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Online ISSN 1350-911X Print ISSN 0013-5194

Electronics Letters

Volume 27, Issue 23, 7 November 1991

Volumes & issues:

Volume 27, Issue 23

7 November 1991

Coherent operation of 2-D monolithically integrated master oscillator power amplifier
  • Author(s): R. Parke ; D.F. Welch ; D. Mehuys
  • Source: Electronics Letters, Volume 27, Issue 23, p. 2097 –2098
  • DOI:  10.1049/el:19911299
  • Type: Article
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  • p. 2097 –2098 (2)
    Two dimensional monolithically integrated master oscillator power amplifiers (M-MOPAs) have been fabricated that emit in a single longitudinal mode to an output power of greater than 4.5 W. The spectral output is a single lontigudinal mode throughout the operating range and is identical to the output of the master oscillator. The far field radiation pattern transverse to the direction of propagation is characteristic of inphase diffraction limited operation at low output powers.
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Multigigabit per second subcarrier multiplexed optical fibre ring network
New EPL RLL(5,16) code
Switching speed of integrated acoustically-tunable optical filter
Low sidelobe arrays of parallel dipoles with finite reflector
Noncontact AE measurement system using acoustic microscope
  • Author(s): N. Chubachi  and  H. Kanai
  • Source: Electronics Letters, Volume 27, Issue 23, p. 2104 –2105
  • DOI:  10.1049/el:19911304
  • Type: Article
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  • p. 2104 –2105 (2)
    The surface of a slide glass (a specimen) with a notch was set in water at the focal region of a point-focus-beam (PFB) lens to detect the AE (acoustic emission) signals radiating from cracks around the notch during a three point bending test Output signals received by a transducer with a centre frequency around 50 MHz were amplified and A/D converted at a sampling rate of 200 MHz by a digital oscilloscope. The power spectra of the output signals were compared for the two cases with and without the weight used for the application of fracturing stress on the glass specimen. AE signals with a frequency range from a few megahertz to 100 MHz were successfully detected with this system for the glass specimen mounted on a small three point bending test bench.
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New message based priority buffer insertion ring protocol
Extension of method of lines to unbounded regions by using co-ordinate transformation
Novel frequency-selective twist polariser
Design of multivariable variable structure system for nonlinear time-varying systems using nonlinear switching surfaces
  • Author(s): J.-J. Lee
  • Source: Electronics Letters, Volume 27, Issue 23, p. 2111 –2113
  • DOI:  10.1049/el:19911308
  • Type: Article
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  • p. 2111 –2113 (3)
    Using nonlinear switching surfaces, a multivariable variable structure system (VSS) for nonlinear time-varying systems in the presence of disturbances and parameter variations is proposed. In the previous sliding mode control, the switching surfaces are linear functions and therefore the speed of response is relatively low. To overcome this problem, the proposed method improves the speed of response and good transient response is thus obtained. An example has shown its effectiveness in controlling the nonlinear time-varying systems.
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Selective photochemical dry etching of GaAs/AlGaAs and InGaAs/InAlAs heterostructures
Experimental comparison of base recombination currents in abrupt and graded AlGaAs/GaAs heterojunction bipolar transistors
  • Author(s): W. Liu
  • Source: Electronics Letters, Volume 27, Issue 23, p. 2115 –2116
  • DOI:  10.1049/el:19911310
  • Type: Article
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  • p. 2115 –2116 (2)
    The relative importance of the base bulk recombination current and the base-emitter junction space charge recombination current is examined for AlGaAs/GaAs HBTs with different grading schemes in the base-emitter junction. Experimental results demonstrate that, in abrupt HBTs, the base bulk recombination current is larger, and the base current increases with the base-emitter bias with an ideality factor of ∼1. In contrast, in graded HBTs, the space charge recombination current dominates and the base current ideality factor is ∼2. These experimental results agree well with a published theoretical calculation.
