Online ISSN
1350-911X
Print ISSN
0013-5194
Electronics Letters
Volume 21, Issue 20, 26 September 1985
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Volume 21, Issue 20
26 September 1985
Holographically formed, highly selective. infra-red filter in iron-doped lithium niobate
- Author(s): P. Mills and E.G.S. Paige
- Source: Electronics Letters, Volume 21, Issue 20, p. 885 –886
- DOI: 10.1049/el:19850624
- Type: Article
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The novel fabrication method and the performance of a volume holographic filter is described. Formed in a crystal of 0.04 mol% iron-doped lithium niobate the filter has an angular selectivity of 0.13° and a wavelength selectivity of less than 1 Å at a wavelength of 1.15 μm.
Improved frequency response of InP/InGaAsP/InGaAs avalanche photodiodes with separate absorption, grading and multiplication regions
- Author(s): W.S. Holden ; J.C. Campbell ; J.F. Ferguson ; A.G. Dentai ; Y.K. Jhee
- Source: Electronics Letters, Volume 21, Issue 20, p. 886 –887
- DOI: 10.1049/el:19850625
- Type: Article
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We report very high-speed operation of InP/InGaAsP/InGaAs avalanche photodiodes with separate absorption, grading and multiplication regions (SAGM-APDs). For low multiplication values (M0≤7) the bandwidth of these APDs is relatively insensitive to the gain and is determined by the hole transit time and the RC time constant. In this gain region bandwidths as high as 5.5 GHz have been achieved. For higher multiplication values the frequency response exhibits a constant gain-bandwidth product. We have observed gain-bandwidth products as high as 40 GHz, the highest value reported to date for a device of this type.
High-power, low-threshold BH lasers operating at 1.52 μm grown entirely by MOVPE
- Author(s): A.W. Nelson ; W.J. Devlin ; R.E. Hobbs ; C.G.D. Lenton ; S. Wong
- Source: Electronics Letters, Volume 21, Issue 20, p. 888 –889
- DOI: 10.1049/el:19850626
- Type: Article
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BH laser devices with efficient optical and current confinement have been grown using a new all-MOVPE growth technique. The devices produced operated with CW threshold currents as low as 14 mA and output powers of up to 28 mW at 20°C. In initial experiments, over 70% of the working devices tested had threshold currents of less than 30 mA, substantiating the view that MOVPE is a highly promising technique for the large-scale production of complex optoelectronic devices.
New Rc-Active oscillator configuration employing unity-gain amplifiers
- Author(s): R. Senani
- Source: Electronics Letters, Volume 21, Issue 20, p. 889 –891
- DOI: 10.1049/el:19850627
- Type: Article
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A new sinusoidal oscillator configuration is proposed which employs op-amps as unity-gain amplifiers. The proposed circuit offers independent single-element controls for adjusting the condition of oscillation and oscillation frequency and has very good frequency stability. Practically, the circuit works well over a frequency range much higher than possible with other known types of oscillators (which use op-amps as ±K-gain or infinite-gain VCVSs). The proposed configuration also provides useful prototypes to derive novel switched-capacitor oscillators.
New logic array concept with high flexibility
- Author(s): W. Brockmann ; H. Vogt ; R. Weiss
- Source: Electronics Letters, Volume 21, Issue 20, p. 891 –892
- DOI: 10.1049/el:19850628
- Type: Article
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A logic array concept called ELA (extended logic array) is described, which consists of a modified PLA arrangement and a special form of matrix lines. The regular structure leads to high flexibility and may allow an automated design based on an abstract functional description.
Method of calculating minimum distance for suboptimum receivers
- Author(s): W. Holubowicz
- Source: Electronics Letters, Volume 21, Issue 20, p. 892 –893
- DOI: 10.1049/el:19850629
- Type: Article
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A method of calculating the minimum distance for suboptimum receivers is presented. The amount of computation required to calculate the minimum distance by this method is significantly less than by the method used previously. If the value of a parameter is well chosen the results are the same in both methods.
Measurement of nonlinear gain from FM modulation index of InGaAsP lasers
- Author(s): C.B. Su ; V. Lanzisera ; R. Olshansky
- Source: Electronics Letters, Volume 21, Issue 20, p. 893 –895
- DOI: 10.1049/el:19850630
- Type: Article
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The contribution of nonlinear gain to the FM modulation index and relaxation oscillation damping factor for a multi-mode laser is calculated and measured. The nonlinear gain term obtained from the measured FM modulation index of a 1.3 μm InGaAsP laser is used to predict the optical intensity modulation response. Excellent agreement between prediction and observation are obtained.
