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Online ISSN 1350-911X Print ISSN 0013-5194

Electronics Letters

Volume 29, Issue 8, 15 April 1993

Volumes & issues:

Volume 29, Issue 8

15 April 1993

Monolithic integration of InGaAsp/Inp lasers and heterostructure bipolar transistors by selective area epitaxy
  • Author(s): X. An ; H. Temkin ; A. Feygenson ; R.A. Hamm ; M.A. Cotta ; R.A. Logan ; D. Coblentz ; R.D. Yadvish
  • Source: Electronics Letters, Volume 29, Issue 8, p. 645 –646
  • DOI:  10.1049/el:19930432
  • Type: Article
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  • p. 645 –646 (2)
    The Letter describes the use of selective area epitaxy to prepare monolithically integrated lasers and heterostructure bipolar transistors based on InGaAsP/InP. Selective growth offers a versatile method of lateral integration of structurally dissimilar devices with the different device structures grown side by side in different growth cycles. Individual devices can be optimised separately without any performance compromise. Bipolar transistors grown on the semi-insulating current blocking layers of the buried heterostructure lasers show high gain, high breakdown voltage and excellent high current stability. Laser threshold is reached at a base current as low as 160μA and the light output is linear with current to 10mW.
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Frequency modulation locking in 980 nm strained quantum well lasers
60 GHz reflection gain based on superlattice negative differential conductance
  • Author(s): M. Hadjazi ; J.F. Palmier ; A. Sibille ; H. Wang ; E. Paris ; F. Mollot
  • Source: Electronics Letters, Volume 29, Issue 8, p. 648 –649
  • DOI:  10.1049/el:19930434
  • Type: Article
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  • p. 648 –649 (2)
    The negative differential conductance originating from miniband negative effective mass has been characterised at high frequencies in two GaAs/AlAs superlattice devices. High reflection gains reaching 10 dB at 38 GHz have been observed up to 60 GHz. These results demonstrate the excellent potentialities of superlattices for millimetre-wave oscillator applications.
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Medical ultrasound imaging using pulse compression
Thermal stability of Al/AlGaAs and Al/GaAs/AlGaAs (MBE) Schottky barriers
Defect level for non-equiprobable faults in digital ICs
AlGaInP/GaInAs strained quantum well lasers
Distributed amplifier signal shaping strategy for multigigabit digital optical transmission
  • Author(s): P.M.R.S. Moreira ; I.Z. Darwazeh ; J.J. O'Reilly
  • Source: Electronics Letters, Volume 29, Issue 8, p. 655 –657
  • DOI:  10.1049/el:19930439
  • Type: Article
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  • p. 655 –657 (3)
    A novel technique is presented for using the distributed amplifier (DA) as an active pulse shaping/filtering network by effectively constructing a transversal filter. This technique is versatile, and judicious selection of the effective stage delays and gains allows a variety of filtering functions to be implemented. The capability of the technique is illustrated with reference to a GaAs MMIC design for 10 Gbit/s.
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Analysis of a reflectarray antenna using microstrip patches of variable size
  • Author(s): D.M. Pozar  and  T.A. Metzler
  • Source: Electronics Letters, Volume 29, Issue 8, p. 657 –658
  • DOI:  10.1049/el:19930440
  • Type: Article
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  • p. 657 –658 (2)
    Microstrip reflectarrays tyically use tuning stubs on each element to adjust the phase of the reflected field. This Letter describes a new approach in which the need for tuning stubs is eliminated and phase control is achieved simply by adjusting the resonant length of the patch elements. The advantages of this approach are described, as are a full-wave analysis technique for computing the phase of the reflected field as a function of patch size and a design curve giving the change in patch size for a desired reflected field phase shift.
