band of 0.5 to 2.5 GHz using a phase‐locked loop and a design of microwave voltage‐controlled oscillator using a short‐circuited transmission line and a varactor diode as the tuned circuit. The result of linearity measurements on the system is presented.
First‐order eigenmode analysis of symmetrical five‐port microstrip ring coupler
Authors: Yeo S. P. , Yeo T. S. , Ng K. M. 
Published: July 2007

AbstractExplicit formulas to predict the characteristics of a symmetrical five‐port microstrip ring coupler are obtained from a first‐order eigenmode analysis. Tests on a prototype coupler over the 2—4‐GHz bandwidth indicate that the agreement between theory and experiment is reasonably good.
Low‐impedance matching: The straight stub solution
Authors: Giannini F. , Bartolucci G. , Ruggieri M. 
Published: July 2007

AbstractThe requirement of low impedances in most integrated circuits is solved through the use of straight stubs, treating them as one‐dimensional structures.The inadequacy of that approach can be overcome by adopting a complete modal theory—and the corresponding synthesis tools—developed to characterize those electromagnetic aspects deriving from the “planarity” of the structure.The simulations performed adopting both commercial CAD packages and the modal approach have been compared with some experiments and the need for a better characterization for the presently available cross‐junction element models has been pointed out.
Interferometric waveguide modulator with polarization‐independent operation
Authors: Xue‐Feng Huang , Guo‐Xian Yu , Hai‐Ting Zhang 
Published: July 2007

AbstractA Ti: NiNbO3 polarization‐independent modulator is described, which has two sets of electrodes with approximately equal applied voltages. The drive voltages of TE and TM mode at 0.633 μm are about 15 and 11 V, respectively, with above 95% modulation.
Local reflected millimeter wave power from moving strip illuminated semiconductor panel
Authors: Rahnavard M. H. 
Published: July 2007

AbstractMoving spot illuminated semiconductor panels are used as millimeter wave image converters. To determine the performance of this system, knowledge of the response of illuminated semiconductor panels is required. In this paper local reflected millimeter power from moving strip illuminated semiconductor panels as a function of scanning velocity, width of the strip, time and so forth, is studied.
Scattering of a tem wave from a time varying SLAB
Authors: Elcrat Alan R. , Foster John D. , Walsh John L. 
Published: July 2007

AbstractA finite difference method based on characteristic coordinates is applied to Maxwell's equations for scattering of a TEM wave from an infinite slab. The electric properties of the slab are varied with time, and if the permittivity oscillates with high frequency, a resonant type phenomena is observed.
A novel phase‐noise and polarization fluctuations compensating coherent optical system
Authors: Betti S. , Curti F. , de Marchis G. , Iannone E. 
Published: July 2007

AbstractA novel coherent optical system is proposed that is independent of the received state of polarization and widely insensitive to phase‐noise. It is based on transmission of the phase‐modulated signal and a reference carrier on two orthogonal polarizations and that makes feasible PSK heterodyne systems with phase‐noise affected sources with less than 3 dB penalty.
Scattering by a conformal array of metallic patches
Authors: Ko Wai L. , Mittra Raj 
Published: July 2007

AbstractThe scattering characteristics of metallic patches arranged on a parabolic cylindrical surface are investigated. The induced surface current on each patch is identified as the current induced on the center patch of a planar array, which is tangent to the parabolic cylindrical surface at the patch. Each of these planar‐array problems is solved by the spectral‐Galerkin method. The scattering pattern from the conformal array is obtained by superposition.
Millimeter‐wave in0.17Ga0.83as power mesfets on GaAs(100) substrates
Authors: Shih H. D. , Kim B. , Bradshaw K. , Tserng H. Q. , Wurtele M. , Duncan W. M. , Moore T. M. 
Published: July 2007

AbstractIn0.17Ga0.83As MESFETs were grown on GaAs(100) substrates by molecular beam epitaxy (MBE). The structure comprised an undoped, In0.17Ga0.83As buffer layer grown directly on GaAs and an In0.17Ga0.83As active layer doped to 5 × 10+ 17cm−3. The defect structure was characterized by cathodoluminescence (CL) in a scanning electron microscope. FETs with 0.25‐μm gate length and 50‐μm gate width were fabricated using a standard processing technique. Excellent dc and microwave performance characteristics were obtained. The best device showed a transconductance (gm) of 400 mS / mm and a current‐gain cutoff frequency (fT) of 75 GHz. At 60 GHz, it delivered a power density of 0.50 W / mm with a gain of 4 dB and a power‐added efficiency of 20%, indicating its superior performance over a standard AIGaAs / GaAs HEMT.
Optically excited microwave ring resonators in gallium arsenide
Authors: McGregor Douglas S. , Park Chang Soo , Weichold Mark H. , Taylor Henry F. , Chang Kai 
Published: July 2007