New polarisation-state control device: rotatable fibre cranks
- Author(s): T. Okoshi ; N. Fukaya ; K. Kikuchi
- Source: Electronics Letters, Volume 21, Issue 20, p. 895 –896
- DOI: 10.1049/el:19850631
- Type: Article
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A new all-fibre device for controlling the state of polarisation (SOP) in a single-mode fibre is proposed. It consists of two fibre elements called rotatable fibre crank (RFC) elements, each of which is equivalent to a rotatable phase plate. It features a very low insertion loss when used in a fibre circuit, because it can be spliced with input and output fibres, and that the control is endless as in a rotatable phase plate. The effectiveness of the SOP control using this device is verified experimentally.
Broadband conical microstrip antenna
- Author(s): L. Jeddari ; K. Mahdjoubi ; C. Terret ; J.P. Daniel
- Source: Electronics Letters, Volume 21, Issue 20, p. 896 –898
- DOI: 10.1049/el:19850632
- Type: Article
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Conical patch antennas, excited on TE11-mode are studied and their resonance frequencies are computed. These antennas present a broader bandwidth compared to classical microstrip antennas and, furthermore, good impedance matching can be easily obtained.
New approach for determining non-Gaussian mode fields of single-mode fibres from measurements in far field
- Author(s): C. Saravanos and R.S. Lowe
- Source: Electronics Letters, Volume 21, Issue 20, p. 898 –899
- DOI: 10.1049/el:19850633
- Type: Article
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The far-field RMS width of a single-mode fibre is shown to be related to the first derivative of the power passed through a circular aperture. This relationship allows a direct determination of Petermann's recent definition of mode field radius from data collected using the far-field variable-aperture technique.
Efficient technique for solving nonlinear mixer pumping problem
- Author(s): P.W. van der Walt
- Source: Electronics Letters, Volume 21, Issue 20, p. 899 –900
- DOI: 10.1049/el:19850634
- Type: Article
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An efficient technique for solving the nonlinear mixer pumping problem is described. The technique can be applied to mixer configurations where the impedance presented to the diode at the local oscillator frequency and its harmonics are known.
Modified algorithm for block truncation coding of monochrome images
- Author(s): V. Udpikar and J.P. Raina
- Source: Electronics Letters, Volume 21, Issue 20, p. 900 –902
- DOI: 10.1049/el:19850635
- Type: Article
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Block truncation coding (BTC) is a recent technique used in the coding of image data. In the letter a modified technique for BTC coding of image data is presented which is algorithmically simple and hence easy to implement. This new technique uses only the first-order statistical information as ‘block overhead’. The new algorithm is shown to be optimum in the mean-square sense for a particular class of BTC algorithms. The letter presents the results of using the new algorithm for a typical image and compares the performance with that of the earlier algorithm for the same image.
Hydrogen generation due to decomposition of carboxym ethyl-cellulose in muddy water
- Author(s): H. Koga ; Y. Mitsunaga ; T. Kuwabara
- Source: Electronics Letters, Volume 21, Issue 20, p. 902 –903
- DOI: 10.1049/el:19850636
- Type: Article
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The letter describes a novel hydrogen generation phenomenon observed for carboxymethyl-cellulose (CMC), used as a typical material for water-swellable tape in waterproof optical cable. A graded-index optical fibre set in CMC solution containing muddy water exhibits optical loss increase due to hydrogen gas generation, and the viscosity of the CMC solution decreases because of micro-organism decomposition.
Complementary self-aligned laser by metalorganic chemical vapour deposition
- Author(s): L.J. Mawst ; G. Costrini ; C.A. Zmudzinski ; M.E. Givens ; M.A. Emanuel ; J.J. Coleman
- Source: Electronics Letters, Volume 21, Issue 20, p. 903 –905
- DOI: 10.1049/el:19850637
- Type: Article
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A complementary two-step MOCVD growth technique for the self-aligned laser is described which eliminates any possible difficulty associated with regrowth on a high composition AlGaAs layer by placing the regrowth interface outside the stripe region. Single-longitudinal-mode operation with stable near and far-field patterns has been obtained to more than twice the laser threshold current.
