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Online ISSN 1350-911X Print ISSN 0013-5194

Electronics Letters

Volume 29, Issue 7, 1 April 1993

Volumes & issues:

Volume 29, Issue 7

1 April 1993

Phased array error correction scheme
Low threshold continuous operation of InGaAs/InGaAsP quantum well lasers at ~2.0 μm
  • Author(s): S. Forouhar ; S. Keo ; A. Larsson ; A. Ksendzov ; H. Temkin
  • Source: Electronics Letters, Volume 29, Issue 7, p. 574 –576
  • DOI:  10.1049/el:19930386
  • Type: Article
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  • p. 574 –576 (3)
    The first low threshold continuous operation of InGaAs strained layer quantum well lasers at ~2.0 μm is reported. The threshold current density of 5 μm wide and 1.5 mm long ridge waveguide lasers was less than 380 A/cm2. The external differential quantum efficiency of 1 mm long lasers was as high as 15% and laser operation was observed at temperatures as high as 50°C. The lasers are characterised by T0 = 54°C which is the highest characteristic temperature ever achieved at this wavelength in any material system.
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Compensation of fibre chromatic dispersion by spectral inversion
Effect of scene cuts on ATM video
  • Author(s): M. Ghanbari  and  V. Seferidis
  • Source: Electronics Letters, Volume 29, Issue 7, p. 578 –579
  • DOI:  10.1049/el:19930388
  • Type: Article
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  • p. 578 –579 (2)
    The effect of cell loss on ATM video is investigated. It is shown that the quality of affected pictures mainly depends on the position of the lost cells in an image sequence. Picture degradation at scene cuts is much more objectionable than in areas without scene cuts. The effect of such degradation may last for more than 5 s, requiring either a lightly loaded network, or video codecs that can tolerate high cell loss rates.
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Strain effect on K factor, differential gain and nonlinear gain coefficient for InGaAs/InGaAsP strained multiquantum well lasers
  • Author(s): J.-I. Shimizu ; A. Kimura ; K. Naniwae ; M. Nido ; S. Murata ; A. Tomita ; A. Suzuki
  • Source: Electronics Letters, Volume 29, Issue 7, p. 579 –581
  • DOI:  10.1049/el:19930389
  • Type: Article
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  • p. 579 –581 (3)
    The strain effect on the K factor, the differential gain and the nonlinear gain coefficient for InGaAs/InGaAsP tensile-strained and compressive-strained multiquantum well (MQW) lasers is experimentally investigated from the intrinsic modulation response. The differential gain increases with an increase in strain for both types of laser. The strain dependence of the nonlinear gain coefficient is not as high as that of the differential gain. Therefore, the K factor for strained MQW lasers mainly results from the differential gain.
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Sputter-deposited erbium-doped Y2O3 active optical waveguides
Novel PN-code tracking loop with periodic discriminator characteristic
Low threshold voltage vertical cavity surface-emitting laser
  • Author(s): K.L. Lear ; S.A. Chalmers ; K.P. Killeen
  • Source: Electronics Letters, Volume 29, Issue 7, p. 584 –586
  • DOI:  10.1049/el:19930392
  • Type: Article
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  • p. 584 –586 (3)
    Vertical-cavity surface emitting laser diodes with threshold voltages as low as 1.48 V are demonstrated. The devices have low-resistance epitaxial mirrors, and current passes through the entire mirror stack. The low threshold voltage results from both low threshold current densities and mirrors with low resistivities even at low current densities. The laser fabrication sequence is relatively quick and simple and allows for the rapid characterisation of vertical-cavity surface-emitting laser material.
