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Online ISSN 1350-911X Print ISSN 0013-5194

Electronics Letters

Volume 18, Issue 16, 5 August 1982

Volumes & issues:

Volume 18, Issue 16

5 August 1982

Reflection of spherical waves at plane interfaces where relative index of refraction is near unity
High-quantum-efficiency low-threshold microcleaved AlxGa1−xAs lasers
Buffering strategy for variable-symbol-rate speech waveform coders
Reply: Fundamental mode spot-size measurement in single-mode optical fibres
Fast annealing of 4 in. arsenic-implanted silicon wafers using an imaging furnace
  • Author(s): M. Haond ; D.-P. Vu ; C. Adès
  • Source: Electronics Letters, Volume 18, Issue 16, p. 694 –695
  • DOI:  10.1049/el:19820472
  • Type: Article
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  • p. 694 –695 (2)
    An imaging furnace equipped with a 6.5 kW Xe arc lamp has been used to anneal 4 in. arsenic-implanted silicon wafers in a single exposure. Electrical and structural investigations have shown complete activation without appreciable diffusion of the impurities, and the regrown layers are defect free for low implant dose (5×1014/cm2, 100 keV); for high implant dose (1015/cm2, 200 keV), however, dislocation loops are observed.
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Tunable fibre Raman oscillator in the 1.32–1.41 μm spectral region using a low-loss, low OH− single-mode fibre
Low-loss splicing of a 62.4 km single-mode-fibre link
  • Author(s): J.S. Leach ; G.J. Cannell ; A.J. Robertson ; P. Gurton
  • Source: Electronics Letters, Volume 18, Issue 16, p. 697 –698
  • DOI:  10.1049/el:19820474
  • Type: Article
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  • p. 697 –698 (2)
    A 62.4 km single-mode-fibre link containing 35 splices has been made in the laboratory using equipment and techniques suitable for landline installations. Mean splice attenuations of 0.1 dB at 1.3 μm and 0.08 dB at 1.55 μm were measured. The mean attenuation of the complete spliced link was 0.5 dB/km at 1.3 μm and 0.34 dB/km at 1.55 μm. In addition, the attenuations of 200 splices measured at 1.3 μm are reported.
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Multiplier/detector for SAW spectrum analysers
  • Author(s): P.J. Hall
  • Source: Electronics Letters, Volume 18, Issue 16, p. 699 –700
  • DOI:  10.1049/el:19820475
  • Type: Article
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  • p. 699 –700 (2)
    Surface-acoustic-wave (SAW) spectrum analysers such as compressive receivers can be used to perform real-time, wideband, transform-domain correlation. A major practical difficulty in such systems is the design of a bilinear analogue multiplier with wide input and output bandwidths and good dynamic range. A simple circuit is presented for such a multiplier, and the circuit performance as a square-law detector and correlator is illustrated.
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Thermodisplacement imaging of current in thin-film circuits
  • Author(s): H.K. Wickramasinghe ; Y. Martin ; S. Ball ; E.A. Ash
  • Source: Electronics Letters, Volume 18, Issue 16, p. 700 –701
  • DOI:  10.1049/el:19820476
  • Type: Article
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  • p. 700 –701 (2)
    We present initial results on a novel scheme for measuring current distribution in thin-film circuits. When an AC current passes through a thin-film circuit, the resulting periodic heating sets up a dynamic surface displacement which can be detected using a phase-sensitive laser probe. Results indicate that the present system has a sensitivity of 4 × 10−3 Å for displacement and 2.7 × 10−2°C for temperature in a 1 Hz bandwidth. The spatial resolution can be as small as an optical wavelength and is currently limited to 2 μm by the optics used. As the surface displacement amplitude depends on the thermal properties of the substrate material, the technique can also be used to detect defects beneath the metallisation in integrated-circuit structures.
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Schottky barrier restricted GaAlAs laser
  • Author(s): H. Temkin ; A.K. Chin ; B.V. Dutt
  • Source: Electronics Letters, Volume 18, Issue 16, p. 701 –703
  • DOI:  10.1049/el:19820477
  • Type: Article
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  • p. 701 –703 (3)
    A new type of a simple gain-guided GaAlAs laser using a Schottky barrier restriction (SBR) technique is presented. Low current thresholds of ∼2.2 kA/cm2, CW operation up to 70°C with a T0 = 160°, and a high coupling efficiency to multimode fibres are comparable to the high-quality lasers prepared with more traditional current restriction methods. This excellent performance has been achieved with extremely simple processing afforded by the SBR scheme. Although these SBR lasers have not yet been subjected to aging tests, GaAIAs LEDs fabricated in an identical fashion show excellent reliability.
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Shunt current and excess temperature sensitivity of Ith and ηex in 1.3 μm InGaAsP DH lasers
Autocorrelation function parameters used to indicate incipient blockage in a pneumatic transport system
Short cycling in the Kravitz-Reed public key encryption system
  • Author(s): J. Gait
  • Source: Electronics Letters, Volume 18, Issue 16, p. 706 –707
  • DOI:  10.1049/el:19820480
  • Type: Article
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  • p. 706 –707 (2)
    The Kravitz-Reed public key encryption system, a variant of the MIT system based on Galois fields, is interesting because it offers the potential of high security with efficient implementation. In the letter we demonstrate that high security and efficient implementation are not, in reality, compatible goals with this algorithm. Efficient implementation is subject to a short cycling attack that exposes the secret key to computation. If the parameters of the algorithm are selected for high security, then the algorithm cannot be efficiently implemented.
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Measurement of stresses in elliptical optical fibre or preform
Modified chernoff bound for binary optical communication
Low-temperature (~77 K) properties of InP MOSFETs using anodic-oxide gate insulator
Novel core alignment method for low-loss splicing of single-mode fibres utilising uv-excited fluorescence of Ge-doped silica core
High-speed coating of optical fibres with thermally curable silicone resin using a pressurised die
Hydrogen passivation of deep donor centres in high-purity epitaxial GaAs
Minimum-dispersion spectra of single-mode fibres measured with subpicosecond resolution by white-light crosscorrelation
Theory for self-sustained pulsations in semiconductor lasers

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