AbstractMicrostrip ring resonators with fundamental frequencies near 3.5 GHz have been fabricated in semi‐insulating GaAs using an electroplating technique for conductor deposition. Test signals were coupled into the resonators by focusing modulated light into a photoconductive microstripline gap. Loaded Q‐factors measured for one of the rings with optical excitation ranged from 54 at the fundamental frequency to 103 at the third harmonic.
Simulation of coupling efficiency between a laser diode and a single‐mode fiber with microlens end
Authors: Ghafoori‐Shiraz H. , Kotsas A. , Maclean T. S. M. 
Published: July 2007

AbstractA microlens fabricated on the end of a single‐mode fiber (SMF) can increase the coupling efficiency to laser diodes (LDs). A simulation of microlens formation and an analysis of the resulting coupling efficiency have been performed. The results are in good agreement with data obtained experimentally.
Performance criteria for resonant tunneling diodes as millimeter‐wave power sources
Authors: Mehdi I. , Haddad G. I. , Mains R. K. 
Published: July 2007

AbstractA figure‐of‐merit expression is derived for resonant tunneling diodes being used as millimeter‐wave sources. It is found that for very high‐frequency applications the most important parameter is the ratio of the peak current to the device capacitance. Results for lattice‐matched and pseudomorphic InP‐based resonant tunneling structures that have a high figure‐of‐merit are presented.
Coherent optical system based on polarization modulation and stokes parameters differential detection tailored for lan application
Authors: Betti S. , Curti F. , de Marchis G. , Lannone E. 
Published: July 2007

AbstractA novel coherent optical receiver, suitable for LAN applications, is proposed. It is based on Stokes parameters detection and is insensitive to the instantaneous polarization state using a new decision criterion. Moreover, it is widely tolerant to laser phase noise and allows efficient utilization of channel bandwidth.
Transition loss in bent single‐mode optical fibers
Authors: Yamauchi Junji , Nakano Hisamatsu 
Published: July 2007

AbstractThe transition loss in bent fibers is numerically investigated using the phase constant and deformed field obtained by a perturbation method. It is demonstrated that the transition loss is reduced by offsetting the fiber axis. Calculation of the first moment of the transverse field distribution gives an optimum offset value.
Local field analysis of bent optical waveguides
Authors: Cheng Yuehua , Lin Weigan 
Published: July 2007

AbstractThe scalar local field equations are derived from the Maxwell's equation in a bent local coordinate system, and the field transformation function for the TM (or the x‐polarized) modes in our recent papers is corrected as well. It is found that no pure geometry birefringence can be produced if the gradient‐index term of local field equations is neglected when the waveguide we considered is weakly guiding.
symbolic logic processor using cascaded liquid crystal televisions (LCTVs)
Authors: Yu Francis T. S. , Jin Yong , Zhang Chenhua 
Published: July 2007

AbstractA shadow casting optical logic array processor using cascaded programmable liquid crystal televisions (LCTVs) is described. We have shown that the 16 basic logic operations can be easily achieved with this technique. A technique of performing two‐level logic function using a modified version of this proposed architectures is also given. We have shown that any two‐level logic function can be performed with this technique. The experimental demonstrations of this optical symbolic logic processor are also provided.
New design of flat gain and wideband field effect structure
Authors: Byl Christophe , Crosnier Yves 
Published: July 2007

AbstractThis paper provides a new possibility of realizing in chip form wideband amplifiers with simple wide gate field effect structures, by taking advantage of especially designed electrode terminations to overcome inherent traveling wave losses. Demonstration of these properties is performed through various realizations and is based on distributed equivalent circuit modelling.
Numerical analysis of a multilayered dielectric waveguide with a periodic surface
Authors: Yasumoto K. , Kubo H. , Itoh Y. 
Published: July 2007

AbstractAn accurate numerical approach to study the wave guidance in multilayered dielectric waveguides having a periodic surface is presented. The complex propagation constants of a four‐layered dielectric waveguide with a sinusoidal surface are calculated and compared with those obtained by other numerical methods.
Grating‐surface‐emitting laser arrays with > 1 cm output apertures
Authors: Evans G. A. , Carlson N. W. , Bour D. , Hammer J. M. , Lurie M. , Butler J. K. , Palfrey S. L. , Amantea R. , Bibby T. F. A. , Farkas R. E. , Gilbert D. B. , Truxal D. A. 
Published: July 2007