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Multigigabit/s pulse source based on the switching of an optical beat signal in a nonlinear fibre loop mirror
1-W CW Tm-doped fluoride fibre laser at 1.47μm
Effective bandwidth of DSPN signalling for mitigation of fading in dense scatterers
Self-assembly of three-dimensional microstructures using rotation by surface tension forces
  • Author(s): R.R.A. Syms  and  E.M. Yeatman
  • Source: Electronics Letters, Volume 29, Issue 8, p. 662 –664
  • DOI:  10.1049/el:19930444
  • Type: Article
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  • p. 662 –664 (3)
    The authors propose that automatic, parallel and selflimiting operations can be performed to reconfigure microstructures into full three-dimensional geometries, using the surface tension forces provided by molten solder to perform out-of-plane rotation of flexible hinges. Analysis is presented which indicates that the final angle of rotation can be controlled through initial solder volume, and that the forces are easily sufficient for the particular example of silicon micromechanical devices. However, the principle is general and could be applied to other materials.
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Broadly tunable InGaAsP/InP vertical-coupler filtered laser with low tuning current
High-performance InP/InGaAs heterojunction bipolar transistors with highly carbon-doped base grown by chemical beam epitaxy
  • Author(s): J.-I. Song ; C.J. Palmstrom ; B.P. Van der Gaag ; W.-P. Hong ; J.R. Hayes ; K.B. Chough
  • Source: Electronics Letters, Volume 29, Issue 8, p. 666 –667
  • DOI:  10.1049/el:19930446
  • Type: Article
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  • p. 666 –667 (2)
    InP/In0.53Ga0.47As heterojunction bipolar transistors (HBTs) using a highly carbon-doped base are reported. High carbon doping has been achieved by chemical beam epitaxy (CBE). The resulting hole concentration in the carbon-doped base is as high as 7 × 1019/cm3. To our knowledge, this is the highest doping level reported using carbon. HBTs with 20 Å spacer layer exhibited nearly ideal I-V characteristics with collector and base current ideality factor of 1.018 and 1.037, respectively. Current gain and breakdown voltage BVCEO were 7 and 6 V, respectively.
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Temperature-tunable 3.5 μm fibre laser
CMOS on-chip clock for digital signal processors
Miniaturised two-stage balanced Ku-band CPW MMIC amplifier using impedance transforming couplers
Fabrication and performances of delta-doped Si n-MESFET grown by MBE
Analysis of optical CDMA communications systems
Dynamic channel assignment with queuing in highway microcells
Microwave noise characterisation of poly-emitter bipolar junction transistors
  • Author(s): M.J. Deen  and  J.J. Ilowski
  • Source: Electronics Letters, Volume 29, Issue 8, p. 676 –678
  • DOI:  10.1049/el:19930453
  • Type: Article
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  • p. 676 –678 (3)
    The microwave noise characteristics of poly-emitter bipolar junction transistors have been evaluated in a 0.8μm silicon BiCMOS process, at frequencies between 1 and 5.6GHz, and for collector currents between 0.5 and 15mA. Using a small-signal model for the poly-emitter bipolar junction transistors, very good agreement has been obtained between measurements and calculations of both noise figure (FMIN) against frequency, and FMIN against collector current. It is found that FMIN was 2.3dB at 1 GHZ and 8.3dB at 5.6GHZ for a collector current of 5mA.
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1047 nm laser diode master oscillator Nd:YLF power amplifier laser system
  • Author(s): A.W. Yu ; M.A. Krainak ; G.L. Unger
  • Source: Electronics Letters, Volume 29, Issue 8, p. 678 –679
  • DOI:  10.1049/el:19930454
  • Type: Article
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  • p. 678 –679 (2)
    A master oscillator power amplifier (MOPA) laser transmitter system at 1047 nm wavelength using a semiconductor laser diode and a diode pumped solid state (Nd : YLF) laser (DPSSL) amplifier is described. A small signal gain of 23 dB, a near diffraction limited beam, 1 Gbit/s modulation rates and >0.6 W average power are achieved. This MOPA laser has the advantage of amplifying the modulation signal from the laser diode master oscillator (MO) with no signal degradation.
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Coaxial feed in uniaxial substrate between two finite parallel conductors
  • Author(s): G.A.E. Vandenbosch  and  A.R. van de Capelle
  • Source: Electronics Letters, Volume 29, Issue 8, p. 679 –681
  • DOI:  10.1049/el:19930455
  • Type: Article
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  • p. 679 –681 (3)
    A coaxial feed located in a uniaxial substrate between two finite parallel conductors is reduced analytically into a finite number of voltage sources over the coaxial probe. The procedure used is the same as originally developed for an isotropic substrate. The resulting expressions for both the new sources and the separated admittance component are interpreted by comparison with the isotropic case.
