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image of Volume 24, Issue 21
Online ISSN 1350-911X Print ISSN 0013-5194

Electronics Letters

Volume 24, Issue 21, 13 October 1988

Volumes & issues:

Volume 24, Issue 21

13 October 1988

Quantum confined Stark effect in GaInAs/InP single quantum wells grown by low pressure MOVPE
  • Author(s): A.J. Moseley ; D.J. Robbins ; A.C. Marshall ; M.Q. Kearley ; J.I. Davies
  • Source: Electronics Letters, Volume 24, Issue 21, p. 1301 –1302
  • DOI:  10.1049/el:19880884
  • Type: Article
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  • p. 1301 –1302 (2)
    We report the first measurements of the quantum confined Stark effect in single GaInAs/InP quantum wells using photocurrent spectra from a single 80 Å well. Well resolved excitonic features are observed for values of electric field up to 3 × 105 V/cm, whose field dependent shift and peak height are in excellent agreement with the predictions of an effective mass calculation, thus demonstrating that there are no intrinsic factors limiting this effect in the GaInAs/InP material system.
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Generalised partitioned-charge-based bipolar transistor modelling methodology
  • Author(s): R.J. McDonald
  • Source: Electronics Letters, Volume 24, Issue 21, p. 1302 –1304
  • DOI:  10.1049/el:19880885
  • Type: Article
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  • p. 1302 –1304 (3)
    A generalised formulation of the partitioned-charge-based (PCB) non-quasi-static (NQS) bipolar junction transistor (BJT) model is developed. The methodology, derived by taking moments of the hole (electron) continuity equation, allows the use of arbitrary weighting functions to partition the excess charge in the quasi-neutral base (QNB) to obtain an optimal NQS BJT model within the PCB equivalent network representation.
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High performance polarisation splitting fibre coupler
Temperature sensor based on a fibre-optic differential delay RF filter
Monte Carlo particle investigation of noise in short n+-n-n+ GaAs diodes
Radiowave propagation over a cliff edge
Optical 4-ary FSK modulation and demodulation experiment
Efficient CMOS counter circuits
  • Author(s): J.-R. Yuan
  • Source: Electronics Letters, Volume 24, Issue 21, p. 1311 –1313
  • DOI:  10.1049/el:19880891
  • Type: Article
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  • p. 1311 –1313 (3)
    Several efficient counters are presented. A nine-transistor divide-by-two circuit is used as a basic building block. With transistor sizing, an input frequency of 400 MHz can be adopted by an asynchronous counter, while an eight-bit synchronous counter can achieve clock rates of more than 200 MHz in a 3μm CMOS process. The power consumption of the proposed precharged dynamic synchronous counter is reduced to almost half as much as normal.
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WDM coherent star network with absolute frequency reference
  • Author(s): Y.C. Chung ; K.J. Pollock ; P.J. Fitzgerald ; B. Glance ; R.W. Tkach ; A.R. Chraplyvy
  • Source: Electronics Letters, Volume 24, Issue 21, p. 1313 –1314
  • DOI:  10.1049/el:19880892
  • Type: Article
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  • p. 1313 –1314 (2)
    A WDM coherent star network with an absolute frequency reference was demonstrated. The absolute reference was obtained from a GaInAsP DFB laser frequency-locked to atomic Ar transition at 1.2960μm. The resonant frequencies of a tunable fibre Fabry-Perot interferometer, locked to this absolute reference, were used to frequency-lock the transmitting lasers. Thus, the transmitting lasers operated at different, but fixed optical frequencies. The receiver sensitivity was not degraded by the addition of the absolute frequency reference to the network.
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New method of obtaining weight distribution of binary convolutional codes
New transverse-domain formation mechanism in a quarter-micrometre-gate HEMT
Analytical model of noise of a switched flip-flop
Characterisation of an optoelectronically pulsed broadband microwave antenna
New canonic variable frequency RC harmonic oscillator with two similar sections
Radiation pattern of square patch mounted diagonally on cylinder
Hydrogen permeation in optical fibres with hermetic carbon coatings
  • Author(s): P.J. Lemaire ; K.S. Kranz ; K.L. Walker ; R.G. Huff ; F.V. Dimarcello
  • Source: Electronics Letters, Volume 24, Issue 21, p. 1323 –1324
  • DOI:  10.1049/el:19880899
  • Type: Article
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  • p. 1323 –1324 (2)
    Hydrogen permeation has been measured for optical fibres with hermetic carbon coatings. Data obtained at elevated temperatures and high hydrogen pressures lead to predictions of extremely low permeation rates at typical operating conditions. In situ loss measurements have shown the existence of a lag time, during which no hydrogen reaches a fibre's interior.
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High-efficiency electroabsorption in quaternary AlGaInAs quantum-well optical modulators
Robot guidance using standard mark
  • Author(s): C.-N. Shyi ; J.-Y. Lee ; C.-H. Chen
  • Source: Electronics Letters, Volume 24, Issue 21, p. 1326 –1327
  • DOI:  10.1049/el:19880901
  • Type: Article
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  • p. 1326 –1327 (2)
    A fast single-view approach to determining the robot location using the standard mark is proposed. In the approach, a standard mark with triangle pattern and location code is used as the reference target. No prerequisite condition is imposed in grabbing the image, and only simple 3-D vector algebra is used in calculating the location. Therefore, the alignment error can be avoided and the speed of location determination can be very fast.