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Extraction of physical device dimensions of SOI MOSFETs from gate capacitance measurements
Polarisation-independent switching in a nonlinear optical loop mirror by a dual-wavelength switching pulse
Selective metallisation on Ge for ohmic contact to GaAs
Measurement of 1.3 μm/1.0 μm branching ratio in Pr3+-doped fluoride fibre
Fast CMOS multilevel current comparator
670 nm semiconductor laser diode pumped erbium-doped fibre amplifiers
Lossy model for EM scattering from superconducting film deposited on discretised LaAlO3 substrate
  • Author(s): A.S. Rong ; Y.Y. Wang ; Z.L. Sun ; P.H. Wu
  • Source: Electronics Letters, Volume 29, Issue 7, p. 595 –596
  • DOI:  10.1049/el:19930399
  • Type: Article
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  • p. 595 –596 (2)
    A lossy model is presented for the electromagnetic scattering from the superconducting film YBa2Cu3O7−x deposited on discretised LaAlO3 substrate. The model is based on the integral equation using the dyadic Green function. The superconducting film is characterised by an impedance matrix instead of a surface impedance, and the substrate by a complex dielectric constant. The scattering parameters as functions of the operating temperature, the thickness of the superconducting film and the dielectric loss of the substrate are given, which have hitherto not been presented in the literature.
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Kalman algorithm frequency estimator for dynamic Doppler shift environments
  • Author(s): H.J. Clayton ; P. Fines ; A.H. Aghvami
  • Source: Electronics Letters, Volume 29, Issue 7, p. 597 –598
  • DOI:  10.1049/el:19930400
  • Type: Article
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  • p. 597 –598 (2)
    A Kalman algorithm (KA) frequency estimation scheme for digital communications systems is presented and the performance compared to a maximum likelihood frequency detector (MLFD) [1] and an extended Kalman algorithm (EKA) as a frequency estimator [2]. A fourth order Kalman filter computes the optimum operating bandwidth based on statistical information about a received signal, which in this case experiences significant Doppler shift, change in Doppler shift rate and AWGN. Such a scheme finds application in all environments that experience dynamic Doppler shift, such as transmission from non-geostationary satellites and quickly manoeuvring vehicles.
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Efficient implementation of all maximally flat FIR filters of a given order
Dual-wavelength photonic network for wide-area digital TV and data transport
Image compression by edge pattern learning using multilayer perceptrons
  • Author(s): G. Qiu ; M.R. Varley ; T.J. Terrell
  • Source: Electronics Letters, Volume 29, Issue 7, p. 601 –603
  • DOI:  10.1049/el:19930403
  • Type: Article
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  • p. 601 –603 (3)
    A new method for image compression using several multilayer perceptron (MLP) networks is described. Images to be compressed are divided into small sub-image blocks which are processed independently. The MLPs are used to code residual image blocks, formed by subtracting the quantised block mean value from each pixel in the original block. To reduce edge degradation in the reconstructed images, several MLPs are used, each representing a different orientation of edge information. Simulation results are presented which demonstrate the effectiveness of this new technique.
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Orientation accuracy of edge detection operators acting on binary and saturated grey-scale images
Intervalence band absorption coefficient measurements in bulk layer, strained and unstrained multiquantum well 1.55 μm semiconductor lasers
  • Author(s): I. Joindot  and  J.L. Beylat
  • Source: Electronics Letters, Volume 29, Issue 7, p. 604 –606
  • DOI:  10.1049/el:19930405
  • Type: Article
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  • p. 604 –606 (3)
    Measurements are reported of intervalence band absorption (IVBA) coefficient k0 in three types of active layer structure: bulk, unstrained (MQW) and strained multiquantum wells. The IVBA measurements are performed by observing the spontaneous emission from the uncleaved facets of DCPBH Fabry-Perot lasers. k0 = (3.7 ± 0.3) × 10−17 cm2 is obtained for bulk, (1.4 ± 0.2) × 10−16 cm2 for MQW unstrained and (3.5 ± 0.3) × 10−17 cm2 for strained MQW structures.
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Tensile strained QW structure for low-threshold operation of short-wavelength AlGaInP LDs emitting in the 630nm band
Periodic solutions of Toda lattice in loop nonlinear transmission line
Systolic array algorithm for the Hopfield neural network guaranteeing convergence
  • Author(s): S. Eun ; J. Kim ; S.R. Maeng ; H. Yoon
  • Source: Electronics Letters, Volume 29, Issue 7, p. 609 –611
  • DOI:  10.1049/el:19930408
  • Type: Article
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  • p. 609 –611 (3)
    It has been frequently reported that the Hopfield neural network operating in discrete-time and parallel update mode will not converge to a stable state, which inhibits the parallel execution of the model. In the Letter, a systolic array algorithm for the parallel simulation of the Hopfield neural network is proposed which guarantees the convergence of the network and achieves linear speedup as the number of processors is increased.
