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Online ISSN 1350-911X Print ISSN 0013-5194

Electronics Letters

Volume 29, Issue 1, 7 January 1993

Volumes & issues:

Volume 29, Issue 1

7 January 1993

Low threshold 0.98 μm aluminium-free strained-quantum-well InGaAs/InGaAsP/InGaP lasers
  • Author(s): C.J. Chang-Hasnain ; R. Bhat ; H. Leblanc ; M.A. Koza
  • Source: Electronics Letters, Volume 29, Issue 1, p. 1 –2
  • DOI:  10.1049/el:19930001
  • Type: Article
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  • p. 1 –2 (2)
    Aluminium-free strained-quantum-well In0.2Ga0.8As lasers employing novel two-stepped InGaAsP confinement layers and InGaP cladding layers on a GaAs substrate are demonstrated for the first time. Threshold current density as low as 58 A/cm2 is obtained with broad stripe lasers. This threshold current density is, to the authors' knowledge, the lowest reported for 0.98 μm lasers grown by organic chemical vapour deposition.
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Design of impedance-transforming microstrip-balanced stripline tapered transitions
  • Author(s): J. Chramiec  and  B.J. Janiczak
  • Source: Electronics Letters, Volume 29, Issue 1, p. 3 –4
  • DOI:  10.1049/el:19930002
  • Type: Article
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  • p. 3 –4 (2)
    An improved approach to the computer-aided modelling of impedance-transforming microstrip-balanced stripline tapers used in microwave doubly balanced mixers is presented. The spectral domain method has been used to determine the parameters of a suspended microstrip with finite ground plane width. Calculations show that dispersion effects in the analysed structure are insignificant. The designed and realised 50–100ω transition on a 1.5mm thick alumina substrate exhibited very good or acceptable performance up to 10 and 15GHz, respectively. A method to suppress undesired modes appearing in the case of shielded transitions has been proposed and experimentally verified.
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Chromatic dispersion measurements of 4564 km optical amplifier repeater system
Design of hardware efficient selftimed circuits
  • Author(s): S.-L. Lu
  • Source: Electronics Letters, Volume 29, Issue 1, p. 6 –7
  • DOI:  10.1049/el:19930004
  • Type: Article
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  • p. 6 –7 (2)
    One objection to selftimed circuits has been the overhead of hardware required to implement the control circuitry. In the Letter an alternative approach to the implementation of selftimed circuit elements is proposed. By using an alternative CMOS logic family, the enable/disable CMOS differential logic (ECDL), instead of the dynamic cascoded voltage switch logic (DCVSL) to build selftimed blocks, the amount of overhead is reduced. Moreover, because ECDL is static, there is no minimum timing constraint to satisfy in comparison with selftimed systems that use DCVSL. An example of a first-in first-out (FIFO) memory is used to illustrate the technique.
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Self-checking sequential circuit design using m-out-of-n codes
  • Author(s): F.Y. Busaba  and  P.K. Lala
  • Source: Electronics Letters, Volume 29, Issue 1, p. 7 –9
  • DOI:  10.1049/el:19930005
  • Type: Article
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  • p. 7 –9 (3)
    A technique for designing sequential circuits which are totally self-checking for single stuck at faults is presented. This technique uses m-out-of-n codes for state assignments and for output encoding. The next stage logic and the output logic are implemented such that any stuck-at fault will either create a single bit error or unidirectional multibit error at the output. The technique has been applied to MCNC benchmark circuits and the overhead is estimated.
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14 GHz bandwidth MSM photodiode AlGaAs/GaAs HEMT monolithic integrated optoelectronic receiver
  • Author(s): V. Hurm ; M. Ludwig ; J. Rosenzweig ; W. Benz ; M. Berroth ; R. Bosch ; W. Bronner ; A. Hülsmann ; K. Köhler ; B. Raynor ; J. Schneider
  • Source: Electronics Letters, Volume 29, Issue 1, p. 9 –10
  • DOI:  10.1049/el:19930006
  • Type: Article
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  • p. 9 –10 (2)
    A monolithic optoelectronic receiver consisting of an MSM photodiode and a two-stage amplifier has been fabricated using an enhancement/depletion 0.3 μm recessed-gate AIGaAs/GaAs HEMT process. The bandwidth of 14.3 GHz implies suitability for transmission rates of up to 20 Gbit/s. The transimpedance is 670 Ω (into 50 Ω) and the projected sensitivity is −16.4 dBm (BER = 10−9).