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35 GHz integrated circuit rectifying antenna with 33% efficiency
Widely tunable narrow linewidth erbium doped fibre ring laser
Explicit finite difference vectorial beam propagation method
Ka-band monolithic amplifier using 0.5 μm gate length ion-implanted GaAs/AlGaAs heterojunction FET technology
  • Author(s): T. Hwang ; M. Feng ; C.L. Lau
  • Source: Electronics Letters, Volume 27, Issue 23, p. 2121 –2122
  • DOI:  10.1049/el:19911314
  • Type: Article
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  • p. 2121 –2122 (2)
    Monolithic, two-stage amplifiers using 0.5×80 μm2 gate GaAs/AlGaAs heterojunction FETs have been developed for Ka-band operation. These monolithic two-stage amplifiers were fabricated using ion implantation for the active layer and optical lithography for the 0.5 μm gate length. MMIC two-stage amplifiers achieved average gains of 12.6±1.4 dB at 30GHz and 8.8±2.0 dB at 40GHz, respectively, for all 39 sites across a 3 inch diameter wafer. These are the first reported results the MMIC two-stage amplifiers using 0.5μm gate length ion-implanted GaAs/AlGaAs heterojunction FETs achieved over 10 dB gain at Ka band.
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Push-pull current circuit for biasing CMOS amplifiers with rail-to-rail input common-mode range
  • Author(s): J.F. Duque-Carrillo ; R. Pérez-Aloe ; A. Morillo
  • Source: Electronics Letters, Volume 27, Issue 23, p. 2122 –2125
  • DOI:  10.1049/el:19911315
  • Type: Article
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  • p. 2122 –2125 (4)
    A push-pull current circuit for biasing CMOS amplifiers with rail-to-rail input common-mode range is presented. By means of a feedback action, the circuit avoids the large magnitude deviations inherent to this type of amplifier and thus facilitates their optimisation and compensation. Simulated and experimental results obtained from a fabricated 2 μm CMOS test chip are reported.
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High quantum efficiency, long wavelength InP/InGaAs microcavity photodiode
  • Author(s): A.G. Dentai ; R. Kuchibhotla ; J.C. Campbell ; C. Tsai ; C. Lei
  • Source: Electronics Letters, Volume 27, Issue 23, p. 2125 –2127
  • DOI:  10.1049/el:19911316
  • Type: Article
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  • p. 2125 –2127 (3)
    There is an inherent tradeoff between the quantum efficiency and bandwidth of conventional pin photodiodes. In the case of devices based on III-V semiconductors, an absorption region thickness of approximately 2 μm is required to achieve quantum efficiencies greater than 80%, although this limits the transit-time-limited bandwidth to less than 15 GHz. It has recently been shown that a microcavity photodiode can circumvent this performance tradeoff and achieve both high quantum efficiency and large bandwidths. The fabrication of a microcavity pin photodiode with a high quantum efficiency near 1.55 μm is described. An external quantum efficiency of 82% at 1480 nm has been achieved with an InGaAs absorption layer only 2000 Å thick embedded in a resonant cavity grown by metal organic vapour phase epitaxy (MOVPE).
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Simulation of CDMA system performance with feedback power control
  • Author(s): S. Ariyavisitakul  and  L.F. Chang
  • Source: Electronics Letters, Volume 27, Issue 23, p. 2127 –2128
  • DOI:  10.1049/el:19911317
  • Type: Article
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  • p. 2127 –2128 (2)
    The Letter presents a summary of the results of a study on CDMA feedback power control in multipath fading radio channels. The signal and interference statistics after power control are presented for a simulated radio system which includes multiple base stations. It is shown that often used analyses based on perfect average power control lead to optimistic capacity results because interference is underestimated by 1-2 dB.
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Planar broadband image rejection mixer
Specialised attack on Chor-Rivest public key cryptosystem
Design and fabrication of silica-based integrated-optic 1×128 power splitter
Impact of local oscillator intensity noise on performance of coherent subcarrier multiplexing system using common local oscillator (CLO)
  • Author(s): Y.-H. Lee  and  H.-W. Tsao
  • Source: Electronics Letters, Volume 27, Issue 23, p. 2133 –2135
  • DOI:  10.1049/el:19911321
  • Type: Article
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  • p. 2133 –2135 (3)
    The impact of local oscillator intensity noise on the performance of a coherent subcarrier multiplexing (CSCM) system using a common local oscillator (CLO) is analysed. For a given LO power, RIN noise, and thermal noise, the CNR can be expressed in terms of x, the ratio of σsh2 + σth2 over σRIN2 and, for x ≪1, the CNR decreases as LO power increases; for x ≫ 1, the CNR increases as the LO power increases; as x approaches 1, there exist an optimum value of local oscillator power and a corresponding maximum CNR. For a system with RIN = –150dB/Hz, Ps = –20dBm, β = 0.02, N = 40, NF = 3dB and B = 10MHz, the (PLO)opt is found to be –4dBm and {CNR)max 22.5dB.