AbstractTwo dimensional grating‐surface‐emitting laser arrays produce up to 4 W peak power from a 60 μm × 1.2 cm aperture. These arrays consist of up to 10 × 27 laser elements and are based on either single or multiple quantum well laser structures.
Coded multipulse position modulation in a noisy optical channel
Authors: Atkin G. E. , Fares D. A. , Corrales H. P. 
Published: July 2007

AbstractIn this paper, Reed‐Solomon codes are applied to a multipulse position modulation scheme derived from a combinatorial design. Under high noise background radiation level, threshold detection of this system offers a better performance compared to a RS coded standard PPM system, considering the same information efficiency in nats per photon, and a similar bandwidth expansion factor.
Double‐slot‐fed microstrip antennas for circular polarization operation
Authors: Aksun M. I. , Wang Z. H. , Chuang S. L. , Lo Y. T. 
Published: July 2007

AbstractUsing the cavity model theory, simple design formulas are developed for double‐slot‐fed circularly polarized microstrip antennas. Equivalent magnetic current sources are assumed at the slot positions and then the electric field distribution under the patch is obtained in terms of cavity modes. By applying the circular polarization conditions to the far‐field components of the electric field, the loci of the positions of the slots for the circular polarization operations are found. Experimental results are successfully demonstrated based on the theoretical designs.
A rapidly convergent galerkin‐collocation (GC) method for the analysis of electromagnetic scattering from thin‐wire structures
Authors: McNamara Derek A. , van Rensburg Daniël J. Janse 
Published: July 2007

AbstractResults obtained using a novel technique for computing the electromagnetic scattering from conducting thin‐wire structures and which exhibit Galerkin‐like convergence properties with collocation‐like computational efficiency, are presented.
Q‐factors and designs of CP microstrip antennas
Authors: Choi S. J. , Lo Y. T. , Chew W. C. 
Published: July 2007

AbstractThis paper discusses simple designs for circularly polarized antennas without the need of phase shifters and power dividing networks. In particular, design formulas of several commonly used microstrip antennas are derived and quantitative information on the antenna Q‐factor is presented to facilitate the design. Design examples are given to illustrate the proposed design procedure.
Absorbing boundary conditions for the finite element solution of the vector wave equation
Authors: Webb J. P. , Kanellopoulos V. N. 
Published: July 2007

AbstractTime‐harmonic electromagnetic field problems in unbounded space may be solved by the finite element method applied inside a sphere which contains the region of interest, providing a suitable boundary condition is imposed on the surface of the sphere. The boundary condition must have the effect of absorbing out‐going waves. A new second‐order absorbing boundary condition (ABC) is proposed, similar to that introduced by Peterson [1], but capable of being incorporated in a variational principle and consequently leading to symmetric finite‐element matrices.
Optically controlled subsystems at HF and at MM‐wavelengths
Authors: Rosen A. , Stabile P. , Janton W. , Gombar A. , Delmaster J. , Basile P. , Hurwitz R. 
Published: July 2007

AbstractThis paper describes the use of optically controlled devices at HF (2‐30) (MHz) in a narrow band antenna coupler using high voltage PIN diodes as switching devices and at 60 GHz as an attenuator / switch. PIN devices tested in an rf circuit between 2.5 and 30 MHz yielded isolation between 28 and 49 dB in the off state and insertion losses as low as 0.1 dB when illuminated with 180 W of optical power. Measurements made at 60 GHz have shown a 0.9 dB insertion loss in the on state and an isolation value of better than 21 dB in the off state.
Characteristic modes for bodies endowed with mutually orthogonal symmetry planes
Authors: Vescovo Roberto 
Published: July 2007

AbstractWe deal with the characteristic modes of perfectly conducting bodies and of loss‐free dielectric or magnetic bodies, endowed with h mutually orthogonal symmetry planes (1 ≥ h ≥ 3). It is shown that by suitably choosing basis and weighting functions, the moment method transforms the eigenvalue equation defining the modes into a matrix eigenvalue equation involving matrices partitioned into 2h diagonal blocks.
A square multiflare horn with 1‐megawatt CW power‐handling capability
Authors: Hoppe Dan 
Published: July 2007

AbstractThe analysis and low‐power testing of a square miltiflare horn designed‐for 1‐megawatt CW operation is described. Design considerations for the five‐port input section are discussed. The required aperture modes are determined from radiation pattern considerations, and analysis of the multiflare section is carried out using mode matching. Measurements demonstrate that a circularly symmetric beam is produced with relatively low sidelobes.
Dual gate mesfet for flat microwave response of directly modulated laser diode
Authors: Rocco M. T. M. , de Salles A. A. 
Published: July 2007

