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Online ISSN 1350-911X Print ISSN 0013-5194

Electronics Letters

Volume 24, Issue 7, 31 March 1988

Volumes & issues:

Volume 24, Issue 7

31 March 1988

Bandwidth-limited, single longitudinal mode ps optical pulse generation from a strongly RF-modulated distributed feedback GaInAsP diode laser at 1.54 μm
  • Author(s): N. Zhang ; H. Ito ; H. Inaba
  • Source: Electronics Letters, Volume 24, Issue 7, p. 369 –370
  • DOI:  10.1049/el:19880249
  • Type: Article
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  • p. 369 –370 (2)
    Bandwidth-limited, single longitudinal mode ultrashort optical pulse generation from a GaInAsP DFB diode laser at 1.54μm was realised for the first time using the simplest method of strong RF modulation superimposed on the controlled DC bias current. A typical time-bandwidth product of 0.44, with a FWHM of about 37.5 ps at 500 MHz modulation, proves quasi-Lorentzian shaped optical pulses of excellent coherent character.
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Dielectric grating induced by cavity standing wave as a new explanation of origin of nonlinear gain in semiconductor diode lasers
  • Author(s): C.B. Su
  • Source: Electronics Letters, Volume 24, Issue 7, p. 370 –371
  • DOI:  10.1049/el:19880250
  • Type: Article
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  • p. 370 –371 (2)
    The nonlinear gain due to induced index and gain grating caused by the cavity standing wave is analysed using coupled-mode equations. The grating coupling coefficient is calculated using the rate equation with an ambipolar diffusion term. The self-consistent solution of the coupling coefficient and the optical field indicate the existence of a nonlinear gain term with a surprisingly large magnitude. This gain nonlinearity is shown to contribute significantly to the modulation damping factor of semiconductor diode lasers.
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Synthetic aperture processing for full-deramp radar altimeters
Fast turnoff in optical switching of low-finesse GaAs etalons operating in reflection
Effect of substrate on current distribution of feeding probe
Discussion of HS formulation using equivalent current theory
  • Author(s): Wu Yizun
  • Source: Electronics Letters, Volume 24, Issue 7, p. 376 –377
  • DOI:  10.1049/el:19880254
  • Type: Article
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  • p. 376 –377 (2)
    The coupled mode formulation of Hardy and Streifer (HS) is currently under discussion. To settle this argument I derive the HS formulation by the equivalent current theory of optical waveguide coupling, and hence show that the HS formulation is based upon the same principles of the common coupling equation and is correct only under the weakly coupling condition. By making this clear and defining the weakly coupling condition quantitatively, the debate may be closed.
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Parasitic-compensated switched-capacitor delay lines
Ga1−yInyAs/InAsxP1−x (y > 0.53, x > 0) pin photodiodes for long wavelength regions (λ > 2μm) grown by hydride vapour phase epitaxy
  • Author(s): K. Makita ; T. Torikai ; H. Ishihara ; K. Taguchi
  • Source: Electronics Letters, Volume 24, Issue 7, p. 379 –380
  • DOI:  10.1049/el:19880256
  • Type: Article
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  • p. 379 –380 (2)
    pin photodiodes with a 2.3 μm absorption edge are presented, using hydride vapour phase epitaxy. A Ga1−yInyAs (y = 0.72) absorption layer, lattice-mismatched to the InP substrate, was grown on an InAsxP1−x (x = 0–0.33) graded composition buffer layer. Typical dark current was 5 μA (0.03 A/cm2) at −6V. Effective carrier lifetime of 0.05 μs is was estimated from I/V characteristics.
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Statistics of layer formation in Mersa Matruh, Egypt
New hardware architecture for fast raster image generation
pn+ junction in an implanted electroactive polymer: poly(paraphenylene)
  • Author(s): A. Moliton ; J.L. Duroux ; B. Ratier ; G. Froyer
  • Source: Electronics Letters, Volume 24, Issue 7, p. 383 –385
  • DOI:  10.1049/el:19880259
  • Type: Article
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  • p. 383 –385 (3)
    We have recently shown that specific and stable n or p doping may be obtained on poly(paraphenylene) providing moderate implantation conditions with appropriate ions are used. Here we describe a pn+ -junction made in intrinsic insulating poly(paraphenylene) (σ <10−12 Ω −1 cm−1) by implantation (E ⋍ 50keV) of alkali metal ions (essentially caesium for n doping) and halogen (iodine for p doping).
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New focusing and dispersive planar component based on an optical phased array
Accurate pattern synthesis of parallel dipole arrays and its application to unequal elements
Transmission of FDM wideband data and video channels over a single-mode fibre using 1300 nm LED
  • Author(s): P.S. Venkatesan ; P.S. Natarajan ; J. Orost
  • Source: Electronics Letters, Volume 24, Issue 7, p. 387 –389
  • DOI:  10.1049/el:19880262
  • Type: Article
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  • p. 387 –389 (3)