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High responsivity 1.3 μm transceiver module for low cost optical half-duplex transmission
  • Author(s): J. Semo ; H. Nakajima ; C. Kazmierski ; N. Kalonji ; J. Landreau ; B. Pierre
  • Source: Electronics Letters, Volume 29, Issue 7, p. 611 –612
  • DOI:  10.1049/el:19930409
  • Type: Article
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  • p. 611 –612 (2)
    A pigtailed transceiver module which exhibits a record responsivity of 0.5 A/W is described. A single laser chip of Fabry–Perot type V-on-U-groove (VUG) laser is packed in a butterfly type package. By improving the fibre-chip coupling, a responsivity as high as 0.5 A/W is demonstrated together with a bandwidth of 1.5 GHz. The power penalty, compared with that of a pin photodiode within the same experimental configuration, is only 1.2 dB at 800 Mbit/s.
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New current-conveyor-based single-resistance-controlled/voltage-controlled oscillator employing grounded capacitors
  • Author(s): D.R. Bhaskar  and  R. Senani
  • Source: Electronics Letters, Volume 29, Issue 7, p. 612 –614
  • DOI:  10.1049/el:19930410
  • Type: Article
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  • p. 612 –614 (3)
    A new current conveyor (CC) based minimum-component oscillator structure has been proposed which provides the following advantageous features over the previously known minimum-component designs: (i) noninteracting control of frequency of oscillation through a single grounded resistor, (ii) easy convertibility into a voltage-controlled oscillator (iii) use of two grounded capacitors as preferred for IC implementation, (iv) availability of a buffered output, and (v) very good frequency stability.
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3 Gbit/s optically preamplified direct detection DPSK receiver with 116 photon/bit sensitivity
  • Author(s): T.J. Paul ; E.A. Swanson ; J.C. Livas ; R.S. Bondurunt ; R.J. Magliocco
  • Source: Electronics Letters, Volume 29, Issue 7, p. 614 –615
  • DOI:  10.1049/el:19930411
  • Type: Article
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  • p. 614 –615 (2)
    For the first time experimental bit error rate curves are presented for an optically preamplified direct detection differential phase shift keying (DPSK) communication link. DPSK offers ̃6 dB peak power sensitivity improvement over more traditionally optically preamplified on/off keying (OOK). Using an erbium doped fibre preamplifier, a fibre Fabry–Perot filter, an optical DPSK demodulator consisting of a fibre-optic Mach–Zehnder interferometer with a 1 bit differential delay, and a balanced receiver, a sensitivity of 116 photon/bit was obtained. To the authors' knowledge these results represent the first demonstration of optically preamplified DPSK with better sensitivity than previously reported multigigabit per second heterodyne DPSK and ̃3 dB more sensitivity on a peak power basis than previously reported preamplified OOK systems.
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0.2 μm gate length pseudomorphic HIGFET using novel selfaligned TiPtAu/WN T-gate technology for high-speed digital and millimetre wave applications
  • Author(s): H. Fawaz ; J. Gest ; M. François ; H. El-Idrissi ; J. Zimmermann
  • Source: Electronics Letters, Volume 29, Issue 7, p. 615 –617
  • DOI:  10.1049/el:19930412
  • Type: Article
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  • p. 615 –617 (3)
    A selfaligned refractory gate HIGFET technology is described. A three-layer resist process has been used for gate TiPtAu thickening, making high-speed digital structures compatible with low noise microwave applications. Pseudomorphic HIGFETs with 0.2 μm gate length exhibit a maximum transconductance of 660mS/mm and a maximum oscillation frequency fmax of 100 GHz.
