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Online ISSN 1350-911X Print ISSN 0013-5194

Electronics Letters

Volume 26, Issue 3, 1 February 1990

Volumes & issues:

Volume 26, Issue 3

1 February 1990

Potential use of optimal polarisations in sensing the canting angle distribution of raindrops
Noise performance comparison for third and fourth order cascaded sigma–delta modulators having parameter tolerance errors
Deep level transient spectroscopy of n-AlGaAs/GaAs high electron mobility transistors
  • Author(s): J. Goostray ; H. Thomas ; D.V. Morgan ; E. Kohn ; A. Christou ; S. Mottet
  • Source: Electronics Letters, Volume 26, Issue 3, p. 159 –160
  • DOI:  10.1049/el:19900108
  • Type: Article
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  • p. 159 –160 (2)
    Deep level transient spectroscopy has been used to characterise the traps found in MBE grown n-AlGaAs/GaAs HEMTs. In addition to DX centres two further traps common to different HEMT structures are reported. We have identified an electron trap (Ea = 0.6 eV) distributed nonuniformly in the AlGaAs donor layer, and an interface state trap (Ea = 0.55 eV) located close to the two dimensional electron gas.
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Ultra high transconductance 0.25 μm gate MESFET with strained InGaAs buffer layer
Recovery effect in radiowave propagation
  • Author(s): Z. Wu ; T.S.M. Maclean ; N. Jayasundere ; L.J. Carter ; A.G. Williamson
  • Source: Electronics Letters, Volume 26, Issue 3, p. 162 –163
  • DOI:  10.1049/el:19900110
  • Type: Article
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  • p. 162 –163 (2)
    The recovery effect in inhomogeneous propagation, often referred to as sea gain, is analysed by means of the Compensation Theorem. The resulting solution takes the form of an integral equation, but in the particular case when the second medium is a perfect conductor a solution in simple integral form is possible. Numerical results applied to sea water, considered as a perfect conductor in the low MHz range, agree well with those obtained by experiment.
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Analysis of the wavelength dependence of Raman backscatter in optical fibre thermometry
  • Author(s): P.J. Samson
  • Source: Electronics Letters, Volume 26, Issue 3, p. 163 –165
  • DOI:  10.1049/el:19900111
  • Type: Article
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  • p. 163 –165 (3)
    We present an analysis of the Raman backscatter for optical fibre distributed temperature sensors to quantify the effect of varying the pump wavelength. An optimal pump wavelength was found based on maximising the anti-Stokes backscattered power from the endpoint of the fibre. This optimum pump wavelength was found to vary as the fourth root of the distance to the endpoint of the fibre. The sensitivity of the system response to non-optimum pump wavelengths was also analysed. Results are presented for both direct detection and photon counting schemes.
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Phased array beam steering using phase-locked loops
Blue upconversion fluorozirconate fibre laser
Radiometric rain attenuation measurements at 11.6 GHz in Peru
  • Author(s): A.W. Dissanayake ; J.E. Allnutt ; D.K. McCarthy
  • Source: Electronics Letters, Volume 26, Issue 3, p. 168 –170
  • DOI:  10.1049/el:19900114
  • Type: Article
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  • p. 168 –170 (3)
    Rain attenuation is one of the key design parameters when setting up satellite communication systems at frequencies above 10 GHz. Reliable and economical system design requires fairly accurate estimates of this parameter. Although rain attenuation prediction models are available for temperate climates, little has been reported for tropical regions where rain impairments can be very much more severe. This letter presents radiometrically determined rain attenuation results at 11.6 GHz in a tropical climate.
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Application of the method of lines to cylindrical inhomogeneous propagation structures
Room temperature negative differential resistance in the quasi-one-dimensional ballistic resistor
Approximate formulas for step discontinuities in circular waveguides
High sensitivity 5 Gbit/s optical receiver module using Si IC and GaInAs APD
  • Author(s): S. Fujita ; T. Suzaki ; A. Matsuoka ; S. Miyazaki ; T. Torikai ; T. Nakata ; M. Shikada
  • Source: Electronics Letters, Volume 26, Issue 3, p. 175 –176
  • DOI:  10.1049/el:19900118
  • Type: Article
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  • p. 175 –176 (2)