    The transmission of two frequency-division-multiplexed full motion network quality video channels and one digital ISDN-H1 channel over a repeaterless single-mode fibre in excess of eleven kilometres using a LED operating at 1300 nm wavelength is demonstrated. Transmitted video quality, and bit error rate performance of the digital channel are reported. Experimental system components and procedures are described in detail.
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LED spectral slicing for single-mode local loop applications
  • Author(s): M.H. Reeve ; A.R. Hunwicks ; W. Zhao ; S.G. Methley ; L. Bickers ; S. Hornung
  • Source: Electronics Letters, Volume 24, Issue 7, p. 389 –390
  • DOI:  10.1049/el:19880263
  • Type: Article
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  • p. 389 –390 (2)
    An approach towards a single-mode local loop is presented in which each customer is given a dedicated wavelength channel by taking different wavelength slices from identical LEDs. This is accomplished by means of wavelength division multiplexing (WDM) components. Results from a fourchannel system operating at 2 Mbit/s over 2.2 km, together with a theoretical analysis of a ten-channel system, are presented.
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Experimental set-up for dynamic evaluation of optical parameters of liquid samples exposed to microwave radiation
Variable bit rate transmission of television signals
Multilevel sequences with good autocorrelation properties
High-speed monolithic GaInAs pinFET
High contrast GaInAs:Fe photoconductive optical and gate for time-division demultiplexing
  • Author(s): E. Desurvire ; B. Tell ; I.P. Kaminow ; G.J. Qua ; K.F. Brown-Goebeler ; B.I. Miller ; U. Koren
  • Source: Electronics Letters, Volume 24, Issue 7, p. 396 –397
  • DOI:  10.1049/el:19880268
  • Type: Article
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  • p. 396 –397 (2)
    A high-contrast, three port optical AND gate based on the photoconductive effect in Ga0.47In0.53As:Fe and operating in the λ = 1.3–5 μm wavelength range is demonstrated. A 250: 1 optical power contrast ratio (or 48 dB in electrical power after detection) is obtained in an optical-to-optical time division demultiplexing of a 100 MHz pulse train by a 6.25 MHz clock, both at λ = 1.3 μm, with the demultiplexed output pulses at λ = 1.5 μm.
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Adaptive quantised feedback equalisation for FSK heterodyne transmission at 150 Mbit/s and 1 Gbit/s
First sea trial of FSK heterodyne optical transmission system using polarisation diversity
90° reflecting mirrors in Ti:LiNbO3 waveguide structures
Acousto-optic spectrum analysis using white light
Floating immittance realisation: nullor approach
  • Author(s): R. Senani
  • Source: Electronics Letters, Volume 24, Issue 7, p. 403 –405
  • DOI:  10.1049/el:19880273
  • Type: Article
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  • p. 403 –405 (3)
    Employing ‘CCII⊖/nullor equivalence’ a number of new CC-based single-resistance-tunable floating-L, and FDNR circuits are derived which require only two CCs and three passive elements, and do not require passive component-matching. Also, the unifying role of the nullor approach in relating a variety of practicable floating immittance structures obtainable by using different kinds of active devices is highlighted.
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Conjugate gradient algorithm based on matrix representation of linear operators in finite dimensional Hilbert spaces
Degradations in Gbit/s DFB laser transmission systems due to phase-to-intensity noise conversion by multiple reflection points
  • Author(s): J.L. Gimlett ; J. Young ; R.E. Spicer ; N.K. Cheung
  • Source: Electronics Letters, Volume 24, Issue 7, p. 406 –408
  • DOI:  10.1049/el:19880275
  • Type: Article
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  • p. 406 –408 (3)
    Severe system degradations and bit error rate floors are observed in Gbit/s fibre transmission systems due to the interferometric conversion of laser phase noise to intensity noise by multiple reflections from connectors and splices. Studies of penalties as a function of both the magnitude and number of reflections indicate that fibre joints with guaranteed minimum return losses of better than 20dB may be required for high-speed direct detection systems as well as future coherent systems, even though optical isolators may be employed in such systems.
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Silicon epitaxy at low temperature, using UV cleaning in a reduced pressure CVD system
Multiplexed fibre-optic interferometric sensing system: combined frequency and time division
Relation between new ‘field radius’ w∞ and petermann II field radius wd in single-mode fibres with arbitrary refractive index profile
Endless polarisation controller using electro-optic waveplates
Coplanar waveguide array antenna
Switching operation in intersectional type field effect MQW optical switch
  • Author(s): K.G. Ravikumar ; K. Shimomura ; T. Kikugawa ; A. Izumi ; S. Arai ; Y. Suematsu ; S. Matsubara
  • Source: Electronics Letters, Volume 24, Issue 7, p. 415 –416
  • DOI:  10.1049/el:19880281
  • Type: Article
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  • p. 415 –416 (2)