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Generalised Elmore delay expression for distributed RC tree networks
Assessment of GTD for mobile radio propagation prediction
Scale and rotation invariant pattern recognition using complex-log mapping and augmented second order neural network
  • Author(s): H.Y. Kwon ; B.C. Kim ; D.S. Cho ; H.Y. Hwang
  • Source: Electronics Letters, Volume 29, Issue 7, p. 620 –621
  • DOI:  10.1049/el:19930415
  • Type: Article
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  • p. 620 –621 (2)
    A scale and rotation invariant pattern recognition system using complex-log mapping (CLM) and an augmented second order neural network (SONN) is proposed. CLM is very useful for extracting the scale and rotation invariant features. The results are, however, given in a wrap-around translated form. This problem is solved with an augmented SONN. Experimental results show that the proposed system has improved recognition performance.
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Increase in photosensitivity in silica-based optical waveguides on silicon
  • Author(s): Y. Hibino ; M. Abe ; H. Yamada ; Y. Ohmori ; F. Bilodeau ; B. Malo ; K.O. Hill
  • Source: Electronics Letters, Volume 29, Issue 7, p. 621 –623
  • DOI:  10.1049/el:19930416
  • Type: Article
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  • p. 621 –623 (3)
    An increase in the photoinduced refractive-index change Δn in silica-based optical waveguides on silicon is described. The increase is attained by the consolidation of a core film in a reducing atmosphere. A maximum Δn of 3.9 × 10−4 is obtained for the TE mode by UV laser irradiation at 248nm. This is four times larger than that in conventional waveguides.
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Composite n-MOSFET for submicrometre circuits
  • Author(s): D.Y. Ge ; N. Hwang ; L. Forbes
  • Source: Electronics Letters, Volume 29, Issue 7, p. 623 –625
  • DOI:  10.1049/el:19930417
  • Type: Article
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  • p. 623 –625 (3)
    This Letter proposes a new composite n-MOS device to replace conventional n-channel devices in submicrometre amplifier circuits whenever a large drain-source voltage is encountered. The composite device improves the lifetime of a simple amplifier by eight orders of magnitude. Increasing the device channel length to reduce the effects of hot electron degradation has also been investigated as an alternative in contrast to the composite device, but is demonstrated to be an inferior design choice.
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Imaging system based on electromagnetic tomography (EMT)
Gallium arsenide bulk acoustic wave resonators fabricated using sol-gel technology
High performance double-doped InAlAs/InGaAs/InP heterojunction FET with potential for millimetre-wave power applications
  • Author(s): N. Iwata ; M. Tomita ; M. Kuzuhara
  • Source: Electronics Letters, Volume 29, Issue 7, p. 628 –629
  • DOI:  10.1049/el:19930420
  • Type: Article
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  • p. 628 –629 (2)
    Lattice matched InAlAs/InGaAs/InP heterojunction field-effect transistors (HJFETs), which have carrier supplying layers on and beneath the undoped InGaAs channel layer, have been successfully fabricated. A selective recess of the InGaAs channel edge at a mesa sidewall together with the use of a wide recess gate structure leads to a 5.7 V gate-drain breakdown voltage without kink effects. The fabricated HJFET with a 0.15 × 100 μm2 T-shaped gate exhibits a 700mA/mm maximum drain current, a voltage gain of 14, and a 345 GHz maximum frequency of oscillation.
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Bit error ratio assessment capability of bit interleaved parity in presence of error bursts
Spurious response sensitivity of two-way transceivers related to the 3rd-order nonlinearity of SAW filters
  • Author(s): M. Hikita ; N. Shibagaki ; T. Tabuchi ; T. Akagi
  • Source: Electronics Letters, Volume 29, Issue 7, p. 631 –632
  • DOI:  10.1049/el:19930422
  • Type: Article
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  • p. 631 –632 (2)
    The spurious response sensitivities (SRSs) of two-way radio transceivers, as determined from the 3rd-order nonlinearities of SAW filters, are compared using two types of filter, the IIDT-type and a newly-developed SAW-resonator-coupled type, in high-power (~1 W) applications. The latter type is shown to result in an SRS which satisfies system specifications with sufficient margins.
