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Online ISSN 1350-911X Print ISSN 0013-5194

Electronics Letters

Volume 26, Issue 23, 8 November 1990

Volumes & issues:

Volume 26, Issue 23

8 November 1990

Fault equivalence in PLAs and prevention design
1 W, coherent, monolithically integrated master oscillator power amplifier
Theorem with applications in coding and matching problems
Suppression of laser frequency drifts caused by thermal transients in optical WDM packet switching systems
  • Author(s): E.G. Vicente de Vera  and  B. Glance
  • Source: Electronics Letters, Volume 26, Issue 23, p. 1930 –1932
  • DOI:  10.1049/el:19901249
  • Type: Article
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  • p. 1930 –1932 (3)
    Frequency drifts caused by laser thermal transients have been identified as a major impairment in packet switching networks using multisection tunable lasers. They are induced by the heating changes caused by current steps used to switch the carrier frequency. A method to suppress this frequency drift in a FSK-WDM direct detection system through the use of a passive equalisation circuit is presented.
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High performance p+ -gate pMOSFETs with N2O-nitrided SiO2 gate films
Electromagnetic field inside a surface current distribution
Lateral drift and recombination of photogenerated carriers in multiple quantum well hetero nipi structures
  • Author(s): C. Thirstrup ; P.L.K. Wa ; C.C. Button ; J.S. Roberts ; P.N. Robson
  • Source: Electronics Letters, Volume 26, Issue 23, p. 1935 –1936
  • DOI:  10.1049/el:19901252
  • Type: Article
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  • p. 1935 –1936 (2)
    The lateral spreading of photocarriers in a multiple quantum well hetero nipi structure is reported. The physical behaviour of the carriers is explained by a simple model. The results indicate the importance of decreasing the lateral device dimensions in order to obtain a large absorption change and a corresponding large change in the refractive index at low power levels.
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Efficient erbium-doped fibre amplifier pumped at 820 nm
  • Author(s): M. Nakazawa ; Y. Kimura ; E. Yoshida ; K. Suzuki
  • Source: Electronics Letters, Volume 26, Issue 23, p. 1936 –1938
  • DOI:  10.1049/el:19901253
  • Type: Article
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  • p. 1936 –1938 (3)
    The highest gain coefficients of 0.86 dB/mW at 1.552 μm and 0.72dB/mW at 1.534 μm are realised at a pumping wavelength of 822 nm by using an erbium-doped fibre with a relative refractive index difference as high as 1.67%, a low intrinsic loss, and an erbium ion concentration of 210 ppm. The gains at 1.552 μm reach 25 and 30 dB for launched pump powers of 30 and 40 mW, respectively.
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Derivation of Fourier transform of discrete series from z-transform
Interferometric-type polarisation splitter on Z-propagating LiNbO3:Ti
Finite-gain-insensitive circulating-delay type pseudo-N-path filter
Versatile divider circuits up to 9 GHz input-frequency realised in high-speed BICMOS
Phase-locked two-dimensional arrays of implant isolated vertical cavity surface emitting lasers
  • Author(s): H.-J. Yoo ; J.R. Hayes ; E.G. Paek ; J.P. Harbison ; L.T. Florez ; Y.-S. Kwon
  • Source: Electronics Letters, Volume 26, Issue 23, p. 1944 –1946
  • DOI:  10.1049/el:19901258
  • Type: Article
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  • p. 1944 –1946 (3)
    The fabrication and characterisation of two-dimensional phase-locked arrays of vertical cavity surface emitting lasers is reported. The three two-dimensional array structures characterised were a 2 × 3 periodic array of 10μm2 lasers, a hexagonal array and a centred hexagonal array of 5 μm hexagonal lasers. All arrays were fabricated using the same technique which was a combination of mesa etching and oxygen implantation isolation.
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Lateral Si avalanche photodiode fabricated over an etched interdigital mesa
Hybrid symmetrical condensed node for the TLM method
Adaptive dummy spectrum insertion method used in asynchronous speech scrambling
PC sampling oscillograph for subnanosecond time region
Hydrostatic pressure induced birefringence in a highly birefringent optical fibre
Opto-electronic high order feedback neural network
High power (> 100 mW), low crosstalk (< 0.4%), individually addressed laser diodes
Register insertion bus architecture for fibre optic local area networks
  • Author(s): J.M. Ott  and  A.P. Jayasumana
  • Source: Electronics Letters, Volume 26, Issue 23, p. 1957 –1959
  • DOI:  10.1049/el:19901266
  • Type: Article
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  • p. 1957 –1959 (3)
    A protocol for fibre optic local area networks, the register insertion bus (RIB), is proposed. RIB uses a folded-bus topology with an access scheme which includes the existence of two buffers in each station to hold packets that would conflict. Simulations have shown the access scheme to efficiently utilise the network with a minimum of overhead. RIB implements a fair access scheme at normal network loads but at high loads a priority scheme is implemented. An enhancement technique is discussed that will implement a fair access scheme by altering the time between transmissions based on the measured network load.
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Finite difference methods for the analysis of integrated optical waveguides
