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Online ISSN 1350-911X Print ISSN 0013-5194

Electronics Letters

Volume 21, Issue 8, 11 April 1985

Volumes & issues:

Volume 21, Issue 8

11 April 1985

Modulation of near-millimetre-wavelength radiation by magnetic fluids
  • Author(s): J.R. Birch ; C.A. Bentley ; J.P. Llewellyn
  • Source: Electronics Letters, Volume 21, Issue 8, p. 313 –314
  • DOI:  10.1049/el:19850221
  • Type: Article
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  • p. 313 –314 (2)
    The results of some measurements on amplitude modulation of 94, 100 and 110 GHz radiation by a magneto-optical effect in a number of magnetic fluids are described. Modulation at frequencies up to 0.25 MHz has been observed, but this may not represent the intrinsic high-frequency cutoff of the effect. The effects of altering both the composition and the concentration of the magnetic fluid are described.
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Guided-wave optical wavelength-division multi/demultiplexer using high-silica channel waveguides
  • Author(s): M. Kawachi ; Y. Yamada ; M. Yasu ; M. Kobayashi
  • Source: Electronics Letters, Volume 21, Issue 8, p. 314 –315
  • DOI:  10.1049/el:19850222
  • Type: Article
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  • p. 314 –315 (2)
    A guided-wave optical waveguide-division multi/demultiplexer for bidirectional transmission at (0.81 μm, 1.2 μm)/(0.89 μm, 1.3 μm) wavelengths has been realised using high-silica channel waveguides on silicon substrate. The multi/demultiplexer connected with graded-index multi-mode fibres shows a loss of 3.5−5 dB together with far-end and near-end crosstalk levels less than −30 dB and −50 dB, respectively.
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Optically activated vibrations in a micromachined silica structure
  • Author(s): S. Venkatesh  and  B. Culshaw
  • Source: Electronics Letters, Volume 21, Issue 8, p. 315 –317
  • DOI:  10.1049/el:19850223
  • Type: Article
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  • p. 315 –317 (3)
    A microminiature bridge of silicon dioxide, fabricated using anisotropic etch techniques on a silicon substrate, has been set into mechanical vibration by direct interaction with a low-power laser beam. The displacement sensitivity and frequency response of the optomechanical interaction have been characterised using optical interferometry. The implications of the results for the development of radically new optical sensors are discussed.
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Shear transverse waves on corrugated surface of rotated Y-cut quartz
CFAR problems in weibull clutter
400 Mbit/s transmission experiment using two monolithic optoelectronic chips
Low-threshold operation of 1.54 μm InGaAsP/InP DFB laser with second-order grating
Two-parameter characterisation of single-cladded, dispersion-shifted single-mode fibres
High-performance index-guided phase-locked semiconductor laser arrays
  • Author(s): Y. Twu ; K.-L. Chen ; A. Dienes ; S. Wang ; J.R. Whinnery
  • Source: Electronics Letters, Volume 21, Issue 8, p. 324 –325
  • DOI:  10.1049/el:19850229
  • Type: Article
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  • p. 324 –325 (2)
    Using strongly coupled index-guided ridge-waveguide structures and tailoring the gain distribution to the fundamental eigenmode intensity distribution in a five-element coupled laser array, we greatly improve the performance over previously reported results. A stable single-lobe far-field pattern has been observed up to nearly three times threshold. This result is achieved by nonuniform pumping, which tends to excite the fundamental array eigenmode only by preventing spatial hole burning, which causes the excitation of higher-order modes.
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1.3 μm InGaAsP index-guided multirib waveguide laser array
  • Author(s): N.K. Dutta ; T. Cella ; S.G. Napholtz ; D.C. Craft
  • Source: Electronics Letters, Volume 21, Issue 8, p. 326 –327
  • DOI:  10.1049/el:19850230
  • Type: Article
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  • p. 326 –327 (2)
    Phase-locked InGaAsP index-guided multirib waveguide laser arrays emitting at 1.3 μm have been fabricated. These devices have threshold currents in the range 400–500 mA at 30°C and have been operated to pulsed output powers as high as 400 mW. More than 100 mW of output power has been obtained up to an ambient temperature of 60°C. The lasers emit in multilongitudinal modes with a far-field divergence of 20° × 40°.