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Delineation of junctions using Secco and periodic etches
  • Author(s): J.C. Carter  and  A.G.R. Evans
  • Source: Electronics Letters, Volume 27, Issue 23, p. 2135 –2136
  • DOI:  10.1049/el:19911322
  • Type: Article
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  • p. 2135 –2136 (2)
    Secco and periodic etches have been used to delineate n+p and p+n junctions found in ULSI CMOS. Preliminary trials indicated that delineated depth depends on etch time. An interpretation of these results in terms of etching of the substrate material leads to a simple expression between delineated depth and etch time. Once this relation has been established the technique allows a quick and consistent check on two dimensional dopant profiles and has been used on shallow junctions found in deep submicrometre structures.
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New reflective type star couplers for full duplex channels
Novel structure MQW electroabsorption modulator/DFB-laser integrated device fabricated by selective area MOCVD growth
Using quadratic residue arithmetic for computing skew cyclic convolutions
Complementary vertical bipolar transistor process using high-energy ion implantation
  • Author(s): F.W. Ragay ; A.A.I. Aarnink ; H. Wallinga
  • Source: Electronics Letters, Volume 27, Issue 23, p. 2141 –2143
  • DOI:  10.1049/el:19911326
  • Type: Article
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  • p. 2141 –2143 (3)
    High-energy ion implantation is used as a key processing step in the formation of a complementary bipolar process with both transistor types being vertical. Both npn and pnp transistors are made vertically with a deep implanted collector region. Combinations of epitaxial and buried layers are avoided. Both transistors have an ideal Gummel plot with a current gain of about 60. Cutoff frequencies of over 1 GHz have been measured, which is much higher than for conventional lateral pnp transistors.
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Er3+-doped multicomponent glass core fibre amplifier pumped at 1.48 μm
Correlation model for shadow fading in mobile radio systems
Four-quadrant multiplier combining sigma-delta and multirate processing techniques
  • Author(s): J. Grilo  and  J.E. Franca
  • Source: Electronics Letters, Volume 27, Issue 23, p. 2146 –2148
  • DOI:  10.1049/el:19911329
  • Type: Article
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  • p. 2146 –2148 (3)
    A mixed analogue-digital solution combining sigma-delta and multirate processing techniques is proposed for realising four-quadrant multipliers. This overcomes the major limitations of purely analogue circuits and still achieves the attractive benefits of low power consumption and small chip size which cannot be afforded using digital signal processing techniques together with auxiliary analogue-digital and digital-analogue convertors.
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Singlemode diode-pumped tunable erbium-doped fibre laser with linewidth less than 5.5 kHz
  • Author(s): J.L. Zyskind ; J.W. Sulhoff ; Y. Sun ; J. Stone ; L.W. Stulz ; G.T. Harvey ; D.J. Digiovanni ; H.M. Presby ; A. Piccirilli ; U. Koren ; R.M. Jopson
  • Source: Electronics Letters, Volume 27, Issue 23, p. 2148 –2149
  • DOI:  10.1049/el:19911330
  • Type: Article
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  • p. 2148 –2149 (2)
    A diode-pumped, broadly tunable, single frequency erbium-doped fibre ring laser is reported. Tuning and single longitudinal mode selection are accomplished by use of two fibre Fabry-Perot etalons. The threshold for 1.48 μm pumping is 8.8 mW and the slope efficiency is 11.5%. The laser can be tuned to wavelengths between 1.530 and 1.575 μm and operates singlemode throughout this range. Its linewidth is measured at 1.56 μm to be less than 5.5 kHz.
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Fast tracking RLS algorithm using novel variable forgetting factor with unity zone
Improving design feedback equaliser performance using neural networks
  • Author(s): K. Raivio ; O. Simula ; J. Henriksson
  • Source: Electronics Letters, Volume 27, Issue 23, p. 2151 –2153
  • DOI:  10.1049/el:19911332
  • Type: Article
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  • p. 2151 –2153 (3)
    Novel equaliser structures combining traditional transversal equalisers and neural computation have been introduced for adaptive discrete-signal detection. Extensive simulations using a two-path channel model and 16QAM modulation have been run to investigate the performance characteristics of these neural equalisers. The results have shown that they adapt very well to changing channel conditions, including both linear multipath and nonlinear distortions. The new structures are superior when compared to the traditional equalisers with equal computational complexity, especially in difficult channels.
