Your browser does not support JavaScript!
http://iet.metastore.ingenta.com
1887
banner image
image of Volume 25, Issue 18
Online ISSN 1350-911X Print ISSN 0013-5194

Electronics Letters

Volume 25, Issue 18, 31 August 1989

Volumes & issues:

Volume 25, Issue 18

31 August 1989

Triple layer refractive index profile for tapered fibre beam expanders
All-fibre frequency shifter using piezoceramic SAW device
AuGe/Au ohmic contacts to n-type InP by hot-plate alloying
  • Author(s): S.C. Binari  and  J.B. Boos
  • Source: Electronics Letters, Volume 25, Issue 18, p. 1207 –1209
  • DOI:  10.1049/el:19890810
  • Type: Article
  • + Show details - Hide details
  • p. 1207 –1209 (3)
    We report on the fabrication and characteristics of AuGe/Au ohmic contacts to ion-implanted n-type InP. The contacts have smooth surface morphology, excellent adhesion and good contact resistance uniformity. For samples with carrier concentrations of 1.7×1017 and 1.6×1015cm−3, contact resistances of 0.07 and 0.03 Ωmm, respectively, have been obtained. These values are among the lowest contact resistances reported for n-type InP.
    Add to favourites
    Export citations
Leaky-wave multiple dichroic beam formers
AlGaAs/GaAs emitter-down HBT fabricated by MBE overgrowth
  • Author(s): D.L. Plumton ; H.D. Shih ; F.J. Morris
  • Source: Electronics Letters, Volume 25, Issue 18, p. 1211 –1212
  • DOI:  10.1049/el:19890812
  • Type: Article
  • + Show details - Hide details
  • p. 1211 –1212 (2)
    A planar emitter-down AlGaAs/GaAs heterojunction bipolar transistor, has been fabricated by a molecular beam epitaxy overgrowth of the n-GaAs collector on top of the base layer after the base layer was formed by beryllium implantation and rapid thermal annealing. The emitter down transistors fabricated by this process had DC current gains of 20 , and ring oscillators gave a maximum switching speed of 250ps/gate.
    Add to favourites
    Export citations
Improvement of optical nonlinear response in GaAs/AlGaAs nipi-MQW structure with Au ohmic contact
  • Author(s): H. Ando ; H. Oohashi ; H. Iwamura ; H. Kanbe
  • Source: Electronics Letters, Volume 25, Issue 18, p. 1212 –1214
  • DOI:  10.1049/el:19890813
  • Type: Article
  • + Show details - Hide details
  • p. 1212 –1214 (3)
    Experiments demonstrate that the optical nonlinear response in a GaAs/AlGaAs nipi-MQW structure can be improved by introducing ohmic contacts, which electrically connect n and p-layers. The response time is reduced by more than two orders of magnitude because of the enhanced recombination rate of photoexcited carriers, whereas the figure of merit for absorptive nonlinearity δeh is kept constant and is an order of magnitude larger than that in a conventional GaAs/AlGaAs MQW structure.
    Add to favourites
    Export citations
Fusion splicing of heavy metal fluoride glass optical fibres
Analogue implementation of Hough transform
  • Author(s): D. Ben-Tzvi  and  M. Sandler
  • Source: Electronics Letters, Volume 25, Issue 18, p. 1216 –1217
  • DOI:  10.1049/el:19890815
  • Type: Article
  • + Show details - Hide details
  • p. 1216 –1217 (2)
    In digital implementations of the Hough transform either digital multiplication or table look-up are used in calculations. Equivalent results may be obtained using an analogue representation. Each edge point in the image is used to generate a signal representing the continuous form of the Hough transform for that point. The signal is sampled at regular intervals to provide a discrete sequence of values. It has been shown that such an analogue implementation achieves a significantly better throughput than an equivalent digital implementation. The designed circuit may be integrated as a one-chip hybrid integrated circuit.
    Add to favourites
    Export citations
Dual-loop slot antenna with simple feed
Continuum-miniband superlattice-base transistor with graded-gap electron injector
Thermal CVD of homoepitaxial diamond using CF4 and F2
  • Author(s): R.A. Rudder ; J.B. Posthill ; R.J. Markunas
  • Source: Electronics Letters, Volume 25, Issue 18, p. 1220 –1221
  • DOI:  10.1049/el:19890818
  • Type: Article
  • + Show details - Hide details
  • p. 1220 –1221 (2)
    For the first time, diamond has been grown using low-pressure thermal CVD. No additional excitation such as plasmas or filaments was used. The letter reports the homoepitaxial growth of diamond on type II-A diamond(100) via pyrolysis in a CF4/F2 gas mixture. The fluorine in the process is analogous to the atomic hydrogen in traditional plasma or filament assisted CVD processes in that it serves as an etchant to remove the nondiamond components from the depositing carbon film.