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Super low-noise HEMTs with a T-shaped WSix gate
  • Author(s): I. Hanyu ; S. Asai ; M. Nunokawa ; K. Joshin ; Y. Hirachi ; S. Ohmura ; Y. Aoki ; T. Aigo
  • Source: Electronics Letters, Volume 24, Issue 21, p. 1327 –1328
  • DOI:  10.1049/el:19880902
  • Type: Article
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  • p. 1327 –1328 (2)
    A T-shaped quarter-micron gate structure composed of WSix/Ti/Pt/Au has been developed for low-noise AlGaAs/GaAs HEMTs. The gate resistance Rg was reduced to 0.3 Ω for devices with 200 μm-wide gates despite using WSix, and the source resistance Rs reached 0.28 Ωmm by minimising the source-gate distance using a self-alignment technique. This HEMT exhibited the lowest reported noise figure of 0.54 dB with an associated gain of 12.1 dB at 12 GHz.
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Resonant leaky-wave coupling in linear arrays of antiguides
  • Author(s): D. Botez ; L.J. Mawst ; G. Peterson
  • Source: Electronics Letters, Volume 24, Issue 21, p. 1328 –1330
  • DOI:  10.1049/el:19880903
  • Type: Article
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  • p. 1328 –1330 (3)
    In a uniform array of antiguides, when codirectional leaky waves from adjacent elements add in phase each element equally couples to all others, causing the fundamental-mode near field to become uniform. The resonance condition is derived. When codirectional leaky waves are out of phase, coupling is only nearest-neighbour, causing the fundamentalmode near-field intensity envelope to be cosine-like. The consequences are discussed.
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Correlation detection and trellis decoding of CPFSK signals
High-resolution, current-mode A/D convertors using active current mirrors
Irreducible error rate in aeronautical satellite channels
High-power, mode-locked Nd:fibre laser pumped by an injection-locked diode array
All polarisation maintaining fibre DPSK transmission system experiment
  • Author(s): J.M.P. Delavaux ; R.W. Smith ; L.D. Tzeng ; J.R. Simpson ; A.J. Ritger ; H.B. Yin
  • Source: Electronics Letters, Volume 24, Issue 21, p. 1335 –1336
  • DOI:  10.1049/el:19880908
  • Type: Article
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  • p. 1335 –1336 (2)
    An all polarisation maintaining (PM) fibre heterodyne 1.4Gbit/s DPSK system experiment is demonstrated. Good and stable polarisation extinction ratio (>20dB) is achieved while using low loss keyed connectors between the various optical components. A bit error rate (BER) lower than 10−9 is measured for both short (10m) and long (2.6km) AT&T PM fibres.
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64-channel digital TV distribution system operating at 4.4 Gbit/s
Nonlinear, two-moded, single-fibre, interferometric switch
Strategies for combatting base station failure in highway microcellular clusters
Deep states associated with stacking faults in silicon
Propagation characteristic for a suspended substrate microstrip line with pedestal
Self-aligned bipolar transistor using double thermal oxidation
  • Author(s): P.T. Lai ; A. Kassam ; C.A.T. Salama
  • Source: Electronics Letters, Volume 24, Issue 21, p. 1343 –1345
  • DOI:  10.1049/el:19880914
  • Type: Article
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  • p. 1343 –1345 (3)
    A novel process is proposed to self-align the emitter and extrinsic base in a bipolar transistor. The process involves the use of double thermal oxidation and RIE to create a steep oxide emitter sidewall. The method avoids the potential problems of LPCVD oxide and can remove the residual poly on the extrinsic base, both of which lead to base-emitter shorts. It also eliminates the need for growth of adhesion oxide and annealing of LPCVD oxide. The devices thus fabricated exhibit a high current gain of 130 and high punchthrough voltage of 20V.
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Optimisation considerations for measurement of weak thermal lensing in laser media
Active radiating element using FET source integrated with microstrip patch antenna
Integrated-optic rotating waveplate frequency shifter
Monolithic GaInAs/InP FET inverter amplifiers for long-wavelength OEICs
  • Author(s): P.J.G. Dawe ; W.S. Lee ; G.R. Antell ; D.A.H. Spear ; S.W. Bland
  • Source: Electronics Letters, Volume 24, Issue 21, p. 1349 –1351
  • DOI:  10.1049/el:19880918
  • Type: Article
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  • p. 1349 –1351 (3)
    Monolithically integrated inverter amplifiers based on MOCVD-grown GaInAs/InP heterojunction FETs have been made. 1 μm-gate-length FETs exhibited a typical pinchoff voltage of −1.5V, transconductance of 160mS/mm and DC drain conductance of 2–4mS/mm, at zero gate bias. Amplifier voltage gain as high as 27 was measured at DC, dropping to 11 above 1 MHz due to the presence of an extra frequency-dependent drain conductance component.
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Erratum: Easy programming for fast computation of S-matrix sensitivities
Erratum: Exact calculation of partial-height waveguide Y-junction circulator using mode-matching technique
Erratum: Modes of phase-locked diode-laser arrays of closely spaced antiguides
Erratum: Multibit oversampled Σ-Δ A/D convertor with digital error correction
Erratum: Analytical model for semiconductor laser amplifiers in coherent optical systems
Erratum: Continuous-wave operation of lateral current injection multiquantum-well laser

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