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Online ISSN 1350-911X Print ISSN 0013-5194

Electronics Letters

Volume 27, Issue 18, 29 August 1991

Volumes & issues:

Volume 27, Issue 18

29 August 1991

Bandwidth efficient operation of phase diversity reception compared with heterodyne reception
10 Gbit/s optical front end using Si-bipolar preamplifier IC, flipchip APD, and slant-end fibre
  • Author(s): H. Hamano ; T. Yamamoto ; Y. Nishizawa ; Y. Oikawa ; H. Kuwatsuka ; A. Tahara ; K. Suzuki ; A. Nishimura
  • Source: Electronics Letters, Volume 27, Issue 18, p. 1602 –1605
  • DOI:  10.1049/el:19911004
  • Type: Article
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  • p. 1602 –1605 (4)
    An optical front end for a 10 Gbit/s optical receiver has been fabricated that features a 10 GHz Si preamplifier IC, a flip-chip APD with an 80 GHz gain-bandwidth product, and slant-end fibre optical coupling. Hybrid construction consisting of a flipchip APD mounted directly on the preamplifier chip minimises interconnect parasitics, and slant-end fibre optical coupling simplifies flat-package assembly of chip and fibre. An optical sensitivity of −23 dBm was achieved.
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Figures of merit for doped fibre amplifiers in 1300 nm and 1550 nm windows
Efficient electroabsorption in InGaAsP/InGaAsP MQW optical waveguide
High frequency saturated CMOS floating resistor for fully-differential analogue signal processors
  • Author(s): M. Steyaert ; J. Silva-Martinez ; W. Sansen
  • Source: Electronics Letters, Volume 27, Issue 18, p. 1609 –1611
  • DOI:  10.1049/el:19911007
  • Type: Article
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  • p. 1609 –1611 (3)
    A floating resistor on a current source technique is introduced. All the transistors are saturated leading to higher frequency response than previously proposed techniques. Simulated results, using HSPICE level 3, for a 214 kΩ floating resistor have shown a −3 dB frequency of the order of 1 GHz. Its total harmonic distortion at 10.7 MHz and including 2% worst case transistor mismatches is less than –62 dB for fully differential applied signals up to 2 V peak to peak.
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New de-embedding method for millimetre-wave bipolar transistor S-parameter measurement
  • Author(s): N.L. Wang ; W.J. Ho ; J.A. Higgins
  • Source: Electronics Letters, Volume 27, Issue 18, p. 1611 –1612
  • DOI:  10.1049/el:19911008
  • Type: Article
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  • p. 1611 –1612 (2)
    An improved de-embedding method is used to measure the intrinsic HBT S parameters to millimetre wave frequencies. Standard twelve-error element models and dummy pads with resistors as calibration standards are used. This new method correctly reveals the effect from the extra delay time, parasitic capacitance, and parasitic inductance introduced by the layout and enables the performance at millimetre-wave frequencies to be accurately predicted.
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Video distribution system with 40 AM-VSB channels and 22 dB link budget
Universal active current filters using single second-generation current conveyor
  • Author(s): C.-M. Chang
  • Source: Electronics Letters, Volume 27, Issue 18, p. 1614 –1617
  • DOI:  10.1049/el:19911010
  • Type: Article
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  • p. 1614 –1617 (4)
    Two novel universal active current filters, one of which has multiple outputs and the other of which has a single output and high output impedance, employing a single negative second-generation current conveyor, three position-fixed capacitors and four/five position-fixed resistors are proposed. The proposed networks with the advantages of low passive sensitivities can obtain second-order lowpass, bandpass, highpass, notch and allpass current signals by adjusting the magnitudes of a grounded resistor and a grounded capacitor provided that another resistor is separable. The resonance angular frequency and quality factor are insensitive to the current tracking error of the nonideal CCII–.