    Add to favourites
    Export citations
Te-to-tm mode conversion in GaAs/AlGaAs superlattice waveguide
  • Author(s): T. Wolf ; C.L. Shieh ; R. Engelmann ; K. Alavi ; J. Mantz
  • Source: Electronics Letters, Volume 25, Issue 18, p. 1221 –1223
  • DOI:  10.1049/el:19890819
  • Type: Article
  • + Show details - Hide details
  • p. 1221 –1223 (3)
    Intrinsic phase matching between a TE and a TM mode is obtained in a GaAs/AlGaAs superlattice waveguide, fabricated by Zn diffusion induced disordering, as a result of the birefringent waveguiding properties of the superlattice in combination with a proper choice of the waveguide geometry. As a consequence, up to 90% polarisation conversion is demonstrated without the application of phase matching techniques.
    Add to favourites
    Export citations
Decoding Reed-Solomon codes generated by any generator polynomial
Modelling interconnect yield in reconfigurable circuits
Critical thickness in strained-layer GaInAs/GaAs quantum well lasers
Narrowband planar microwave active filter
Transmission line analysis of aperture-coupled microstrip antenna
  • Author(s): M. Himdi ; J.P. Daniel ; C. Terret
  • Source: Electronics Letters, Volume 25, Issue 18, p. 1229 –1230
  • DOI:  10.1049/el:19890824
  • Type: Article
  • + Show details - Hide details
  • p. 1229 –1230 (2)
    The letter presents an original analysis of a slot-coupled microstrip antenna. The transmission line model uses previous expressions of conductance and susceptance due to the fringing fields near the edges of the patch; moreover, a simple interpretation of the different impedance transformations is given. Resullts based on the transmission line model are compared with other theoretical analyses (cavity model, moment method) and measurements.
    Add to favourites
    Export citations
Scattering loss from rough sidewalls in semiconductor rib waveguides
Broadband stacked dielectric resonator antennas
Dependence of transconductance on substrate bias in ultrathin silicon-on-insulator MOS transistors
Stabilisation of optically excited self-oscillation
  • Author(s): L.M. Zhang ; D. Uttamchandani ; B. Culshaw
  • Source: Electronics Letters, Volume 25, Issue 18, p. 1235 –1236
  • DOI:  10.1049/el:19890828
  • Type: Article
  • + Show details - Hide details
  • p. 1235 –1236 (2)
    A new experiment demonstrating the stabilisation of an optically driven self-oscillator is reported. The oscillation of the micromechanical silicon resonator is maintained by optical feedback provided by a Fabry-Perot interferometer formed between a semireflecting mirror and the surface of the silicon micromechanical resonator. The stabilisation of the oscillation is achieved by adjusting the frequency of the laser diode powering the system.
    Add to favourites
    Export citations
Coherent detection of stimulated Brillouin backscatter on photoconductive three-wave mixer for sensing applications
  • Author(s): J.K.A. Everard  and  R. Thomas
  • Source: Electronics Letters, Volume 25, Issue 18, p. 1236 –1237
  • DOI:  10.1049/el:19890829
  • Type: Article
  • + Show details - Hide details
  • p. 1236 –1237 (2)
    We describe the coherent detection of stimulated Brillouin scattering (SBS) from an optical fibre, using an InP photoconductive three-wave mixer. In this mixer two optical signals offset by 33 GHz are multiplied together with a microwave signal, all within the same device, to produce an output signal of a few hundred MHz. This arrangement could be used to measure the temperature distribution along a fibre.
    Add to favourites
    Export citations
Dynamic modelling of nonlinear microwave devices
High-power (1 W, CW) single-lobe operation of LPE-grown GaInAsP/GaInP (x = 0.8 μm) separate-confinement single-quantum-well broad-area lasers
  • Author(s): D.Z. Garbuzov ; A.V. Kochergin ; E.U. Rafailov ; N.A. Strugov ; P. Gavrilovic
  • Source: Electronics Letters, Volume 25, Issue 18, p. 1239 –1240
  • DOI:  10.1049/el:19890831
  • Type: Article
  • + Show details - Hide details
  • p. 1239 –1240 (2)
    Liquid-phase epitaxy was used to grow single-quantum-well separate-confinement laser structures with a GaInAsP active layer. Broad-area devices with 100μm-wide stripes that were fabricated from these structures emit over 1 W of optical power per facet at a wavelength of 0.8 μm in continuous room-temperature operation. A stable single-lobed far-field pattern with a beam divergence as low as 0.6° is obtained in pulsed operation.