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High sensitivity fibre preamplifier receiver for multichannel applications
Automatic optical-loss compensation with Er-doped fibre amplifier
Efficient design of shaped reflectors using successive projections
Noise model for double barrier resonant tunnel diodes
IGBT convertor with active snubber for soft switching
High-speed and low-driving-voltage InGaAs/InAlAs multiquantum well optical modulators
  • Author(s): I. Kotaka ; K. Wakita ; K. Kawano ; M. Asai ; M. Naganuma
  • Source: Electronics Letters, Volume 27, Issue 23, p. 2162 –2163
  • DOI:  10.1049/el:19911338
  • Type: Article
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  • p. 2162 –2163 (2)
    A study is made of high-speed, large-signal intensity modulation (in the frequency bandwidth of 16 GHz) with a low driving voltage of 2.0 V and a 20 dB extinction ratio. The modulator successfully operates at a long wavelength 1.55 μm with a low insertion loss of 6 dB. The 100 μm long device with 16 GHz bandwidth and 1.5 V 10 dB on/off ratio voltage results in a bandwidth to voltage ratio of 11 GHz/V, which is the highest yet reported for an external intensity modulator.
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Explicit expression for Brewster angles of isotropic–bi-isotropic interface
  • Author(s): I.V. Lindell ; A.H. Sihvola ; A.J. Viitanen
  • Source: Electronics Letters, Volume 27, Issue 23, p. 2163 –2165
  • DOI:  10.1049/el:19911339
  • Type: Article
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  • p. 2163 –2165 (3)
    An explicit expression giving the two Brewster angles for the interface between isotropic and bi-isotropic (nonreciprocal chiral) media is presented. These angles correspond to two eigenpolarisations for which the reflection of a plane wave is zero at the interface. The result contains as a special case an expression for the Brewster angles of the chiral interface, which appears not to have been found earlier in closed form. A qualitatively new effect when compared to the isotropic problem is the appearance of two real Brewster angles for certain bi-isotropic media. This effect is seen to prevail only with nonzero chirality of the medium.
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Performance of Manhattan street network (MSN) architecture under zonal traffic distribution (ZTD) patterns
Silver-film ion-exchanged singlemode waveguides in Er doped phosphate glass
Rain attenuation statistics on 30 GHz terrestrial link
Selfconfiguring optical fibre-tap/photodetector modulator with very high photodetection efficiency and high extinction ratio
Current conveyor based EMG amplifier with shutdown control
  • Author(s): E. Bruun  and  E.-U. Haxthausen
  • Source: Electronics Letters, Volume 27, Issue 23, p. 2172 –2174
  • DOI:  10.1049/el:19911344
  • Type: Article
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  • p. 2172 –2174 (3)
    A current conveyor implementation of an EMG amplifier with shutdown control is described. The shutdown control allows for measurements on electrically stimulated muscles because the amplifier can be turned off during the stimulation. The implementation using current conveyors makes it possible to perform the shutdown switching at a low impedance node, reducing switching transients to a level which does not cause saturation of the EMG amplifier. Experimental results indicate that the recovery period, required in a traditional EMG amplifier after the stimulation pulse, has been eliminated. The conveyor based amplifier is able to measure the EMG signals accurately immediately after the stimulation pulse.
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Highly integrated ATM/SONET user-network interface
  • Author(s): G.R. Lalk ; L. Gluck ; T.C. Banwell ; C.A. Johnston ; T.J. Robe ; K.A. Walsh ; K.C. Young
  • Source: Electronics Letters, Volume 27, Issue 23, p. 2174 –2176
  • DOI:  10.1049/el:19911345
  • Type: Article
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  • p. 2174 –2176 (3)
    The implementation of a highly integrated experimental research prototype ATM/SONET interface that operates at the SONET OC-3 rate of 155.52 Mbit/s is reported. The prototype interface provides various features of the physical (SONET) and asynchronous transfer mode (ATM) layers of the B-ISDN protocol reference model. This type of interface could be used in applications such as workstation interfaces in a switched ATM local area network or for the user-network interface in a broadband public network or customer premises network.