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Novel pseudomorphic InGaAs/AlGaAs SISFET and HIGFET structures for direct coupled FET logic
  • Author(s): R.T. Carline ; C.G. Morton ; D.W.E. Allsopp
  • Source: Electronics Letters, Volume 27, Issue 18, p. 1617 –1619
  • DOI:  10.1049/el:19911011
  • Type: Article
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  • p. 1617 –1619 (3)
    Novel methods of implementing direct coupled FET logic using GaAs-based pseudomorphic quasisquare quantum well HFETs have been identified from selfconsistent calculations of their charge control curves. The techniques are based on a new depletion-mode SISFET structure in which the n+ contact layer has a wider bandgap than the channel layer. Enhancement mode driver FETs are obtained by replacing the n+ contact with a Schottky barrier to create a HIGFET.
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High frequency GaAs switched capacitor filter implemented with GaAs insulated gate FET switches
  • Author(s): J.L. Luck ; J.T. Taylor ; J.G. Swanson ; D.G. Haigh
  • Source: Electronics Letters, Volume 27, Issue 18, p. 1619 –1620
  • DOI:  10.1049/el:19911012
  • Type: Article
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  • p. 1619 –1620 (2)
    A switched capacitor filter implemented with 5μn GaAs IGFET switches and GaAs MESFET operational amplifiers is presented. The circuit is clocked at 25MHz. By scaling to 1μm IGFETs, a switching speed of about 625 MHz should be attainable. Use of GaAs IGFET switches is shown to greatly reduce power consumption and complexity of the circuit. The low frequency switching instability of the GaAs IGFET is shown to be of no consequence in this application.
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Colliding pulse phase detector for picosecond resolution timing measurement
Electro-optic sampling of optoelectronically phase-locked 10.0 GHz microwave signals using semiconductor laser diodes
Inexact match associative memory cell
Determination of minimal cost one-dimensional linear hybrid cellular automata
Alternative built-in self-test (BIST) structures for analogue circuit fault diagnosis
Low-threshold and narrow-linewidth 1.5 μm compressive-strained multiquantum-well distributed-feedback lasers
  • Author(s): C.E. Zah ; R. Bhat ; S.G. Menocal ; F. Favire ; P.S.D. Lin ; A.S. Gozdz ; N.C. Andreadakis ; B. Pathak ; M.A. Koza ; T.P. Lee
  • Source: Electronics Letters, Volume 27, Issue 18, p. 1628 –1630
  • DOI:  10.1049/el:19911018
  • Type: Article
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  • p. 1628 –1630 (3)
    1.5 μm compressive-strained multiquantum-well distributed-feedback lasers have been fabricated and characterised. 5.5 mA threshold current, 1 MHz mW linewidth-power product, and 600 kHz minimum linewidth were measured on 500 μm long devices. Measured threshold current as low as 2.2 mA was also obtained on 150 μm long devices. Both low threshold and narrow linewidth are attributed to the reduced transparency current and linewidth enhancement factor due to the effect of strain.
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Monolithic integration of photodetector with vertical cavity surface emitting laser
  • Author(s): G. Hasnain ; K. Tai ; Y.H. Wang ; J.D. Wynn ; K.D. Choquette ; B.E. Weir ; N.K. Dutta ; A.Y. Cho
  • Source: Electronics Letters, Volume 27, Issue 18, p. 1630 –1632
  • DOI:  10.1049/el:19911019
  • Type: Article
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  • p. 1630 –1632 (3)
    For the first time, monolithic integration of a photodetector with a vertical-cavity surface emitting laser (VCSEL) is demonstrated. We have designed and fabricated VCSELs with monolithically integrated pin photodetectors which dynamically monitor (and can thus control) the output power of the lasers. The VCSELs lase at room temperature and emit a highly coherent, low-divergence, circular beam directly from the top surface. The integrated photodetector shows a linear response to the laser emission with an effective responsivity of 0.25 A/W.
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Monolithically integrated four-channel receiver array using diffused InGaAs JFET technology
  • Author(s): C. Mansfield ; D.J. Newson ; P. Birdsall ; J.A. Quayle ; R. Young ; M.D.A. MacBean ; R.P. Merrett
  • Source: Electronics Letters, Volume 27, Issue 18, p. 1632 –1633
  • DOI:  10.1049/el:19911020
  • Type: Article
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  • p. 1632 –1633 (2)
    Four-channel receiver arrays have been fabricated by monolithically integrating diffused InGaAs JFET-based electronics with InGaAs pin photodiodes. Cascode and simple inverter transimpedance amplifier circuits have been produced, both of which use a micro-FET as a tunable feedback element to vary bandwidth between 20 and 800 MHz. A sensitivity of –28.2dBm was achieved at 1.25Gbit/s with crosstalk between adjacent channels of –50dB (electrical).