    A 5 Gbit/s optical receiver module was developed by using a wideband transimpedance Si IC and a high gain-bandwidth product GaInAs APD. A 6 GHz bandwidth Si IC utilising a f1 = 20 GHz Si MMIC process, bare chip mounting of a Si IC and an APD to minimise parasitic capacitance, made it possible to realise high speed operation and high receiver sensitivity of −31.8 dBm.
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Polarisation- and pattern-independent optical FSK heterodyne system using data-induced polarisation switching
Analogue MOS current-mode circuits for three-dimensional integrated smart image sensor
Dual-loop slot array antenna radiating circularly polarised wave
  • Author(s): K. Hirose ; H. Horiuchi ; H. Nakano
  • Source: Electronics Letters, Volume 26, Issue 3, p. 179 –180
  • DOI:  10.1049/el:19900121
  • Type: Article
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  • p. 179 –180 (2)
    An array antenna consisting of dual-loop slot elements with a simple feeding system is realised. Each dual-loop element has two loop slots that are simultaneously fed by a single triplate transmission line. A narrowed beam, of circular polarisation, with an axial ratio of less than 3 dB, is obtained over a 3% bandwidth. The measured radiation pattern agrees well with a pattern calculated using array theory.
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Electromagnetic scattering from nonspherical particles: a new polarisability model with application to agglomerating spheres
Improved ICMA/CD protocol in packet mobile radio networks
Electroabsorption by semiconductor microcrystallites in glass: observation of Franz-Keldysh oscillations
Fabrication of long lengths of low excess loss erbium-doped optical fibre
Femtosecond soliton amplification in erbium doped silica fibre
Fabrication of domain reversed gratings for SHG in LiNbO3 by electron beam bombardment
  • Author(s): R.W. Keys ; A. Loni ; R.M. De La Rue ; C.N. Ironside ; J.H. Marsh ; B.J. Luff ; P.D. Townsend
  • Source: Electronics Letters, Volume 26, Issue 3, p. 188 –190
  • DOI:  10.1049/el:19900127
  • Type: Article
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  • p. 188 –190 (3)
    A novel technique for the lithographic definition and the fabrication of domain reversed regions in LiNbO3 is reported, with application to periodic structures for SHG. For the first time, to our knowledge, domain reversal has been achieved on the negative c-face of the crystal. Such a structure should be useful for quasiphasematched second harmonic generation of infra-red laser radiation.
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Submicron-gate ion-implanted In0.15Ga0.85As/GaAs MESFETs with graded indium composition
  • Author(s): G.W. Wang ; M. Feng ; R. Kaliski ; J.B. Kuang
  • Source: Electronics Letters, Volume 26, Issue 3, p. 190 –191
  • DOI:  10.1049/el:19900128
  • Type: Article
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  • p. 190 –191 (2)
    0.25 µm and 0.5 µm gate ion-implanted MESFETs have been fabricated on In0.15Ga0.85As epitaxial layers. These layers are grown by MOCVD on three inch diameter GaAs substrates with the indium mole fraction graded from 15% at the InGaAs/GaAs heterointerface to 0% at the surface. Both devices show excellent DC and microwave performance. From S-parameter measurements, extrinsic current gain cutoff frequencies fts of 120 and 61 GHz are obtained for the 0.25µm and 0.5µm gate MESFETs, respectively. This work investigates the potential of small-bandgap InGaAs materials for submicron-gate MESFET applications.
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Gain limitation of fibre Raman amplifiers considering third Stokes wavelength generation
Epitaxial lift-off GaAs LEDs to Si for fabrication of opto-electronic integrated circuits
  • Author(s): I. Pollentier ; P. Demeester ; A. Ackaert ; L. Buydens ; P. Van Daele ; R. Baets
  • Source: Electronics Letters, Volume 26, Issue 3, p. 193 –194
  • DOI:  10.1049/el:19900130
  • Type: Article
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  • p. 193 –194 (2)
    We report, for the first time, the successful integration of GaAs LEDs on Si using the epitaxial lift-off technique. LEDs were processed after the transfer and could be aligned to features on the Si substrate. LED contacts were defined on both sides of the thin layer. Operation characteristics similar to those of LEDs grown on GaAs were observed. This realisation holds out interesting prospects in the fabrication of quasi-monolithic opto-electronic integrated circuits.