    Switching operation in an intersectional-type field effect multiquantum-well optical switch was observed for the first time from light reflection caused by the electric-field-induced refractive index variation and absorption coefficient change. The letter reports switching operation in a GaInAsP/InP MQW ridge waveguide structure with an intersection angle of 4°. Polarisation dependent properties originating from the quantum-well structure were also observed.
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660 nm wavelength GaInAsP/AlGaAs distributed feedback lasers
  • Author(s): T. Chong  and  K. Kishino
  • Source: Electronics Letters, Volume 24, Issue 7, p. 416 –418
  • DOI:  10.1049/el:19880282
  • Type: Article
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  • p. 416 –418 (3)
    GaInAsP/AlGaAs distributed feedback (DFB) lasers emitting at 660 nm were fabricated by liquid phase epitaxy for the first time. DFB mode oscillation in a single longitudinal mode was observed in the temperature range from 22°C to −24°c and in the current range up to 1.25 times the threshold (here, the output power was 5 mW). The temperature dependence of lasing wavelength was as small as 0.04 nm/deg.
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Capacitance-based tomographic flow imaging system
Square-law detected synthetic aperture radar
Efficient priority-scheduling algorithm for integrated packet-switched systems
Block error probability of narrowband digital FM with frequency detection in land mobile radio
Performance of an ordered statistic CFAR processor in log-normal clutter
Multiparabolic ionospheric model for SSL application
  • Author(s): D.C. Baker  and  S. Lambert
  • Source: Electronics Letters, Volume 24, Issue 7, p. 425 –426
  • DOI:  10.1049/el:19880288
  • Type: Article
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  • p. 425 –426 (2)
    A simple model for ionospheric electron concentration, based on continuous multiparabolic regions, is proposed. Analytic solutions for the virtual height of reflection at vertical incidence, in the absence of a magnetic field, are discussed. Extension to estimating ground range and ray-apogee heights at oblique incidence is possible with potential applications for single site location (SSL) HF direction finding (DF) systems.
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Performance of coded M-ary noncoherent frequency-shift keying for threshold communications
Simple model for frequency modulation characteristics of semiconductor lasers
Frequency stabilisation of a semiconductor laser using Rb-D1 and D2 absorption lines
Longitudinal mode selectivity above threshold for asymmetric mirror structure DFB lasers with low front facet reflectivity
  • Author(s): H. Soda ; H. Ishikawa ; H. Imai
  • Source: Electronics Letters, Volume 24, Issue 7, p. 431 –432
  • DOI:  10.1049/el:19880292
  • Type: Article
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  • p. 431 –432 (2)
    We analysed longitudinal mode selectivity above threshold for asymmetric mirror structure DFB lasers which have a low front facet reflectivity by taking spatial hole burning into account. As a result we found that single longitudinal mode (SLM) operation yield cannot be improved by an introduction of front facet reflectivity for KL of 0.75. There was no strong KL dependence of the SLM operation yield for a low-noise DFB laser with a front facet reflectivity of 0.05.
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SC bilinear band-elimination ladder filters with extended biquad
Use of n+ spike doping regions as nonequilibrium connectors
Novel single-longitudinal-mode 1.5 μm GaInAsP/InP distributed reflector (DR) laser
  • Author(s): S. Pellegrino ; K. Komori ; H. Suzuki ; K. Lee ; K.S. Arai ; K. Suematsu ; K. Aoki
  • Source: Electronics Letters, Volume 24, Issue 7, p. 435 –437
  • DOI:  10.1049/el:19880295
  • Type: Article
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  • p. 435 –437 (3)
    A novel single-longitudinal-mode laser aiming at high-power operation as well as high fabrication yield is proposed and was realised by employing a bundle-integrated-guide (BIG) structure for efficiently coupled active and passive distributed reflector regions. Low threshold current CW operation and an asymmetric emission property were obtained with a high submode suppression ratio (SMSR) of 38 dB at an output power level of 7 mW.
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Equivalent circuit models of switches for SPICE simulation
Amplification and lasing at 1350 nm in a neodymium doped fluorozirconate fibre
Phase-locked induction heating inverter employing power MOSFETs
Optical heterodyne image rejection receiver
20 km single-mode optical fibre system for multichannel video
Piezoelectric transformers
  • Author(s): E. Dieulesaint ; D. Royer ; D. Mazerolle ; P. Nowak
  • Source: Electronics Letters, Volume 24, Issue 7, p. 444 –445
  • DOI:  10.1049/el:19880301
  • Type: Article
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  • p. 444 –445 (2)
    These transformers are composite resonators made of two bonded piezoelectric parts. The vibration of one part, excited by an input electric voltage, induces an output voltage across the other part. The polarisation of the parts and the location of the electrodes are chosen so that the output voltage is more than 1000 times greater than the input voltage at the resonance frequency (≃80kHz or 160 kHz).
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Erratum: Chirp-induced penalty in optical fibre systems

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