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Segmental corrective training for hidden Markov model parameter estimation in speech recognition
Interleaved 5B20 code for insertion of carrier and clock pilots in 64-QAM systems
Microchannel plate image intensifier electron dynamics in magnetic field
Edge-based combination algorithm applied to multiple restored images
Ultralow specific on resistance UMOSFET with trench contacts for source and body regions realised by selfaligned process
  • Author(s): S. Matsumoto ; T. Ohno ; K. Izumi
  • Source: Electronics Letters, Volume 27, Issue 18, p. 1640 –1642
  • DOI:  10.1049/el:19911025
  • Type: Article
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  • p. 1640 –1642 (3)
    An ultralow on resistance power UMOSFET having a refined contact structure has been fabricated by a selfaligned process. The most important feature of this UMOSFET is its great increment of channel width per unit area, which leads to a noticeable reduction in the on resistance. A 50V UMOSFET with a specific on resistance of 0.58mΩcm2 has been achieved despite employing a relatively thick (520μm) substrate with a resistivity of 8mΩcm.
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Postdetection MRC diversity for π/4-shift QDPSK mobile radio
  • Author(s): F. Adachi  and  K. Ohno
  • Source: Electronics Letters, Volume 27, Issue 18, p. 1642 –1643
  • DOI:  10.1049/el:19911026
  • Type: Article
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  • p. 1642 –1643 (2)
    Diversity reception using a postdetection maximal-ratio combiner (MRC) was experimentally investigated for π/4-shift QDPSK signal transmission in Rayleigh fading environments. Two-branch postdetection MRC diversity reception provides a diversity gain, for a required Eb/N0, of about l.5dB over selection diversity. It is also effective in reducing the impact of multipath channel delay spread. The average BER due to delay spread can be further reduced by a factor of about 1-5 times from selection diversity.
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Fast method for accurate prediction of fibre laser oscillation wavelength
Teletext reception in mobile Rician fading channel with maximal ratio combining
Bit error probability for fading DPSK signals in microcellular land mobile radio systems
Selfsynchronisable binary Reed-Solomon code
Reflectometer calibration using load, short and offset shorts with unknown phase
Analysis of nonlinear circuits with distributed elements using PSPICE
Fibre-tip displacement sensor using sinusoidal FM-based technique
Control of optical fibre taper shape
Iddq secondary components in CMOS logic circuits preceded by defective stages affected by analogue type faults
  • Author(s): A. Rubio ; J. Figueras ; V. Champac ; R. Rodriguez ; J. Segura
  • Source: Electronics Letters, Volume 27, Issue 18, p. 1656 –1658
  • DOI:  10.1049/el:19911035
  • Type: Article
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  • p. 1656 –1658 (3)
    Certain physical failures produce abnormal voltages at the output of the defective stages. Iddq testing techniques are shown to be efficient in testing for these failures. Because of the intermediate analogue output of the faulty stage, posterior fault-free stages exhibit abnormal values of Iddq, increasing the effect of the fault. The set of stages influenced by the fault is modelled and analysed presenting characteristics of the propagation of the influence.
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Low coherence, interferometric fibre optic vibrometer using novel optical signal processing scheme
  • Author(s): K. Weir ; W.J.O. Boyle ; A.W. Palmer ; K.T.V. Grattan ; B.T. Meggitt
  • Source: Electronics Letters, Volume 27, Issue 18, p. 1658 –1660
  • DOI:  10.1049/el:19911036
  • Type: Article
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  • p. 1658 –1660 (3)
    Results are presented for the operation of a low coherence interferometric vibrometer using a fibre optic probe. A novel processing interferometer arrangement allows the absolute displacement of a vibrating surface to be reconstructed, and the use of a low coherence light source means unwanted spurious signals can be suppressed. A signal processing scheme to provide real time monitoring of the surface displacement is also possible.