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Method for automated waveform analysis of transient responses in digital circuits
Modified packet reservation multiple access protocol
Long wavelength quantum well lasers with InGaAs/InP superlattice optical confinement and barrier layers
  • Author(s): A. Ginty ; J.D. Lambkin ; L. Considine ; W.M. Kelly
  • Source: Electronics Letters, Volume 29, Issue 8, p. 684 –685
  • DOI:  10.1049/el:19930458
  • Type: Article
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  • p. 684 –685 (2)
    Long wavelength, separate confinement heterostructure, ridge waveguide laser diodes using InGaAs/InP short period superlattices and InGaAs quantum wells have been demonstrated. The short period superlattices replace the more conventional quaternary alloys. These lasers have threshold current densities of 1.9kA/cm2, device efficiencies of 0.16mW/mA and a characteristic temperature T0 of 56 K.
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Multichannel coherent FSK transmission at 622 Mbit/s with synchronous intra-bit sinusoidal polarisation spreading
  • Author(s): N. Caponio ; J. Zhou ; F. Delpiano ; P. Gambini ; M. Puleo ; V. Seano ; E. Vezzoni
  • Source: Electronics Letters, Volume 29, Issue 8, p. 685 –687
  • DOI:  10.1049/el:19930459
  • Type: Article
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  • p. 685 –687 (3)
    The feasibility of polarisation insensitive multichannel coherent FSK transmission with synchronous intra-bit sinusoidal polarisation spreading has been experimentally demonstrated at 622 Mbit/s for the first time, complying with a front-end bandwidth of 3.2 GHz. Results evidenced an optimum IF filter bandwidth of four times the bit rate, and a minimum channel spacing of 11 GHz.
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Proposal of new ring access control and connection admission control method
  • Author(s): K. Kubota ; H. Yokota ; T. Tanaka
  • Source: Electronics Letters, Volume 29, Issue 8, p. 687 –688
  • DOI:  10.1049/el:19930460
  • Type: Article
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  • p. 687 –688 (2)
    A new ring access control method is proposed for an ATM ring network. In this method, higher priority traffic which requires strict quality of service can be transmitted with no cell loss, by executing connection admission control. Lower priority traffic is transmitted using that part of the bandwidth not used for higher priority traffic. In this way, ring use is improved. A simulation is used to demonstrate these characteristics.
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Improvement of bidirectional associative memories by using correlation significance
  • Author(s): D.-L. Lee  and  W.-J. Wang
  • Source: Electronics Letters, Volume 29, Issue 8, p. 688 –690
  • DOI:  10.1049/el:19930461
  • Type: Article
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  • p. 688 –690 (3)
    A correlation significance technique is introduced, which uses the significances between the training associations and between the neurons of the different fields, such that the storage capacity of Kosko bidirectional associative memories (BAMs) is improved. Based on the gradient descent method, an error function is constructed such that the maximal number of stored associations which are successfully recalled can be obtained. Finally computer simulations demonstrate that the proposed method has much better storage capacity than the existing methods.
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Millimetre wave fibre-optic PSK subcarrier transmission at 35 GHz over 6.3 km using a grating external cavity semiconductor laser
Integrated optic laser emitting at 906, 1057, and 1358 nm
Neural learning in analogue hardware: effects of component variation from fabrication and from noise
Achievable performance of autonomous SIR-based power control
  • Author(s): S. Ariyavisitakul
  • Source: Electronics Letters, Volume 29, Issue 8, p. 694 –696
  • DOI:  10.1049/el:19930465
  • Type: Article
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  • p. 694 –696 (3)
    The Letter investigates the achievable performance in a TDMA system of an autonomous power control technique which relies only on a simple fixed-step feedback adjustment algorithm. Simulation results indicate that this simple power control technique can perform nearly as well as ideal signal-to-interference ratio (SIR) balancing/call removal, yielding a possible increase in spectrum efficiency of at least three times compared to a system without power control. The work is targeted towards understanding the traffic capacity and deployment implications to local exchange networks of wireless technology that could provide access to those networks.