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Lateral epitaxial overgrowth of silicon over recessed oxide
  • Author(s): T.S. Jayadev ; E. Okazaki ; H. Petersen ; M. Millman
  • Source: Electronics Letters, Volume 21, Issue 8, p. 327 –328
  • DOI:  10.1049/el:19850231
  • Type: Article
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  • p. 327 –328 (2)
    There has been considerable interest in silicon-on-insulator (SOI) technology recently because of its potential applications in VLSI. CMOS circuits in SOI have higher speed because of the absence of substrate capacitance, and freedom from latch-up because of dielectric isolation. Recently, memory circuits like DRAMs have reached the physical limits of what is possible in two dimensions, and hence there is a growing need for 3-dimensional circuits. SOI offers a possible avenue to realise such 3-D circuits and thus lead the way to the next generation of memories and integrated circuits.
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Double heterojunction GaAs/GaAlAs I2L inverter
  • Author(s): P. Narozny  and  H. Beneking
  • Source: Electronics Letters, Volume 21, Issue 8, p. 328 –329
  • DOI:  10.1049/el:19850232
  • Type: Article
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  • p. 328 –329 (2)
    GaAs/GaAlAs double heterojunction I2L inverters with a vertical pnp current source were fabricated by ion implantation and Zn-diffusion into LPE structures. The current gain of the upside-down-operated double heterojunction npn transistor has been improved by a factor of two compared to the gain of the npn transistor of the otherwise similar structure. In addition, the wide-gap junction pnp transistor gives a solution to the critical switch-on problem which can occur when a wide-gap emitter transistor is used for the switching transistor.
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Double heterostructure and multiquantum-well lasers at 1.5–1.7 μm grown by atmospheric pressure MOVPE
  • Author(s): A.W. Nelson ; R.H. Moss ; J.C. Regnault ; P.C. Spurdens ; S. Wong
  • Source: Electronics Letters, Volume 21, Issue 8, p. 329 –331
  • DOI:  10.1049/el:19850233
  • Type: Article
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  • p. 329 –331 (3)
    The first successful growth and fabrication of GaInAs/InP MQW and CW GaInAsP DH lasers by atmospheric pressure MOVPE is reported. Room-temperature CW operation of DH lasers was obtained by using the ridge-waveguide laser design, and threshold currents as low as 53 mA were measured. MQW lasers, which also operated at room temperature, were fabricated, and emission spectra obtained from these devices showed a clear spectral narrowing compared with the DH lasers together with a wavelength shift, in good agreement with theoretical predictions.
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Quasistatic analysis of a dynamic sense amplifier
Rigorous and approximate calculations of antireflection layer parameters for travelling-wave diode laser amplifiers
Spatial resolution of coherent ALOHA collision sources
Testability enhancement of domino CMOS logic
Improved high-power twin-channel laser with blocking layer
  • Author(s): C.B. Morrison ; L.M. Zinkiewicz ; A. Burghard ; L. Figueroa
  • Source: Electronics Letters, Volume 21, Issue 8, p. 337 –338
  • DOI:  10.1049/el:19850238
  • Type: Article
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  • p. 337 –338 (2)
    We present an improved version of the twin-channel laser as a prototype for a new concept in semiconductor laser array structures with a well controlled far-field beam pattern. The laser device constitutes the first CW semiconductor laser array structure on a p-type GaAs substrate using current-blocking layers and yields improved current utilisation and efficiency over previous structures.
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Electroabsorption on room-temperature excitons in InGaAs/InGaAlAs multiple quantum-well structures
Numerical solution of silicon-clad diffused planar optical waveguides
Fast Hartley transform algorithm
  • Author(s): H.-J. Meckelburg  and  D. Lipka
  • Source: Electronics Letters, Volume 21, Issue 8, p. 341 –343
  • DOI:  10.1049/el:19850241
  • Type: Article
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  • p. 341 –343 (3)
    The discrete Hartley transform is a new tool for the analysis, design and implementation of digital signal processing algorithms and systems. It is strictly symmetrical concerning the transformation and its inverse. A new fast Hartley transform algorithm has been developed. Applied to real signals, it is faster than a real fast Fourier transform, especially in the case of the inverse transformation. The speed of operation for a fast convolution can thus be increased.