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Reduction of spatial hole burning by single phase modulator in linear Nd3+ fibre laser
Optical QPSK transmission system with novel digital receiver concept
High performance 10Gbit/s optical transmission system using erbium-doped fibre preamplifier
Crystalline pMOS inverter using amorphous thin film transistor as active load
  • Author(s): H.-C. Lin ; W.-J. Sah ; S.-C. Lee
  • Source: Electronics Letters, Volume 27, Issue 23, p. 2180 –2181
  • DOI:  10.1049/el:19911349
  • Type: Article
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  • p. 2180 –2181 (2)
    The integration of the amorphous silicon (a-Si:H) thin film transistor on top of a crystalline p-type silicon metal–oxide–semiconductor (pMOS) transistor to serve as active load has been achieved successfully. The vertical integration of crystalline silicon and amorphous silicon circuits to form the three dimensional structure is a promising technique for future application in high density memory cells and neural network image sensors.
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New performance function and variable step size LMS algorithm derived by Karni and Zeng
  • Author(s): D.J. Park
  • Source: Electronics Letters, Volume 27, Issue 23, p. 2182 –2183
  • DOI:  10.1049/el:19911350
  • Type: Article
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  • p. 2182 –2183 (2)
    The variable step size LMS algorithm (Karni-Zeng) can be derived from a new performance function which has an additional exponential term to that of the conventional LMS algorithm. Its fast convergence and low misadjustment error properties can be interpreted and analysed through the new performance function. The algorithm uses a large step size when the gradient on the surface of the performance function is large and a small step size when the gradient is small.
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1.5 Gbit/s transmission system using all optical wavelength convertor based on tunable two-electrode DFB laser
Dielectric-loaded elliptical waveguide
AuBe ohmic contacts to p-InGaAlAs formed by rapid thermal annealing
  • Author(s): T.C. Shen ; J. Reed ; Z.F. Fan ; G.B. Gao ; H. Morkoç
  • Source: Electronics Letters, Volume 27, Issue 23, p. 2187 –2189
  • DOI:  10.1049/el:19911353
  • Type: Article
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  • p. 2187 –2189 (3)
    AuBe ohmic contacts to p-In0.33Ga0.35Al0.12As (Be: 5 × 1018cm-3) formed by rapid thermal annealing (RTA) have been studied and compared with those formed by conventional alloying. Using thermally evaporated AuBe, specific contact resistances in the low μΩ. cm2 range have been achieved by both methods. However, contacts made by RTA demonstrated good thermal stability whereas the contacts by conventional alloying degraded more than one order of magnitude at 250°C for 100h.
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High-efficiency Ku-band HBT amplifier with 1 W CW output power
  • Author(s): P. Bartusiak ; T. Henderson ; T. Kim ; A. Khatibzadeh ; B. Bayraktaroglu
  • Source: Electronics Letters, Volume 27, Issue 23, p. 2189 –2190
  • DOI:  10.1049/el:19911354
  • Type: Article
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  • p. 2189 –2190 (2)
    A compact, high-voltage AlGaAs/GaAs HBT was developed for applications in the Ku band using carbon-doped base structures. A single unit-cell device, operating under common-emitter mode and 10 V collector bias, produced 1.0 W CW output power at 15 GHz with 5.0 dB gain and 42% power-added efficiency. The power density of the device was a record 5.6 W/mm of emitter length.
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Novel photonic device using nonlinear corner-bend structure
Tunnel diode with asymmetric spacer layers for use as microwave detector
  • Author(s): R.T. Syme ; M.J. Kelly ; R.S. Smith ; A. Condie ; I. Dale
  • Source: Electronics Letters, Volume 27, Issue 23, p. 2192 –2194
  • DOI:  10.1049/el:19911356
  • Type: Article
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  • p. 2192 –2194 (3)
    A novel single-barrier, intraband tunnel diodes with asymmetric spacer layers has been designed and fabricated. The structural asymmetry leads to asymmetric current-voltage characteristics and makes the diodes suitable for use as zero-bias microwave detectors. The voltage sensitivity as 9.375 GHz shows a weak temperature dependence (typically less than 1 dB variation over − 40° –+ 80°C, compared with 3 dB for a zero-bias Schottky diode). The maximum microwave power handling is also superior to a germanium back diode (1 dB rolloff typically at + 10 dBm compared with –10 dBm for the Ge back diode) and similar to a zero-bias Schottky diode.
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Differential measurement technique for optical fibre sensors
Measurement method of pn junction depth using light spectrum response
Erratum: Evaluation of chromatic dispersion in erbium doped fibre amplifiers
Erratum: Measurement of pump induced refractive index change in an erbium doped fibre amplifier

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