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1/f noise and interface trap density in high field stressed pMOS transistors
PRMA efficiency in adaptive transceivers
  • Author(s): L. Hanzo ; J.C.S. Cheung ; R. Steele
  • Source: Electronics Letters, Volume 29, Issue 8, p. 697 –699
  • DOI:  10.1049/el:19930467
  • Type: Article
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  • p. 697 –699 (3)
    The effects of different speech source rates and various number of modulation levels on packet reservation multiple access (PRMA) efficiency in an adaptive transceiver are investigated under the constraint of fixed channel bandwidth and benign cochannel interference in office type cordless telecommunications (CT) environments. The number of PRMA users supported in a 200 kHz frequency slot ranges from 17 to 103, the required user bandwidth is between 11.8 and 1.94 kHz, and the number of PRMA users per slot is between 1.7 and 1.94, respectively.
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Processing of specular echoes from planar reflectors in airborne sonar data
Low threshold-current, wide tuning-range, butt-joint DBR laser grown with four MOVPE steps
Bit-rate flexible all-optical demultiplexing using a nonlinear optical loop mirror
Adaptive speech coding with DCT and neural net vector quantisation
Direct comparison of InGaAs/InGaAlAs and InGaAs/InGaAsP quantum well modulators
  • Author(s): B.J. Hawdon ; T. Tütken ; A. Hangleiter ; R.W. Glew ; J.E.A. Whiteaway
  • Source: Electronics Letters, Volume 29, Issue 8, p. 705 –707
  • DOI:  10.1049/el:19930472
  • Type: Article
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  • p. 705 –707 (3)
    Using picosecond pump-probe measurements, InGaAs/ InGaAlAs and InGaAs/InGaAsP quantum well modulator structures are compared directly. It is found that the shortpulse exciton saturation intensity for the Al-based structure is at least 10 times that for the P-based system. The more efficient carrier sweep-out observed in the Al-based modulator is due to the lower valence-band discontinuity, making it by far the more attractive structure for high-power applications.
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Hydrogenated amorphous silicon-carbide thin-film light-emitting diode with quantum-well-injection structure
  • Author(s): T.-S. Jen ; J.-Y. Chen ; N.-F. Shin ; J.-W. Hong ; C.-Y. Chang
  • Source: Electronics Letters, Volume 29, Issue 8, p. 707 –708
  • DOI:  10.1049/el:19930473
  • Type: Article
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  • p. 707 –708 (2)
    To improve the electroluminescence (EL) intensity of the hydrogenated amorphous silicon carbide (a-SiC : H) pin thin-film light-emitting diode (TFLED), a quantum-well-injection (QWI) structure has been incorporated into the i-layer of an a-SiC : H pin TFLED at the p-i interface. The obtained brightness of this QWI TFLED is 256cd/m2 at an injection current density of 800mA/cm2, which is about three orders of magnitude higher than the brightness of an a-SiC : H pin TFLED. Also, a comparatively lower EL threshold voltage of 6 V was observed for this a-SiC : H QWI TFLED.
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Determination of depth of proton exchanged layer in LiNbO3 from laser induced pyroelectric signals
  • Author(s): S. Tuli  and  A.B. Bhattacharyya
  • Source: Electronics Letters, Volume 29, Issue 8, p. 708 –710
  • DOI:  10.1049/el:19930474
  • Type: Article
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  • p. 708 –710 (3)
    A new nondestructive technique for the determination of the depth of the proton exchanged (PE) layer in LiNbO3 is reported. The techniques relies on the difference in phase of measured pyroelectric voltages, induced by a modulated laser beam incident on the exchanged and unexchanged regions. Measurements of PE layer thickness in a Z-cut LiNbO3 sample have been corroborated by prevalent, more elaborate, optical characterisation techniques.