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Super low noise pseudomorphic InGaAs channel InP HEMTs
  • Author(s): T. Hwang ; P. Chye ; P. Gregory
  • Source: Electronics Letters, Volume 29, Issue 1, p. 10 –11
  • DOI:  10.1049/el:19930007
  • Type: Article
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  • p. 10 –11 (2)
    0.15 μm gate length pseudomorphic InGaAs channel InP-based HEMTs developed in our laboratory have exhibited super low noise and high associated gain performance at 12GHz. The use of a highly doped InGaAs cap layer associated with optimal thickness of the Schottky barrier layer leads to excellent gate characteristics and noise figure improvement. The new pseudomorphic HEMTs with a 0.15 μm long and 150 μm wide gate geometry showed a noise figure of 0.23dB with 16dB associated gain at 12GHz.
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Soliton spectral tunnelling effect
Measured properties of aluminium nitride microstrip substrates
Polarisation-dependent site-shielding factor of block-shaped obstacle
  • Author(s): G.A.J. van Dooren  and  M.H.A.J. Herben
  • Source: Electronics Letters, Volume 29, Issue 1, p. 15 –16
  • DOI:  10.1049/el:19930010
  • Type: Article
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  • p. 15 –16 (2)
    A comparison between the measured and theoretically predicted site-shielding factor (SSF) of an obstacle resembling a building is made. The SSF, which expresses the additional attenuation caused by an obstacle on the propagation path, is measured along a cylindrical arc behind the obstacle at a frequency of 50 GHz. The theoretical model uses the uniform geometrical theory of diffraction (UTD) including corner, edge-to-edge, and edge-to-corner diffraction. The agreement between the measured and theoretically derived results is excellent. The strong polarisation dependence of the SSF encountered appears to be due to slope diffraction.
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Resonance properties of omnidirectional slot doublet in rectangular waveguide
Reactive ion etching of β-SiC in CCl2F2/O2
  • Author(s): J. Kuzmik ; C. Michelakis ; G. Konstantinidis ; N. Papanicolaou
  • Source: Electronics Letters, Volume 29, Issue 1, p. 18 –19
  • DOI:  10.1049/el:19930012
  • Type: Article
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  • p. 18 –19 (2)
    For the first time, the reactive ion etching (RIE) of β-SiC in CCI2F2/O2 gas mixture is reported. The addition of oxygen to the CC12F2 does not appear to enhance the etch rate, however, the RF power and the DC bias conditions prove to be the dominant factors for controlling the etch rate. In addition, fine line structures with vertical walls and smooth etched surfaces are achieved.
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Generating RSA keys without the Euclid algorithm
  • Author(s): M.F.A. Derôme
  • Source: Electronics Letters, Volume 29, Issue 1, p. 19 –21
  • DOI:  10.1049/el:19930013
  • Type: Article
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  • p. 19 –21 (3)
    A simple formula is derived giving e−1 mod s, in terms of modular addition, multiplication, and exponentiation operations, for any positive integer s not containing the prime factor e. These modular operations would be part of the instruction set of any hardware implementation of the RSA public key algorithm, making it particularly convenient for calculating RSA key pairs where one of the pair is a prime. The formula is extended to nonprime inverses.
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Polarisation independent refractive index change in InGaAs/InGaAsP tensile strained quantum well
  • Author(s): T. Aizawa ; K.G. Ravikumar ; R. Yamauchi
  • Source: Electronics Letters, Volume 29, Issue 1, p. 21 –22
  • DOI:  10.1049/el:19930014
  • Type: Article
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  • p. 21 –22 (2)
    The polarisation independent refractive index change in the tensile strained InGaAs/InGaAsP quantum well (QW) structure has been measured over the whole spectral range, i.e. near and below the bandgap energy. By inducing a 0.3% tensile strain in the InGaAs QW, the spectral profiles for the TE and TM modes are brought closer to each other, with the same refractive index change occurring at around 1.565 μm.