Comment: Determination of P-adic transform bases and lengths
- Author(s): R.N. Gorgui-Naguib and A. Leboyer
- Source: Electronics Letters, Volume 21, Issue 20, p. 905 –906
- DOI: 10.1049/el:19850638
- Type: Article
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Reply: Determination of P-adic transform bases and lengths
- Author(s): Soo-Chang Pei and Wu Ja-Ling
- Source: Electronics Letters, Volume 21, Issue 20, page: 906 –906
- DOI: 10.1049/el:19850639
- Type: Article
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High-speed large-signal digital modulation of a 1.3 μm InGaAsP constricted mesa laser at a simulated bit rate of 16 Gbit/s
- Author(s): Chinlon Lin and J.E. Bowers
- Source: Electronics Letters, Volume 21, Issue 20, p. 906 –908
- DOI: 10.1049/el:19850640
- Type: Article
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Recently, high-frequency 1.3μm InGaAsP constricted mesa lasers have shown a small-signal –3 dB bandwidth of more than 15 GHz at 15°C, and have been modulated with pseudorandom pulses at 8 Gbit/s (NRZ format). The letter reports large-signal digital modulation of such a constricted mesa laser using time-multiplexed electrical pulses 80 Ps in duration and 125 Ps apart which demonstrates the high-speed modulation capability of this laser at a simulated bit rate of 16 Gbit/s (NRZ).
Novel type of broadband travelling-wave integrated-optic modulator
- Author(s): A. Djupsjöbacka
- Source: Electronics Letters, Volume 21, Issue 20, p. 908 –909
- DOI: 10.1049/el:19850641
- Type: Article
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We propose and analyse a novel type of baseband travelling-wave integrated-optic modulator which has a broadened baseband response compared with corresponding modulators of conventional design. Numerical calculations are reported for this novel structure, and a comparison of figures of merit for the novel modulator and conventional types is given.
Cost-effective digital switching network
- Author(s): A. Jajszczyk
- Source: Electronics Letters, Volume 21, Issue 20, p. 909 –910
- DOI: 10.1049/el:19850642
- Type: Article
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A method for the design of cost-effective one-stage PCM switching networks composed of uniform time-space elements is proposed. These one-stage networks can be used as submodules for multistage networks, having, in many cases, fewer elements than currently known networks.
On common factors appearing in inversion of matrix transfer functions
- Author(s): M.B. Argoun
- Source: Electronics Letters, Volume 21, Issue 20, p. 910 –912
- DOI: 10.1049/el:19850643
- Type: Article
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Two identities that appear when inverting a transfer function matrix T(s)=C(SI-A)−1B are proven. They lead to significant simplification in the computation of T−1(s)
General equation for quasisinusoidal oscillators
- Author(s): A. Buonomo ; C. di Bello ; O. Greco
- Source: Electronics Letters, Volume 21, Issue 20, p. 912 –913
- DOI: 10.1049/el:19850644
- Type: Article
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A nonlinear differential equation has been obtained to describe the behaviour of any quasisinusoidal oscillator, Simple relationships are also proposed whereby the frequency and amplitude of an oscillation can be calculated and its stability verified. Application examples involving some typical circuits are then given.
High-power pulsed beam-lead IMPATT diodes for millimetre waves
- Author(s): R. Pierzina and J. Freyer
- Source: Electronics Letters, Volume 21, Issue 20, p. 913 –915
- DOI: 10.1049/el:19850645
- Type: Article
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IMPATT diodes with technologically integrated beam-leads were fabricated. Since no diode bonding is required, a total diode thickness of less than 2 μm can be realised reproducibly. With optimum device packages, peak pulse output powers of more than 10 W at 70 GHz have been achieved from silicon single-drift IMPATT diodes.
Wide-bandwidth, sharp-cutoff bandpass filter for WDM transmission
- Author(s): J. Minowa and Y. Fujii
- Source: Electronics Letters, Volume 21, Issue 20, p. 915 –916
- DOI: 10.1049/el:19850646
- Type: Article
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A new interference bandpass filter for use in optical multi/demultiplexers is presented. This filter is a 37-layer, 5-cavity filter made of TiO2 and SiO2. The cavity layers are the 4th, 11th, 19th, 27th and 34th layers. A fabricated filter (centre wavelength at 1.3 μm) had a 77 nm bandwidth and a 0.64 dB/nm cutoff slope. The transmittance in the passband was 0.97 or greater.
Linearly birefringent fibres with zero polarisation-mode dispersion
- Author(s): K.S. Chiang
- Source: Electronics Letters, Volume 21, Issue 20, p. 916 –917
- DOI: 10.1049/el:19850647
- Type: Article
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It is found that in a single-mode optical fibre, if the material anisotropy in the cladding can be made substantially larger than that in the core, the group delays of the two orthogonally polarised modes can be equalised at some particular frequencies. Numerical results are presented for circular and elliptical fibres.