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Narrow bandpass single layer frequency selective surfaces
Complex modes in circular chirowaveguides
Novel sub-100 nm thin film transistors
Formation of optical slab waveguides using thermal oxidation of SiOx
  • Author(s): Q. Lai ; J. Schmid ; W. Hunziker ; H. Melchior ; P. Pliska
  • Source: Electronics Letters, Volume 29, Issue 8, p. 714 –716
  • DOI:  10.1049/el:19930478
  • Type: Article
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  • p. 714 –716 (3)
    A novel method for the fabrication of optical slab waveguides is presented. After growth of the base cladding by thermal oxidation and deposition of the core layer of the waveguide by PECVD of SiOx, the top cladding layer is formed from the core layer material by an additional thermal oxidation which transforms SiOx, into SiO2. With this simple technology, contaminations and rough interfaces between core and cladding are avoided. Low propagation losses and good matching to optical fibres are achieved.
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Novel calibration technique employing a spread-spectrum tone for mobile satellite systems
  • Author(s): G.E. Corazza ; C. Ferrarelli ; F. Vatalaro
  • Source: Electronics Letters, Volume 29, Issue 8, p. 716 –718
  • DOI:  10.1049/el:19930479
  • Type: Article
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  • p. 716 –718 (3)
    A calibration technique based on a low-power spread-spectrum tone to assist demodulation is presented. The technique does not impose any requirements on signal modulation, spectral shaping, nor on channel spacing, and is highly spectrum efficient. The performance is analysed in the presence of cochannel and adjacent channel interference, diffused-multipath fading and additive white Gaussian noise, and results are presented for M-PSK. (M = 2, 4, 8).
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Optical pulse generation with high repetition rate by sinusoidally-driven InGaAs/InAIAs multiquantum well modulator
Design of three channel complementary filters as a weighted sum of two allpass sections
  • Author(s): S.R. Pillai
  • Source: Electronics Letters, Volume 29, Issue 8, p. 719 –721
  • DOI:  10.1049/el:19930481
  • Type: Article
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  • p. 719 –721 (3)
    The design of power complementary filters for multichannel sub-bands using a minimum number of allpass sections is investigated. In particular it is shown that three power complementary niters, for example a lowpass, a bandpass and a highpass combination, can be generated from two allpass filters. From a hardware design point of view, these new power complementary structures are desirable, because the actual number of filters to be implemented is comparatively small.
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Demonstration of all-optical demultiplexing at 1555 nm with an AlGaAs directional coupler
Low-threshold operation of tensile-strained GaInP/AlGaInP MQW LDs emitting at 625 nm
  • Author(s): T. Tanaka ; H. Yanagisawa ; M. Takimoto ; S. Yano ; S. Minagawa
  • Source: Electronics Letters, Volume 29, Issue 8, p. 722 –724
  • DOI:  10.1049/el:19930483
  • Type: Article
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  • p. 722 –724 (3)
    A low threshold current of 47 mA at 20°C has been obtained in a tensile-strained index-guided AlGaInP LD emitting at 625nm, which has an active region consisting of five 8 nm-thick QWs with a lattice mismatch of −0.9%. It is shown that optimisation of the tensile-strained QW structure is very useful in improving the performance of AlGaInP LDs at wavelengths shorter than 630 nm.
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Microwave power InP/InGaAs/InP double-heterojunction bipolar transistors
  • Author(s): J.-I. Song ; W.-P. Hong ; R. Bhat ; K.B. Chough ; J.R. Hayes ; B. Sugeng ; C.J. Wei ; J.C.M. Hwang
  • Source: Electronics Letters, Volume 29, Issue 8, p. 724 –725
  • DOI:  10.1049/el:19930484
  • Type: Article
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  • p. 724 –725 (2)
    The first demonstration of the microwave power performance of an InP/InGaAs/InP double-heterojunction bipolar transistor (DHBT) is reported. A collector-emitter breakdown voltage in excess of 14 V was achieved with a current gain of 70. A maximum output power density of approximately 1 W/mm emitter length was measured at 5 GHz with a power gain of 8 dB. The results show the significant potential of InP based DHBTs for microwave power applications.
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Erratum: Simple method for determining 3-D TLM nodal scattering in nonscalar problems
Erratum: Circuit performance of low temperature CMOS polysilicon TFT operational amplifiers
Erratum: Reduced intermodulation-free dynamic range in gain-lever lasers
Erratum: Variable time delay of microwave signals using high dispersion fibre

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