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1.31–1.36µm optical amplification in Nd3+-doped fluorozirconate fibre
Compatible enhancement of terrestrial PAL TV transmission
High microwave performance ion-implanted GaAs MESFETs on InP substrates
  • Author(s): M. Wada  and  K. Kato
  • Source: Electronics Letters, Volume 26, Issue 3, p. 197 –199
  • DOI:  10.1049/el:19900133
  • Type: Article
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  • p. 197 –199 (3)
    Ion implantation was employed, for the first time, in fabricating GaAs MESFETs in undoped 2µm thick GaAs epitaxial layers directly grown on InP substrates by low-pressure MOVPE. The Si-ion-implanted GaAs layer on InP substrates showed excellent electrical characteristics: a mobility of 4300cm2/Vs with a carrier density of 2 × 1017cm−3 at room temperature. The MESFET (0.8 µm gate length) exhibited a current-gain cutoff frequency of 25GHz and a maximum frequency of oscillation of 53GHz, the highest values yet reported for GaAs MESFETs on InP substrates. These results demonstrate the high potential of ionimplanted MESFETs as electronic devices for high-speed InP-based OEICs.
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Verification of waveguide type optical circulator operation
Design of IIR group delay equalisers
Short delay measurement by polarity cross correlation
AlGaAs/GaAs heterojunction bipolar transistors fabricated with various collector-carrier-concentrations
Atmospheric pressure, low temperature (<500°C) UV/ozone oxidation of silicon
Algorithm for prime length discrete cosine transforms
Interdiffusion of InGaAs/InP quantum wells by germanium ion implantation
Transconductance dependence on gate length for GaAs gate pseudomorphic and conventional SISFETs at 300 and 77 K
  • Author(s): P.E. Schmidt ; E. Barbier ; P. Collot ; C. Gaonach ; M. Champagne ; D. Pons
  • Source: Electronics Letters, Volume 26, Issue 3, p. 210 –211
  • DOI:  10.1049/el:19900141
  • Type: Article
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  • p. 210 –211 (2)
    We report on the transconductance dependence on gate length for pseudomorphic (PM) and conventional GaAs gate SISFETs. With an identical material structure, except for the GaInAs channel, PM-SISFETs have higher transconductances at room temperature, for gate lengths between 1 µm and 19 µm. At 77 K, however we show that higher transconductances are obtained with conventional SISFETs having gate lengths larger than 2 µm.
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Short-wavelength (638 nm) room-temperature CW operation of InGaAlP laser diodes with quaternary active layer
  • Author(s): M. Ishikawa ; H. Shiozawa ; Y. Tsuburai ; Y. Uematsu
  • Source: Electronics Letters, Volume 26, Issue 3, p. 211 –213
  • DOI:  10.1049/el:19900142
  • Type: Article
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  • p. 211 –213 (3)
    638 nm room temperature (25°C) CW operation was successfully achieved by InGaAlP visible light laser diodes with a quaternary active layer. A transverse mode stabilised selectively buried ridge-waveguide structure was fabricated by metalorganic chemical vapour deposition. The threshold current was 100 mA at 25°C and CW operation was attained at up to 50°C. The oscillation wavelength was the shortest for room temperature CW operations of laser diodes ever reported.
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Growth of high quality InP with metal organic molecular beam epitaxy
High-power CW operation of broad area InGaAlP visible light laser diodes
30 GHz picosecond pulse generation from actively mode-locked erbium-doped fibre laser
New electro-optic materials using guest-host systems
AGC based on hard detected FFH signal matrices
  • Author(s): I. Vajda
  • Source: Electronics Letters, Volume 26, Issue 3, p. 218 –219
  • DOI:  10.1049/el:19900147
  • Type: Article
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  • p. 218 –219 (2)
    An algorithm for automatic gain control (AGC) is proposed for a frequency hopped multilevel FSK system. The control information is gained only from the hard detected (binary) time-frequency signal matrices. According to this information the AGC algorithm adjusts the detection threshold close to the optimum, which corresponds to the minimum symbol decoding error probability. In the analysis of the algorithm, a multi-user radio channel is assumed.
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Erratum: Optimal property of class of finite-energy signals with application to estimation of duration, power and amplitude of transients

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