Further note on mB1C code spectra
- Author(s): J.J. O'Reilly
- Source: Electronics Letters, Volume 21, Issue 20, page: 918 –918
- DOI: 10.1049/el:19850648
- Type: Article
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It is shown that the power spectral density for mB1C line-coded signals may be readily derived without recourse to a finite-state-machine model and computer aids.
Three-terminal operation of InAs-coupled Josephson devices by quasiparticle injection
- Author(s): K. Inoue and T. Kawakami
- Source: Electronics Letters, Volume 21, Issue 20, p. 918 –920
- DOI: 10.1049/el:19850649
- Type: Article
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Three-terminal Nb/InAs/Nb Josephson junctions with a metal-semiconductor (MES) gate are developed. Super-current is controlled by injecting quasiparticles into the coupling region. The devices have a planar geometry with a self-aligned gate isolation using Nb native oxide.
Low-loss and low-crosstalk polarisation-maintaining optical fibres
- Author(s): T. Hosaka ; Y. Sasaki ; J. Noda ; M. Horiguchi
- Source: Electronics Letters, Volume 21, Issue 20, p. 920 –921
- DOI: 10.1049/el:19850650
- Type: Article
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A transmission loss of 0.25 dB/km at 1.57 μm wavelength, which is comparable to that found in commercially available single-mode fibres, has been demonstrated in PANDA optical fibres. A crosstalk of −29 dB in a 2.4 km length, which corresponds to the mode coupling coefficient of 5.2 × 10−7 m−1, has been found in the 1.55 μm wavelength region.
Minimisation of phase error in digitally controlled attenuator
- Author(s): T.B. Vu and K.W. Lo
- Source: Electronics Letters, Volume 21, Issue 20, p. 921 –922
- DOI: 10.1049/el:19850651
- Type: Article
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With null steering by amplitude-only control, it is essential that phase errors introduced by attenuators be as small as possible. A method of minimising phase errors is discussed. It is shown that very small phase errors over the whole attenuation range can be obtained if more diodes are used.
All-fibre sensing loop using pulse-modulated light-emitting diode
- Author(s): G. Adamovsky
- Source: Electronics Letters, Volume 21, Issue 20, p. 922 –923
- DOI: 10.1049/el:19850652
- Type: Article
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A sensing system is presented which includes a pulse-modulated light-emitting diode (LED) and an all-fibre-optic loop generating a reference signal in the time domain. The basic principle of operation and parameters are introduced, and some properties of such a system are experimentally examined using a microbend sensor.
High-speed 16 × 16 CMOS crosspoint switch
- Author(s): G.A. Hayward ; A.M. Gottlieb ; D.G. Boyer ; J.E. Berthold
- Source: Electronics Letters, Volume 21, Issue 20, p. 923 –925
- DOI: 10.1049/el:19850653
- Type: Article
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A 16 × 16 CMOS crosspoint capable of switching digitised video signals is presented. It was fabricated with a 3 μm double-level metal CMOS process and is shown to switch signals with data rates of 140 Mbit/s.
Optimised HEMT structure with an Al0.45 Ga0.55As spacer and an Al0.20Ga0.80As doped region
- Author(s): J.C. Huang ; G.W. Wicks ; A.R. Calawa ; L.F. Eastman
- Source: Electronics Letters, Volume 21, Issue 20, p. 925 –926
- DOI: 10.1049/el:19850654
- Type: Article
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We have obtained an optimised HEMT structure with a high 2DEG sheet concentration of 1×1012 cm−2 while maintaining a high 77 K electron Hall mobility of 120,000 cm2/Vs. The structure utilises a 45% Al mole fraction AlGaAs barrier and a 20% Al mole fraction doped region. It has little or no light sensitivity at 77 K.
Static and dynamic fatigue tests of abraded optical fibre
- Author(s): K. Abe and R. Ernst
- Source: Electronics Letters, Volume 21, Issue 20, p. 926 –928
- DOI: 10.1049/el:19850655
- Type: Article
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Static and dynamic fatigue tests were performed for abraded low-strength fibres and normal fibres. The analysis of the test results based on a bond dissociation model confirms the validity of the model and demonstrates that the two tests are equivalent. The implications of these results on lifetime estimation are discussed.