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Passive analysis technique for packet link performance
High-temperature operation of 637 nm AlGaInP MQW laser diodes with quaternary QWs grown on misoriented substrates
Application of micro-airbridge isolation in high speed HBT fabrication
  • Author(s): S. Tadayon ; G. Metze ; A. Cornfeld ; K. Pande ; H. Huang ; B. Tadayon
  • Source: Electronics Letters, Volume 29, Issue 1, p. 26 –27
  • DOI:  10.1049/el:19930017
  • Type: Article
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  • p. 26 –27 (2)
    A new selfaligned AlGaAs/GaAs heterojunction bipolar transistor (HBT) fabrication process is presented, featuring a deep wet etching that undercuts the base and the emitter interconnects, and forms micro-airbridges for device isolation. The advantages of this isolation process include critical lithographies on flat surfaces, capacitance reduction, and compatibility with thick collector layers. 1.5 × 10 μm2 HBT devices, grown by MOCVD, exhibit an Fmax of 120 GHz.
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High reflectivity and narrow bandwidth fibre gratings written by single excimer pulse
Modal interference in all-fibre sensor measured by coherence multiplexing technique
Novel acoustically tuned fibre laser
Polarisation mode dispersion measurements in 4564 km EDFA system
  • Author(s): Y. Namihira ; T. Kawazawa ; H. Wakabayashi
  • Source: Electronics Letters, Volume 29, Issue 1, p. 32 –33
  • DOI:  10.1049/el:19930021
  • Type: Article
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  • p. 32 –33 (2)
    Polarisation mode dispersion (PMD) measurements in 4564 km of dispersion shifted fibre (DSF) with 138 cascaded Er-doped fibre amplifiers (EDFAs) are presented for the first time. The PMD in the 4564 km EDFA system was measured to be ~16 ps. Square-root dependency with length of 0.20–0.30 ps/√(km) in a 4564 km EDFA system is also demonstrated. The PMD value from 20 to 30 ps is estimated for a 10000 km transoceanic optical amplifier repeater system.
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Electrical properties of Si-implanted gate oxides
  • Author(s): J. Kim ; A.B. Joshi ; G.Q. Lo ; D.L. Kwong ; S. Lee
  • Source: Electronics Letters, Volume 29, Issue 1, p. 34 –35
  • DOI:  10.1049/el:19930022
  • Type: Article
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  • p. 34 –35 (2)
    The electrical properties of MOS capacitors with Si-implanted SiO2 are investigated. It is demonstrated that a hysteresis effect is present in the capacitance-voltage characteristics of MOS capacitors with Si-implanted gate oxide. Both fixed charge and interface state density are observed to increase with Si-implant dose. The current conduction in these oxide films was also examined.
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Comment: Polynomial representation of spectral coefficients
Measurements of two-photon absorption coefficient and induced nonlinear refractive-index in GaAs/AlGaAs multiquantum well waveguides
Circuit performance of low temperature CMOS polysilicon TFT operational amplifiers
Cryptanalysis of tree-structured substitution-permutation networks
Fast tunable 1.5 μm distributed Bragg reflector laser for optical switching applications
Influence of optical amplifier location on four-wave mixing induced crosstalk
Broadband uniplanar hybrid ring coupler
  • Author(s): C.-H. Ho ; L. Fan ; K. Chang
  • Source: Electronics Letters, Volume 29, Issue 1, p. 44 –45
  • DOI:  10.1049/el:19930029
  • Type: Article
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  • p. 44 –45 (2)
    A new uniplanar hybrid ring coupler using coplanar waveguide (CPW) and slotline is presented. This new coupler provides substantially improved amplitude and phase characteristics over a broad bandwidth compared with the conventional microstrip hybrid ring couplers. Experimental results show that the new coupler has a bandwidth of approximately one octave from 2 to 4 GHz with ±0.25 dB power dividing balance and ±1° phase balance.