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Fast algorithm for calculation of radiation integral and its application to plane-polar near-field/far-field transformation
Tunnelling through very low barriers
Heterojunction phototransistors on n-channelled semi-insulating InP substrates
  • Author(s): U. Koren ; T.C. Penna ; P.K. Tien
  • Source: Electronics Letters, Volume 21, Issue 8, p. 346 –347
  • DOI:  10.1049/el:19850244
  • Type: Article
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  • p. 346 –347 (2)
    A new method to fabricate planar n-channelled semi-insulating (SI) InP substrate is demonstrated. Etched channels on semi-insulating substrates are filled with n-type InP crystal grown by liquid-phase epitaxy (LPE). The resulting wafers are polished again to obtain n-type channels that are periodically embedded in the semi-insulating repolished substrates. The use and application of this technique for bipolar devices on SI substrates is demonstrated by fabricating heterojunction phototransistors with LPE regrowth on these substrates.
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Single-lobe symmetric coupled laser arrays
  • Author(s): K.-L. Chen  and  S. Wang
  • Source: Electronics Letters, Volume 21, Issue 8, p. 347 –349
  • DOI:  10.1049/el:19850245
  • Type: Article
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  • p. 347 –349 (3)
    We propose a new high-power laser in which an array of N lasers is coupled to another of N + 1 lasers through Y-junctions. The field distributions of the eigenmodes in the N-array are identical to those of the supermodes in the evanescently coupled laser array. The threshold gain for the lowest-order mode is much lower than the higher-order modes. This strong mode discrimination will enable very high-power single-lobe operation.
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Operation of gyrotron oscillator with beam current unrestricted by cathode temperature
Current/voltage characteristic of CuInSe2 homojunctions
  • Author(s): I. Shih  and  C.X. Qiu
  • Source: Electronics Letters, Volume 21, Issue 8, p. 350 –351
  • DOI:  10.1049/el:19850247
  • Type: Article
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  • p. 350 –351 (2)
    Temperature-dependent forward-current/voltage characteristics of In- and Bi-diffused CuInSe2 homojunctions have been investigated over a temperature range from 200 to 300 K. It has been found that the junction current in the medium voltage range was dominated by the recombination mechanism in the depletion region. The activation energy of saturation current was about 0.95 eV, which is consistent with the energy gap value of crystalline CuInSe2.
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Single-longitudinal-mode condition for DFB lasers
Spectral linewidth of a grecc laser with added external cavity
Self-aligned MESFETs by a dual-level double-lift-off substitutional gate (DDS) technique for high-speed low-power GaAs ICs
  • Author(s): M.F. Chang ; F.J. Ryan ; R.P. Vahrenkamp ; C.G. Kirkpatrick
  • Source: Electronics Letters, Volume 21, Issue 8, p. 354 –356
  • DOI:  10.1049/el:19850250
  • Type: Article
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  • p. 354 –356 (3)
    A new self-aligned substitutional gate processing technique which involves dual-level resist patterning was developed for 75 mm (3 in)-diameter GaAs MESFETs IC fabrication. The transconductance of 1 μm gate length DDS E-MESFETs reached a maximum value of 280 mS/mm. E/R ring oscillators showed a 22 ps/gate propagation delay and a 34.5 fJ speed-power product. E/D ring oscillators had a 53 ps/gate propagation delay, a 12.5 fJ speed-power product and a power dissipation of 0.24 mW/gate at 300 K.
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Microstrip planar arrays with dielectric sphere overlays
Hybrid VLSI architecture of FIR filters using residue number systems
Erratum: Double-flame VAD process for high-rate optical preform fabrication
Erratum: Direct streak-camera observation of picosecond gain-switched optical pulses from a 1.5 μm semiconductor laser
Erratum: Observation of second-harmonic generation from a Langmuir-Blodgett monolayer of a merocyanine dye
Erratum: Direct frequency modulation of a semiconductor laser by acoustic waves

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