Bidirectional LED transmission on single-mode fibre in the 1300 and 1500 nm wavelength regions
- Author(s): M. Stern ; J.L. Gimlett ; L. Curits ; N.K. Cheung ; M.B. Romeiser ; W.C. Young ; P.W. Shumate
- Source: Electronics Letters, Volume 21, Issue 20, p. 928 –929
- DOI: 10.1049/el:19850656
- Type: Article
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Bidirectional transmission was demonstrated over 15 km of standard single-mode fibre using 1300 and 1500 nm edge-emitting LEDs at 140 Mbit/s and 45 Mbit/s, respectively. The bidirectional WDM filters, including two connectors, contributed 3.2 dB insertion loss in the 1300 nm channel and 2.6 dB in the 1500 nm channel. Spectral filtering introduced by the WDM devices reduced the dispersion penalty from 1.0 dB to 0.2 dB for the 1300 nm channel, and from 3.6 dB to 2.7 dB for the 1500 nm channel. The available system margins were 3.3 dB for the 140 Mbit/s channel and 8.0 dB for the 45 Mbit/s channel.
New method to measure facet reflectivity of antireflection (AR)-coated laser diodes and LEDs
- Author(s): J. Wang
- Source: Electronics Letters, Volume 21, Issue 20, p. 929 –931
- DOI: 10.1049/el:19850657
- Type: Article
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The facet reflectivity of AR-coated laser diodes and LEDs can be obtained by measuring the reflected optical power from the Fabry-Perot cavity formed by the flat end of a single-mode fibre and the diode facet. The relative error is estimated to be less than 10%. The estimation was based on the measurements on a conventional and an AR-coated 1.3 μm InGaAsP BH laser diode and the theoretical consideration of the light beam divergence and the angle misalignment of the cavity.
Room-temperature CW operation of AlGaInP double-heterostructure visible lasers
- Author(s): K. Kobayashi ; S. Kawata ; A. Gomyo ; I. Hino ; T. Suzuki
- Source: Electronics Letters, Volume 21, Issue 20, p. 931 –932
- DOI: 10.1049/el:19850658
- Type: Article
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Room-temperature continuous-wave (CW) operation of (Al0.4Ga0.6)0.5In0.5P/Ga0.5In0.5P/(Al0.4Ga0.6)0.5In0.5P double-heterostructure visible semiconductor lasers has been achieved for the first time. CW operation is obtained up to 50° C. The threshold current at 25° C is mA (4.1 kA/cm2). The lasing wavelength is 689.7 nm.
Correlation and aliasing in the noise-cancelling switched-capacitor (SC) filtering technique
- Author(s): A.G. Hall
- Source: Electronics Letters, Volume 21, Issue 20, p. 932 –933
- DOI: 10.1049/el:19850659
- Type: Article
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Analysis of correlation and aliasing in a sampled noise signal reconciles the differing results of two previous studies of noise cancellation in a switched-capacitor filter and introduces a technique for the further study of correlated noise cancellation.
Narrow-linewidth fibre-external-cavity injection lasers
- Author(s): K.-Y. Liou ; Y.K. Jhee ; C.A. Burrus ; K.L. Hall ; P.J. Anthony
- Source: Electronics Letters, Volume 21, Issue 20, p. 933 –934
- DOI: 10.1049/el:19850660
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A few-decimetre length of single-mode polarisation preserving fibre waveguide is used to provide stable linewidth-narrowing optical feedback to single-frequency injection lasers. Linewidth reductions by a factor of about 50 have been obtained for GRECC, C3 and DFB structures.
Evaluation of axial fibre strain based on the stimulated four-photon mixing process
- Author(s): T. Nakashima ; M. Shibata ; C.A. Ohashi ; S. Seikai
- Source: Electronics Letters, Volume 21, Issue 20, p. 935 –936
- DOI: 10.1049/el:19850661
- Type: Article
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The axial fibre strain is evaluated from measurement of the frequency shift of the anti-Stokes wave generated by the stimulated four-photon mixing process. The result evaluated experimentally is in good agreement with that predicted theoretically for a single-mode fibre with low intrinsic birefringence.
Dual-band microstrip antennas with monolithic reactive loading
- Author(s): S.E. Davidson ; S.A. Long ; W.F. Richards
- Source: Electronics Letters, Volume 21, Issue 20, p. 936 –937
- DOI: 10.1049/el:19850662
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The design and experimental measurement of a dual-band, monolithic microstrip antenna is presented. The structure utilises a short-circuited length of microstrip transmission line to provide reactive loading and, thereby, retains the low-profile characteristic of a normal microstrip patch radiator.