    Add to favourites
    Export citations
1.5μm band travelling-wave semiconductor optical amplifiers with window facet structure
6–34 GHz offset phase-locking of Nd:YAG 1319 nm nonplanar ring lasers
Characteristic temperature of GaInP/AlGaInP single quantum well lasers
High-speed AlGaAs/GaAs multiple quantum well ridge waveguide lasers
Generation of 2 THz repetition rate pulse trains through induced modulational instability
Design of core support mechanism for mm-wave dielectrically loaded horn
Multistage self-excited linear predictive speech coder
  • Author(s): J.I. Lee  and  C.K. Un
  • Source: Electronics Letters, Volume 25, Issue 18, p. 1249 –1251
  • DOI:  10.1049/el:19890838
  • Type: Article
  • + Show details - Hide details
  • p. 1249 –1251 (3)
    We present an approach to low-rate speech coding based on multistage self-excited linear prediction (SELP). The coder has much lower complexity than a code-excited linear prediction (CELP) coder, but yields comparable output speech quality at the same transmission rate. In the proposed multistage SELP coder, the long-term predictor is modified to model better the onset of a voiced section of speech or voice with high pitch.
    Add to favourites
    Export citations
Accurate current conveyor integrated circuit
Quasi-TEM spectral domain analysis of thick microstrip for microwave and digital integrated circuits
  • Author(s): V.K. Tripathi ; R.T. Kollipara ; L.A. Hayden
  • Source: Electronics Letters, Volume 25, Issue 18, p. 1253 –1254
  • DOI:  10.1049/el:19890840
  • Type: Article
  • + Show details - Hide details
  • p. 1253 –1254 (2)
    A procedure to compute the effective dielectric constants and characteristic impedances of thick microstrip is formulated utilising the computationally efficient quasi-TEM spectral domain method. The results calculated for the impedance and effective dielectric constant are shown to agree well with those obtained by the integral equation and finite element methods. The decrease in the effective dielectric constant of a microstrip as a function of strip thickness is also shown to agree well with the measured data.
    Add to favourites
    Export citations
Fresnel equation studies of longitudinally varying semiconductor rib waveguides: reference wavevector dependence
  • Author(s): D. Yevick ; C. Rolland ; B. Hermansson
  • Source: Electronics Letters, Volume 25, Issue 18, p. 1254 –1256
  • DOI:  10.1049/el:19890841
  • Type: Article
  • + Show details - Hide details
  • p. 1254 –1256 (3)
    We demonstrate that the accuracy of paraxial loss calculations for longitudinally varying semiconductor rib waveguides is significantly affected by the value assumed for the reference refractive index, n0. We then perform a full threedimensional simulation of a weakly guiding single-mode rib waveguide Y-junction, and compare our results to those of the effective index method, obtaining excellent agreement when n0 nearly coincides with the refractive index of the guided mode.
    Add to favourites
    Export citations
Analysis of strongly guiding rib waveguide S-bends: theory and experiment
Epitaxial growth on InP substrates etched with methane reactive ion etching technique
  • Author(s): L. Henry ; C. Vaudry ; A. le Corre ; D. Lecrosnier ; P. Alnot ; J. Olivier
  • Source: Electronics Letters, Volume 25, Issue 18, p. 1257 –1259
  • DOI:  10.1049/el:19890843
  • Type: Article
  • + Show details - Hide details
  • p. 1257 –1259 (3)
    InP substrates have been etched by RIE using a mixture of methane, argon and hydrogen. With angle-resolved photoelectron spectroscopy, we show that, after etching, a nonstoichiometric layer is created at the surface: this layer is phosphorus depleted and extends to a thickness varying from 10 to 40 Å according to the RIE conditions. We demonstrate that a heat treatment under P2 atoms is able to restore the surface crystallinity and permits the growth of high-quality epilayers.
    Add to favourites
    Export citations
Novel approach to reduce number of op-amps in switched-capacitor filters
8×8 element hybridised PLZT/silicon spatial light modulator array
Algorithm for squaring in GF(2m) in standard basis

Most viewed content for this Journal

Article
content/journals/el
Journal
5
Loading

Most cited content for this Journal

Print this page
This is a required field
Please enter a valid email address