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Four state binary QAM trellis code better than known codes
Single photon interference in 10 km long optical fibre interferometer
  • Author(s): P.D. Townsend ; J.G. Rarity ; P.R. Tapster
  • Source: Electronics Letters, Volume 29, Issue 7, p. 634 –635
  • DOI:  10.1049/el:19930424
  • Type: Article
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  • p. 634 –635 (2)
    Single-photon interference fringes with greater than 90% visibility were measured using a 10 km long optical fibre interferometer. The experiment employed a pulsed semiconductor laser source operating at a wavelength of 1.3 μm and a novel single-photon counting scheme using high-speed germanium avalanche photodiodes. Interferometers of this type could form the basis of future quantum cryptography systems.
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Trellis coded modulation schemes for shadowed Rician fading channels
Guided quasistatic fields in electromagnetic measurement-while-drilling
  • Author(s): M.Y. Xia  and  Z.Y. Chen
  • Source: Electronics Letters, Volume 29, Issue 7, p. 637 –639
  • DOI:  10.1049/el:19930426
  • Type: Article
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  • p. 637 –639 (3)
    The quasistatic fields of extremely low frequencies (ELF) employed to communicate from underground to the ground surface in the electromagnetic measurement-while-drilling (EM-MWD) system are investigated. Three types of well, the vertical well, directional well and horizontal well, are considered. Computed results are obtained for various parameters, including the operating frequencies and the Earth's conductivities. It is demonstrated that long drill strings have a guiding effect which is advantageous to the data transmission.
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4.5 Gbit/s modelocked extended-cavity laser with a monolithically integrated electroabsorption modulator
  • Author(s): P.B. Hansen ; G. Raybon ; U. Koren ; B.I. Miller ; M.G. Young ; M.A. Newkirk ; M.-D. Chien ; B. Tell ; C.A. Burrus
  • Source: Electronics Letters, Volume 29, Issue 7, p. 639 –640
  • DOI:  10.1049/el:19930427
  • Type: Article
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  • p. 639 –640 (2)
    An electroabsorption modulator has been monolithically integrated with an extended-cavity laser, which incorporates a Bragg reflector. Actively modelocked at the fundamental cavity resonance frequency of 4.5 GHz, the laser provides a train of 6.3 ps pulses with a centre wavelength of 1544 nm onto which data is encoded by the modulator. This 4.5 Gbit/s single-chip transmitter is suitable for systems employing short optical pulses.
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Analysis of BER of 16QAM signal in AM/16QAM hybrid optical transmission system
  • Author(s): K. Maeda ; H. Nakata ; K. Fujito
  • Source: Electronics Letters, Volume 29, Issue 7, p. 640 –642
  • DOI:  10.1049/el:19930428
  • Type: Article
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  • p. 640 –642 (3)
    The BER of a 16QAM signal in an AM/16QAM hybrid optical transmission system is tested. A floor is observed in the measured BER. Such a BER floor is due to ‘impulsive distortion’ caused by clipping. The BER is calculated based on the Middleton class A model, under the supposition that a statistical-physical model of ‘impulsive distortion’ is similar to that of impulse noise. The calculated and experimental results are in good agreement.
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Electric parameter evolutions against gatelength and bias in ultrashort gate AlGaAs/GaAs HEMTs
  • Author(s): Y. Jin-Delorme ; A. de Lustrac ; P. Crozat ; K. Yazbek ; R. Adde ; G. Vernet ; Y. Jin ; B. Etienne ; H. Launois
  • Source: Electronics Letters, Volume 29, Issue 7, p. 642 –643
  • DOI:  10.1049/el:19930429
  • Type: Article
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  • p. 642 –643 (2)
    The electric parameter evolutions of state of the art ultrashort gate planar doped AlGaAs/GaAs HEMTs are studied against gatelength lg = 0.4–0.1 μm and bias. The best value of maximum intrinsic transconductance obtained is gm0max = 800mS/mm at lg = 0.15 μm and the measured cutoff frequency is ft = 125 GHz at lg = 0.1 μm.
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Erratum: Application of high-quality SiO2 grown by multipolar ECR source to Si/SiGe MISFET
Erratum: Highly reliable 200 mW AlGaAs laser diode with fundamental transverse mode

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