  • Author(s): R. Accornero ; M. Artiglia ; G. Coppa ; P. Di Vita ; G. Lapenta ; M. Potenza ; P. Ravetto
  • Source: Electronics Letters, Volume 26, Issue 23, p. 1959 –1960
  • DOI:  10.1049/el:19901267
  • Type: Article
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  • p. 1959 –1960 (2)
    A finite difference method based on a Crank–Nicolson discretisation procedure has been implemented and applied to the analysis of propagation of optical beams in dielectric waveguides. It is based on a new formula which takes into account the correct boundary conditions. Comparisons with the well known BPM technique show a definite improvement in computer time saving, accuracy and ease of use.
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IMPATT operation below the avalanche frequency
  • Author(s): J.-F. Luy
  • Source: Electronics Letters, Volume 26, Issue 23, p. 1960 –1962
  • DOI:  10.1049/el:19901268
  • Type: Article
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  • p. 1960 –1962 (3)
    Very high output powers are obtained with double drift IMPATT diodes at current densities which shift the avalanche frequency above the oscillation frequency: 30–40 W pulsed around 90 GHz. This operation mode cannot be explained in terms of the conventional READ theory. A numerical large signal simulation shows that avalanche multiplication over the whole diode takes place. At high current densities the double drift device behaves like a pin diode without the unfavourable breakdown of the ionisation process in the centre of the diode.
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VLSI computing architectures for Haar transform
Convergence of back-propagation in neural networks using a log-likelihood cost function
Spectral linewidth broadening in Er-doped-fibre amplifiers measured with less than 1.4 kHz linewidth light source
Generalised boundary conditions for a material sheet with both sides coated by a dielectric layer
  • Author(s): A. Büyükaksoy  and  M. Idemen
  • Source: Electronics Letters, Volume 26, Issue 23, p. 1967 –1969
  • DOI:  10.1049/el:19901272
  • Type: Article
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  • p. 1967 –1969 (3)
    Many structures which play important roles in practical applications involve planar sheets coated with dielectric layers. In order to avoid the mathematical difficulties arising from this type of multilayered structures in antennas and propagation problems one tries to replace the coated sheet by an equivalent hypothetical plane having appropriate boundary conditions. A new and general method capable of obtaining these generalised boundary conditions is presented and applied to three important particular cases where the structure consists of a resistive or conductive or impedance plane with both faces coated with dielectric layers.
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Real-time computation of the maximum likelihood criterion for some superimposed signals problems
Resequencing delay characteristics of multilink system in packet switched networks
Throughput performance of some continuous ARQ schemes with memory
  • Author(s): T.-H. Lee  and  J.-K. Hu
  • Source: Electronics Letters, Volume 26, Issue 23, p. 1972 –1973
  • DOI:  10.1049/el:19901275
  • Type: Article
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  • p. 1972 –1973 (2)
    A class of continuous ARQ schemes with memory, where multiple copies of each data block are sent contiguously instead of one single copy, and several copies of the same data block are combined to make a decision at the receiver, is considered. The throughput efficiency analysis is carried out based on the model proposed by Bruneel. Results show that the performance of the investigated ARQ schemes can be considerably improved if the receiver has some memory.
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Split-radix FHT algorithm for real-symmetric data
Low temperature dependence of the hole impact ionisation constants determined from PMOS transistors
MOCVD grown carbon-doped graded-base AlGaAs/GaAs HBTs
Nonlinear gain effects in strained-layer lasers
Reduction of intermodulation distortion of interferometric optical modulators through incoherent mixing of optical waves
Intrinsic safety of optical fibres in combustible environments
  • Author(s): P.C. Hills
  • Source: Electronics Letters, Volume 26, Issue 23, p. 1982 –1983
  • DOI:  10.1049/el:19901281
  • Type: Article
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  • p. 1982 –1983 (2)
    Contrary to widely held belief optical fibre cables are not intrinsically safe under all conditions. The results of preliminary experimental investigations into the intrinsic safety of optical fibres in combustible environments are presented. Powers in the order of 100 mW, delivered by multi-mode or single-mode optical fibres, and incident on dust particles, created explosions in combustible gas/air mixtures. Such power levels are generally higher than those used in communication systems, but are not atypical of proposed sensing systems.
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MOS triangle-to-sine wave convertor based on subthreshold operation
Weight error sensitivity of fixed point attractors in associative memory networks
Erratum: Novel multifunctional decoder for MLD codes
Erratum: Investigation of TE and TM polarised laser emission in GaInP/AlGaInP lasers by growth-controlled strain

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