AbstractA dual gate GaAs MESFET (DG‐FET) driver is designed to obtain a flat frequency response from a direct intensity modulated semiconductor laser diode. The DG‐FET input and output matching circuits are designed to compensate the laser diode intrinsic frequency response in a band from 0.3 to 2.0 GHz. A frequency response flatness improvement of more than 15 dB is obtained.
Incremental frequency rules for arbitrary resonant cavities
Authors: Kajfez Darko , Wu Wen Liang , Chu Qingxin 
Published: July 2007

AbstractThe Q factor due to resistive losses in conductor walls of resonant cavities can be evaluated by computing the changes in resonant frequency resulting from small perturbations of either magnetic or dielectric material along the cavity wall. Two rules are presented: one in terms of derivatives, suitable for analytic solutions, and the other in terms of incremental changes, suitable for use with computer codes.
Antenna mode and structural mode RCS: DIPOLE
Authors: Hansen R. C. 
Published: July 2007

AbstractThe short‐circuit, match, and antenna components of RCS are examined for a thin‐wire dipole over a range of lengths and incidence angles. Resonances are identified and discussed in terms of current distributions and antenna patterns. The antenna component contains more resonant peaks than the short‐circuit component due to differences in current distribution. The results are useful for RCS understanding and control.
Frequency chirping in semiconductor‐optical fiber ring laser
Authors: Jiangping Zhang , Peida Ye 
Published: July 2007

AbstractIn this letter, a complete small‐signal analysis for frequency chirping in the semiconductor‐optical fiber ring laser is presented. It shows that chirp‐to‐power ratio (CPR) strongly depends on the junction phase shift, the optical coupling, and the phase detuning between two cavities, especially if the modulation frequency is below the gigahertz range.
Microwave noise performance and frequency response of PIN GalnAs photodiodes
Authors: Gouy J. P. , Vilcot J. P. , Decoster D. , Riglet P. , Patillon J. N. , Martin G. 
Published: July 2007

AbstractWe have measured the noise performance of GaInAs PIN photodiodes in the microwave frequency range. We show that the frequency response of the photodetectors can be deduced from their photocurrent shot noise spectra. The noise level has been measured using a setup which is based on heterodyne microwave mixing.
A broadband microwave linear phase modulator made of high Tc superconductors
Authors: Martens J. S. , Beyer J. B. , Nordman J. E. , Ginley D. S. 
Published: July 2007

AbstractA superconducting linear phase modulator using a single film device made of Tl‐Ca‐Ba‐Cu‐O for operation at 77 K is presented. The modulator has been analyzed from 300 MHz to about 6 GHz with good linearity for peak phase deviations up to 100 rad. Modulation has been observed for carriers up to 35 GHz.
Photoavalanche effects in a GaAs MESFET
Authors: Madjar Asher , Herczfeld Peter R. , Paollela Arthur 
Published: July 2007

AbstractThis paper describes a photomultiplication effect in microwave MESFETs that occurs when the device is operated close to the avalanche breakdown voltage of the drain‐gate Schottky barrier. The multiplication enhances the optical response of the device, which is important when the MESFET is used in a photodetection mode. However, caution is required when the device is operated at high Vds levels so that premature avalanche breakdown is avoided.
Polarization correction of luneburg lens with chiral medium
Authors: Viitanen Ari J. , Lindell Ismo V. , Sihvola An H. 
Published: July 2007

AbstractThe geometrical optics method for the wave propagation in inhomogeneous chiral media, introduced recently, is here applied to the Luneburg lens antenna. For sufficiently small values of the chirality parameter, the geometrical optics rays can be calculated as for the achiral medium and the main effect of the chirality is rotation of polarization along the ray. This effect can be exploited to correct the polarization in the aperture of a lens antenna. In this paper the cross polarization of the Luneburg lens is eliminated through use of an inhomogeneous chirality distribution.
Organic‐on‐inorganic guided wave modulator
Authors: Ryley J. F. , Herczfeld P. , Brophy T. J. 
Published: July 2007

AbstractA high speed, integrated optical intensity modulator based on the application of an organic electrooptic active cladding to an otherwise inactive waveguide is proposed. Computer generated data supporting the proposed device configuration and material selections are presented. The future potential of such devices is discussed.
Cutoff attenuator for azimuthally symmetric transverse electric mode in a cylindrical waveguide
Authors: Elaoud Moncef , Seshadri S. R. 
Published: July 2007

AbstractA theory of the cutoff attenuator for the azimuthally symmetric lowest order transverse electric mode in a cylindrical waveguide is developed. Illustrative numerical results of the insertion loss as well as the frequency response of the attenuator are presented.