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High-power (106 mW) CW operation of transverse-mode stabilised InGaAlP laser diodes with strained In0.62Ga0.38P active layer
  • Author(s): K. Nitta ; K. Itaya ; Y. Nishikawa ; M. Ishikawa ; M. Okajima ; G. Hatakoshi
  • Source: Electronics Letters, Volume 27, Issue 18, p. 1660 –1661
  • DOI:  10.1049/el:19911037
  • Type: Article
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  • p. 1660 –1661 (2)
    High-power CW operation of transverse-mode stabilised InGaAlP laser diodes has been achieved by using a selectively-buried-ridge waveguide structure with a very thin (150Å) active layer. A strained In0.622Ga0.38P active layer was adopted to obtain a sufficient bandgap difference between the active and cladding layers. A maximum light output of 106 mW was obtained from the laser with anti-reflection and high-reflection coatings.
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Observation of nonlinear interactions in 20 Gbit/s soliton transmission over 500 km using erbium-doped fibre amplifiers
  • Author(s): M. Nakazawa ; K. Suzuki ; E. Yamada ; H. Kubota
  • Source: Electronics Letters, Volume 27, Issue 18, p. 1662 –1663
  • DOI:  10.1049/el:19911038
  • Type: Article
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  • p. 1662 –1663 (2)
    The nonlinear pulling and pushing effects between adjacent solitons have been observed for the first time in a 20 Gbit/s soliton transmission system at around 400 km. Erbium-doped fibre amplifiers were used as lumped amplifiers for fibre loss compensation. The maximum transmission distance at which the interaction was negligible was about 350 km for a pulse width of 18ps and a repeater spacing of 25 km.
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Beam-propagation analysis of optical fibres by alternating direction implicit method
  • Author(s): J. Yamauchi ; T. Ando ; H. Nakano
  • Source: Electronics Letters, Volume 27, Issue 18, p. 1663 –1665
  • DOI:  10.1049/el:19911039
  • Type: Article
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  • p. 1663 –1665 (3)
    The alternating direction implicit (ADI) method is applied to the analysis of three-dimensional optical fibre waveguides. It is numerically demonstrated that the ADI method offers higher computational efficiency and a larger propagation step length, as compared with the conventional beam propagation method which uses fast Fourier transformation. The guided-mode transmission of coupled offset fibres is calculated using a transparent boundary condition.
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Periodically screened coplanar waveguides on semiconductors
Resonant tunnelling diode in MBE-grown delta-doped GaAs
  • Author(s): Y.H. Wang ; M.P. Houng ; H.H. Chen ; H.C. Wei
  • Source: Electronics Letters, Volume 27, Issue 18, p. 1667 –1668
  • DOI:  10.1049/el:19911041
  • Type: Article
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  • p. 1667 –1668 (2)
    A homotype negative differential resistance (NDR) device with GaAs delta-doped structure prepared by molecular beam epitaxy is demonstrated. Two Si and one Be delta-doped planes were inserted into the GaAs layer, i.e. n–∂n+–i–∂p+–i–∂n+–n, to form the required resonant tunnelling structures. Electrons are thus transported from the conduction band of the n+ layer and resonantly tunnel through the light hole level of the delta p+ induced quantum well. Symmetrical NDR characteristics with high peak to valley current ratios (PVR) of 3 operated at room temperature can be achieved comparable with those of the heterotype AIGaAs/GaAs double barrier structure. The PVR decreases with decreasing temperature are due to the inherent properties of the widening effect of the energy gap at low temperature. The calculated transmission coefficient using the two-band model with the transfer matrix method confirmed the observations.