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Enhanced UV photosensitivity in boron codoped germanosilicate fibres
Spectral characterisation of photoinduced high efficient Bragg gratings in standard telecommunication fibres
  • Author(s): H.G. Limberger ; P.Y. Fonjallaz ; R.P. Salathé
  • Source: Electronics Letters, Volume 29, Issue 1, p. 47 –49
  • DOI:  10.1049/el:19930031
  • Type: Article
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  • p. 47 –49 (3)
    High efficiency Bragg gratings were obtained in a standard telecommunication fibre with a germanium concentration of 3%. The best filter has a reflectivity of 94% and a bandwidth of 1.7nm. Its symmetric reflection spectrum with three side-lobes is in very good agreement with a theoretical calculation. A refractive index change of 1.2 × 10−3 and a length of 0.84mm were obtained by fitting a theoretical filter curve to the experiment data. Additionally, the transmission spectrum shows, on the short wavelength side of the resonance, a region with a maximum of 19% loss.
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Demonstration of over 100 million round trips in recirculating fibre loop with all-optical regeneration
Chirp and feedback control in semiconductor pigtailed DFB lasers without integrated isolator
High power ytterbium (Yb3+)-doped fibre laser operating in the 1.12 μm region
Annealed twists for stable tuned fused polished couplers
Nearly transform-limited pulse (3.6 ps) generation from gain-switched 1.55 μm distributed feedback laser by using fibre compression technique
Applying the Marx bank circuit configuration to power MOSFETs
Influence of resistances on characteristics of vertically integrated resonant tunnelling diodes
Evaluation of particle relaxation times for device simulation of submicrometre GaAs devices using ensemble Monte-Carlo simulation
Monolithic integration of lasers with FET and bipolar transistors in inversion channel technology
  • Author(s): P.A. Evaldsson ; T.A. Vang ; G.W. Taylor ; S.K. Sargood ; P.A. Kiely ; P. Cook
  • Source: Electronics Letters, Volume 29, Issue 1, p. 60 –62
  • DOI:  10.1049/el:19930040
  • Type: Article
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  • p. 60 –62 (3)
    The first monolithic integration of lasers with HFETs and bipolar transistors in inversion channel technology is presented. A threshold current of 2mA and a slope efficiency of 8mW/mA was obtained for the bipolar/laser circuit. The transfer characteristic for the integrated HFET/laser converts voltage to output power. The output efficiency for this circuit was 2mW/V, where the voltage was divided across the laser and the HFET.
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Performance of dilated banyan network with recirculation
Generation of 98 fs optical pulses directly from an erbium-doped fibre ring laser at 1.57 μm
  • Author(s): M. Nakazawa ; E. Yoshida ; Y. Kimura
  • Source: Electronics Letters, Volume 29, Issue 1, p. 63 –65
  • DOI:  10.1049/el:19930042
  • Type: Article
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  • p. 63 –65 (3)
    Optical pulses as short as 98 fs at 1.57 μm have been successfully generated for the first time directly from a laserdiode pumped erbium-doped fibre laser with a nonlinear amplifying loop mirror. By using a low GVD polarisation sensitive isolator and reducing the fibre length in a nonlinear loop, 124 fs pulses were obtained. They were further shortened to 98 fs by installing an EDFA as an active pulse compressor and a positive GVD fibre for chirp compensation.
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Modified Moose estimator with plant-filter mismatch compensation
  • Author(s): C.H. Lim  and  H.S. Lee
  • Source: Electronics Letters, Volume 29, Issue 1, p. 65 –67
  • DOI:  10.1049/el:19930043
  • Type: Article
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  • p. 65 –67 (3)
    The original Moose estimator suffers from large performance degradation when there is plant-filter mismatch. To alleviate this, we propose a Moose estimator which compensates for plant-filter mismatch, and show by the Monte-Carlo simulation that the proposed estimator performs much better than the original Moose estimator in the case of plant-filter mismatch, especially when the sampling interval is relatively small.
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BiCMOS dynamic defuzzifying circuit for fuzzy logic controllers
  • Author(s): J.B. Kuo ; H.J. Huang ; S.S. Chen ; C.S. Chiang
  • Source: Electronics Letters, Volume 29, Issue 1, p. 67 –68
  • DOI:  10.1049/el:19930044
  • Type: Article
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  • p. 67 –68 (2)
    A BiCMOS dynamic defuzzifying circuit is presented which uses BiCMOS dynamic summation and divider circuits for realising fuzzy logic controllers. Using BiCMOS dynamic circuits, a defuzzifying circuit, designed based on a 2 μm BiCMOS technology, shows a 1.6μs conversion time for converting 64 input fuzzy words into a deterministic value, which is a ×2 improvement in speed as compared with the CMOS circuit.