Cryogenic operation of pseudomorphic AlGaAs/InGaAs single-quantum-well MODFETs
- Author(s): W.T. Masselink ; A. Ketterson ; J. Klem ; W. Kopp ; H. Morkoç
- Source: Electronics Letters, Volume 21, Issue 20, p. 937 –939
- DOI: 10.1049/el:19850663
- Type: Article
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We have investigated the 77 K operation of AlGaAs/InGaAs MODFETs. The structures, grown by MBE, make use of a 200 Å undoped In0.15Ga0.85As quantum well for electron confinement and an Si-doped Al0.15Ga0.85As top barrier. The MODFETs with 1 μm gate lengths exhibit extrinsic transconductances of 360 mS/mm and maximum currents of 310 mA/mm at 77 K. The use of a low Al mole fraction AlGaAs/InGaAs heterojunction allows us to avoid the persistent trapping effects encountered in AlGaAs/GaAs MODFETs without sacrificing device performance.
Use of superluminescent diodes in PFM optical video transmission
- Author(s): T.T. Tjhung ; F.V.C. Mendis ; B. Selvan
- Source: Electronics Letters, Volume 21, Issue 20, p. 939 –940
- DOI: 10.1049/el:19850664
- Type: Article
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An 835 nm superluminescent diode with a spectral width of 8 nm is shown to reduce SNR fluctuations due to modal noise significantly in PFM optical video transmission. An SNR of 56 dB and DG/DP of 06%/0.3° are achieved over 5 km with a frequency deviation of only 400 kHz. The SNR fluctuation is less than 0.05 dB.
Offset and clock-feedthrough compensated switched-capacitor integrators
- Author(s): J. Robert ; G.C. Temes ; F. Krummenacher ; V. Valencic ; P. Deval
- Source: Electronics Letters, Volume 21, Issue 20, p. 941 –942
- DOI: 10.1049/el:19850665
- Type: Article
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941
–942
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Switched-capacitor integrator circuits are described, in which the effects of amplifier offset and clock feedthrough are both compensated for using a sampled-data feedback path. Preliminary experimental results, obtained on circuits fabricated using a low-voltage CMOS technology, indicate 40–60 dB reduction in these effects.
Effect on return loss of dimensional tolerances of the aperture of rectangular waveguide
- Author(s): E.J. Griffin and T.E. Hodgetts
- Source: Electronics Letters, Volume 21, Issue 20, p. 942 –943
- DOI: 10.1049/el:19850666
- Type: Article
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–943
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The letter suggests a definition of a nominal characteristic impedance R0 for the dominant mode postulated for lossless rectangular waveguide in order to provide a basis for comparing reflection by waveguide components. The width a, height b and internal corner radius r enter into this defined R0, and the calculated limits of reflection—expressed as return loss normalised to this R0—are presented for some waveguides to British Standard Specifications together with others to tighter tolerances.
Diversity improvement for M-ary noncoherent frequency shift keying in impulsive reverberation noise
- Author(s): A.M. Maras ; H.D. Davidson ; A.G.J. Holt
- Source: Electronics Letters, Volume 21, Issue 20, p. 944 –945
- DOI: 10.1049/el:19850667
- Type: Article
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944
–945
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The improvement in performance of M-ary noncoherent frequency-shift-keying (NCFSK) signals transmitted through a Rayleigh-fading channel computed by additive impulsive reverberation noise; a situation typically arising in active sonar, with diversity is demonstrated via the error probability expression. It is also shown that there is a limitation to diversity improvement.
Experimental application of LD switch modules to 256 Mbit/s optical time switching
- Author(s): T. Matsunaga and M. Ikeda
- Source: Electronics Letters, Volume 21, Issue 20, p. 945 –946
- DOI: 10.1049/el:19850668
- Type: Article
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–946
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The letter proposes an optical time switch using LD switch modules and serial delay lines, and reports on its performance for a 256 Mbit/s 4 × 4 switching system. It can be constructed with fewer delay lines, and needs neither polarisers nor temperature control. Its total insertion loss is 24.8 dB with a loss margin of 4.0 dB.
Characteristics of coupled slow-wave microstrip lines
- Author(s): T.C. Mu ; H. Ogawa ; T. Itoh
- Source: Electronics Letters, Volume 21, Issue 20, p. 946 –947
- DOI: 10.1049/el:19850669
- Type: Article
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The spectral-domain technique has been applied to investigate the characteristics of coupled slow-wave microstrip lines.
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