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Optical equalisation with linearly tapered two-dissimilar-core fibre
Tunable SAW comb filter
Novel tunable GaAs MESFET OTA-C integrator suitable for high precision filtering applications
Constant-bandwidth current mode operational amplifier
  • Author(s): E. Bruun
  • Source: Electronics Letters, Volume 27, Issue 18, p. 1673 –1674
  • DOI:  10.1049/el:19911045
  • Type: Article
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  • p. 1673 –1674 (2)
    A current mode operational amplifier with a low impedance output for feedback connection is proposed and analysed theoretically. It is found to have a constant bandwidth independent of the gain in a closed loop configuration. This property is due to the loop gain independent of the closed loop gain. The amplifier is shown to be composed of a current conveyor input stage and another current conveyor output stage. Experimental results are presented to verify the constant bandwidth performance, and it is concluded that the proposed configuration is suitable for high frequency current mode amplifiers.
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Backward predictive block matching algorithm for low bit rate video coding
  • Author(s): S.-H. Jang  and  S.-D. Kim
  • Source: Electronics Letters, Volume 27, Issue 18, p. 1674 –1676
  • DOI:  10.1049/el:19911046
  • Type: Article
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  • p. 1674 –1676 (3)
    In contrast to the conventional block matching algorithm (BMA) in video coding, a backward predictive BMA which does not need the transmission of the motion vector is investigated. The motion vector is estimated using the previously estimated motion vectors and reconstructed pixels adjacent to a block to be coded. For application to low bit rate video coding, backward/forward adaptive BMA is devised. At 59kbit/s the proposed scheme provides 0.2–0.5dB improvement in peak signal to noise ratio (PSNR) over the conventional BMA.
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Very low threshold 1.5 μm GaInAs/AlGaInAs BH GRINSCH strained-layer quantum well laser diodes grown by MOCVD
  • Author(s): A. Kasukawa ; R. Bhat ; C. Caneau ; N. Andreadakis ; B. Pathak ; C.E. Zah ; M.A. Koza ; T.P. Lee
  • Source: Electronics Letters, Volume 27, Issue 18, p. 1676 –1678
  • DOI:  10.1049/el:19911047
  • Type: Article
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  • p. 1676 –1678 (3)
    A very low threshold current density of 400 A/cm2 was obtained in a 1.5 μm GaInAs/AlGaInAs compressive strained-layer quantum well laser diode, grown by metal organic chemical vapour deposition (MOCVD), with continuously graded-index separate-confinement-heterostructure. A very low threshold current of 3.6 mA was achieved in a high reflective coated 130μm long buried heterostructure laser diode with MOCVD grown semi-insulating current blocking layer. The lasing wavelength was 1.48 μm.
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High-speed analogue neural-network LSI employing super-selfaligned Si bipolar process technology
Ultrafast polarisation switching in ridge-waveguide laser diodes
  • Author(s): A. Klehr ; A. Bärwolff ; R. Müller ; M. Voβ ; J. Sacher ; W. Elsässer ; E.O. Göbel
  • Source: Electronics Letters, Volume 27, Issue 18, p. 1680 –1682
  • DOI:  10.1049/el:19911049
  • Type: Article
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  • p. 1680 –1682 (3)
    Time resolved polarisation characteristics of 1.3μm GaInAsP/InP-RW lasers are presented, showing the switching behaviour between the TE and TM mode as well as polarisation bistability. A switching time of about 50ps is observed for the transition between TE and TM polarisation under 900MHz current modulation. This is the shortest switching time measured so far.
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Compact dual-frequency feed for prime-focus paraboloid
  • Author(s): P.K. Trikha ; T.L. Landecker ; D. Routledge ; J.F. Vaneldik
  • Source: Electronics Letters, Volume 27, Issue 18, p. 1682 –1683
  • DOI:  10.1049/el:19911050
  • Type: Article
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  • p. 1682 –1683 (2)
    A compact dual-frequency feed operating at 1420 and 408MHz has been developed for a prime focus paraboloid. Efficient dual-mode performance at 1420MHz results from the combination of modes in a circular waveguide of diameter 0.91λ1420 and a surrounding cavity of diameter 2.611420. A single TE11 mode is excited in the larger cavity at 408MHz by four slots in its back wall, which acts as a dichroic structure, allowing the passage of 408MHz energy while reflecting 1420MHz fields. Satisfactory 408MHz performance is obtained in a feed of depth only 0.55λ408, without significant effect on 1420MHz performance.
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Simple approach for monolithic integration of DFB laser and passive waveguide

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