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Phase sensitive investigations of 3×3 singlemode fibre directional couplers
ML phase estimation for π/4-QPSK modulated signals
Prediction of rain attenuation in slant paths in equatorial areas: application of two layer rain model
  • Author(s): E. Matricciani
  • Source: Electronics Letters, Volume 29, Issue 1, p. 72 –73
  • DOI:  10.1049/el:19930047
  • Type: Article
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  • p. 72 –73 (2)
    The Letter reports the performance of the two layer rain model at three equatorial sites in Brazil (Belem, Manaus and Rio), for which (relatively) long term (two years for each experiment) attenuation at 12GHz and concurrent rain rate distributions have become recently available in the CCIR data bank of slant path attenuation. The prediction is excellent for Belem and Manaus, and good for Rio. The results may suggest that the CCIR rain height at latitudes around 23° is too high and that the CCIR rain zones near the equator are too coarse.
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Efficient scheme of pole-zero system identification based on multilayer neural network
  • Author(s): B. Bhanu Murthy ; G. Panda ; C.F.N. Cowan
  • Source: Electronics Letters, Volume 29, Issue 1, p. 73 –75
  • DOI:  10.1049/el:19930048
  • Type: Article
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  • p. 73 –75 (3)
    A novel scheme to identify adaptive pole-zero filters, based on the multilayer neural network approach, is proposed using the conventional back propagation algorithm. The performance of the neural network is studied in a system identification application and simulation results are presented showing identical performance but computational superiority over a frequency domain adaptive pole-zero filter reported in the literature.
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Effect of capacitative imbalance on common-mode rejection of balanced photodetector pairs
  • Author(s): R.J. Deri  and  R. Welter
  • Source: Electronics Letters, Volume 29, Issue 1, p. 75 –77
  • DOI:  10.1049/el:19930049
  • Type: Article
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  • p. 75 –77 (3)
    The Letter shows that the common-mode rejection ratio of balanced photodetector pairs, as used for coherent lightwave reception, is insensitive to capacitance differences between the detectors in the absence of parasitic series impedance. These results indicate that balanced performance can be achieved in high-speed detector pairs, even when a capacitance imbalance occurs. The effect of detector series resistance or inductance on common mode rejection is quantitatively analysed.
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3.0 W blue light generation by frequency doubling of broad area semiconductor amplifier emission
Feedback implementation of signal recovery from nonuniform samples
Device for generating binary sequences for stochastic computing
Grating assisted vertical coupler/filter for extended tuning range
  • Author(s): L.L. Buhl ; R.C. Alferness ; U. Koren ; B.I. Miller ; M.G. Young ; T.L. Koch ; C.A. Burrus ; G. Raybon
  • Source: Electronics Letters, Volume 29, Issue 1, p. 81 –82
  • DOI:  10.1049/el:19930053
  • Type: Article
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  • p. 81 –82 (2)
    Broadly tunable, narrowband wavelength filters that can be integrated with other photonic devices are important elements for WDM multi/demultiplexing systems. Recently, we have demonstrated a broadly tunable, narrowband wavelength selective grating assisted vertical directional coupler with a 215 Å tuning range. In the Letter, an improved version of the vertically stacked buried rib InGaAsP/InP integrable wavelength filter that has a tuning range greater than 370 Å is reported.
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Finite-difference time-domain approach to nonlinear guided waves
Determination of the true value of the Euler totient function in the RSA cryptosystem from a set of possibilities
Simulation of influence of undoped spacer layers in Si/SiGe-HBTs on transit frequency
Single-step bandgap control in InGaAs/lnGaAlAs quantum well modulators via MeV implants
  • Author(s): Y. Chen ; J.E. Zucker ; B. Tell ; N.J. Sauer ; T.Y. Chang
  • Source: Electronics Letters, Volume 29, Issue 1, p. 87 –88
  • DOI:  10.1049/el:19930057
  • Type: Article
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  • p. 87 –88 (2)
    A large blue shift of the bandgap, 138 meV, in InGaAs/InGaAlAs quantum well pin modulators using a single-step MeV phosphorus ion implantation is reported. Current-voltage and photocurrent measurements show that the junction characteristic is well maintained. Moreover, we find that the blue-shifted quantum wells remain electro-optically active after implantation. Thus this technique, in addition to providing a means of producing side-by-side active and passive sections, is also promising for dual-wavelength active sections in a single quantum well wafer.
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Multibeam printed antenna arrays
  • Author(s): E. Motta Cruz  and  J.P. Daniel
  • Source: Electronics Letters, Volume 29, Issue 1, p. 88 –90
  • DOI:  10.1049/el:19930058
  • Type: Article
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  • p. 88 –90 (3)
    The design and realisation of two new types of microwave printed antenna array, which exhibit unusual radiation diagrams are described. Some ideas concerning the association of radiating elements into blocks are developed in order to synthesise important radiation functions: creation of multibeam patterns, reduction of the secondary lobe levels, elimination of some grating lobes and compensation for others.
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Selftuning control of nonminimum phase systems based on pole-zero placement using approximate inverse systems
Room temperature 600 mW CW output power per facet from single GaInAs/GaAs/GaInP large area laser diode grown by CBE
  • Author(s): Ph. Maurel ; J.C. Garcia ; Ph. Regreny ; J.P. Hirtz ; E. Vassilakis ; A. Parent ; M. Baldy ; C. Carrière
  • Source: Electronics Letters, Volume 29, Issue 1, p. 91 –93
  • DOI:  10.1049/el:19930060
  • Type: Article
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  • p. 91 –93 (3)
    Continuous wave output power levels of 600 mW at 25°C are reported from 100 μm wide, 300 μm long GaInAs/GaAs/GaInP large area laser diodes grown by CBE without any facet treatment. At these levels, the delivered current is 2 A, with an associated voltage of less than 1.7 V. The characteristic temperature of the structure is 95 K.
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Efficient systolic Broyden algorithm
  • Author(s): G.M. Megson
  • Source: Electronics Letters, Volume 29, Issue 1, p. 93 –94
  • DOI:  10.1049/el:19930061
  • Type: Article
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  • p. 93 –94 (2)
    An efficient systolic array for solving a system of n nonlinear equations using the quasi-Newton algorithm attributed to Broyden is proposed. The array is produced by a careful reformulation of the underlying iterative method as a sequence of Schur complements which can be computed systolically using the well-known Faddeev array as a basic building block. Further modifications to the basic array produces an efficient design which exhibits high throughput and which can be used iteratively.
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Motion adaptive spatial filter for temporal band limitation
Estimation method for three state compound channel model
(InAs)1/(GaAs)2 short period superlattice strained single quantum well laser on GaAs substrate
  • Author(s): H. Kurakake ; T. Uchida ; H. Soda ; S. Yamazaki
  • Source: Electronics Letters, Volume 29, Issue 1, p. 98 –99
  • DOI:  10.1049/el:19930064
  • Type: Article
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  • p. 98 –99 (2)
    The first MOVPE grown (InAs)1/(GaAs)2 short period super-lattice (SPS) strained quantum well laser at 1.07 μm is demonstrated. The SPS active layer has 10 periods of one and two monolayers of InAs and GaAs, and a total mismatch of over 2.2%. In a highly strained condition the device had a lasing wavelength of 1.07 μm, a threshold of 130 A/cm2 and a characteristic temperature T0 of 179 K.
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Non-existence of certain perfect binary arrays
Reliable 1.2W CW red-emitting (Al)GaInP diode laser array with AlGaAs cladding layers
Lateral current injection InGaAs/InAIAs MQW lasers grown by GSMBE/LPE hybrid method
Nonreciprocal behaviour of leaky gyrotropic waveguide
Radiation Q-factor of high-Tc, superconducting parallel-plate resonators
Decision gate for all-optical data retiming using a semiconductor laser amplifier in a loop mirror configuration
Smooth and monotonic phase variations in combined multiamplitude and multiphase modulation
  • Author(s): A. Kourtis ; C. Vassilopoulos ; C. Mantakas
  • Source: Electronics Letters, Volume 29, Issue 1, p. 109 –110
  • DOI:  10.1049/el:19930071
  • Type: Article
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  • p. 109 –110 (2)
    A smooth and monotonic phase variation technique in combined multiple amplitude and multiple phase modulation schemes, is investigated. Computer simulation is used to show that the proposed technique achieves a 20% reduction in the mainlobe width of the transmitted signal and suppresses the sidelobe level by 20dB, as compared with conventional techniques, for abrupt phase transitions.
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1.47 μm band Tm3+ doped fluoride fibre amplifier using a 1.064 μm upconversion pumping scheme
Multiplexed Bragg grating fibre-laser strain-sensor system with mode-locked interrogation
1 Gbit/s coherent optical communication system using a 1 W optical power amplifier
  • Author(s): S.B. Alexander ; E.S. Kintzer ; J.C. Livas ; J.N. Walpole ; C.A. Wang ; L.J. Missaggia ; S.R. Chinn
  • Source: Electronics Letters, Volume 29, Issue 1, p. 114 –115
  • DOI:  10.1049/el:19930074
  • Type: Article
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  • p. 114 –115 (2)
    An experimental 1 Gbit/s, coherent optical communication system that uses a 1 W semiconductor optical power amplifier is reported. The system is intended for use in free-space crosslink applications, operates at a wavelength of 972 nm and uses a frequency-shift-key (FSK) modulated semiconductor laser master oscillator, heterodyne detection receiver, and delay-line discriminator demodulator. Communication link sensitivities of 30 detected photons per bit at a 10-6 bit error rate have been obtained. This link performance can support gigabit per second rates across geosynchronous distances.
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Ozone oxidation of silicon
CCII-based fuzzy membership function and max/min circuits
Analogue fault identification based on power supply current spectrum
Generation of ultrahigh repetition rate soliton trains in fibre ring
Impulse noise protection with 4-D TCM
Analytical modelling of the programmed window in FLOTOX EEPROM cells
Monolithic integration of 2×2 switch and optical amplifier with 0 dB fibre to fibre insertion loss grown by LP-MOCVD
  • Author(s): G. Glastre ; D. Rondi ; A. Enard ; E. Lallier ; R. Blondeau ; M. Papuchon
  • Source: Electronics Letters, Volume 29, Issue 1, p. 124 –126
  • DOI:  10.1049/el:19930081
  • Type: Article
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  • p. 124 –126 (3)
    1.55 μm GaInAsP-InP optical amplifiers monolithically integrated with a directional coupler provide 0 dB fibre to fibre insertion loss at 140 mA of injected current in the amplifier and a -25 dBm input optical power. The crosstalk and extinction ratios are larger than 17 dB and the driving current to switch from the bar to the cross state is less than 6 mA.
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Modified spice modelling of DC characteristics for high-voltage DMOS transistors
  • Author(s): M.J. Zhou ; A. de Bruycker ; A. van Calster ; J. Witters ; G. Schols
  • Source: Electronics Letters, Volume 29, Issue 1, p. 126 –127
  • DOI:  10.1049/el:19930082
  • Type: Article
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  • p. 126 –127 (2)
    An improved SPICE DC model for high-voltage DMOS transistors is proposed by considering the drift resistance modulation by both the gate and the drain voltages. A nonlinear voltage controlled voltage source (VCVS) is introduced to represent this modulation. Results calculated from this model agree well with the experimental curves of the device DC characteristics.
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Analysis of radiation from active microstrip antennas
  • Author(s): P.S. Hall
  • Source: Electronics Letters, Volume 29, Issue 1, p. 127 –129
  • DOI:  10.1049/el:19930083
  • Type: Article
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  • p. 127 –129 (3)
    The analysis of active microstrip antennas consisting of patches or other microstrip radiators integrated with active devices such as matched amplifiers is described. The analysis uses circuit voltages generated by the TOUCHSTONE analysis package as source distribution for a magnetic current radiation calculation to allow estimation of the radiation behaviour of the integrated antenna. Results for radiation from a matched amplifier are close to those measured and calculations of radiation from active patches show that pattern perturbation due to unwanted circuit radiation can be substantial.
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