Online ISSN
1350-911X
Print ISSN
0013-5194
Electronics Letters
Volume 25, Issue 9, 27 April 1989
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Volume 25, Issue 9
27 April 1989
Novel ion-assisted antireflection coatings for lithium niobate devices
- Author(s): J. Davidson and I. Reid
- Source: Electronics Letters, Volume 25, Issue 9, p. 557 –558
- DOI: 10.1049/el:19890380
- Type: Article
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A technique for producing single-layer antireflection coatings on lithium niobate is described, based on ion-assisted deposition of magnesium fluoride and silicon dioxide. Measuremenu show a lowest device reflectivity of −42dB, at 1.55μm, using a silicon dioxide coating.
5.5 GHz multiple quantum wellreflection modulator
- Author(s): G.D. Boyd ; J.E. Bowers ; C.E. Soccolich ; D.A.B. Miller ; D.S. Chemla ; L.M.F. Chirovsky ; A.C. Gossard ; J.H. English
- Source: Electronics Letters, Volume 25, Issue 9, p. 558 –560
- DOI: 10.1049/el:19890381
- Type: Article
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We report the fabrication and operation of a high-speed reflection modulator using the quantum-confined Stark effect in GaAs quantum wells grown over a dielectric mirror. The modulator has a 5.5 GHz 3 dB response.
Correlation of tunnelling currents and tunable luminescence in selectively diffused nipi LEDs
- Author(s): D.E. Ackley ; J. Mantz ; H. Lee ; N. Nouri ; R. Cheponis ; C.-L. Shieh
- Source: Electronics Letters, Volume 25, Issue 9, p. 560 –561
- DOI: 10.1049/el:19890382
- Type: Article
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Measurements of the current/voltage characteristics and electroluminescence spectra of nipi LEDs with selectively diffused contacts have been performed over the temperature range 3-300 K. Good correlation has been observed between the forward characteristics of the diodes and the tuning of the electroluminescence. Analysis of the I/V characteristics indicates that the recombination occurs by electron tunnelling through the parabolic potential barriers.
Accurate analytical approximations for error function and its integral
- Author(s): P. Van Halen
- Source: Electronics Letters, Volume 25, Issue 9, p. 561 –563
- DOI: 10.1049/el:19890383
- Type: Article
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Analytical expressions for the error function and the integral of the error function, which can be used in the calculation of electric field and potential distribution in semiconductor junctions with a Gaussian doping profile, are presented. For both functions, the complete x-interval, ranging from 0 to infinity, is handled with a single expression. The absolute accuracy of the analytical expressions for all x-values is better than ±1.6×10−9for the error function and better than ±3.7×10−8 for the integral of the error function.
Picosecond pulse amplification by electrically pulsed semiconductor optical amplifiers
- Author(s): P.B. Hansen ; G. Eisenstein ; J.M. Wiesenfeld ; R.S. Tucker ; G. Raybon
- Source: Electronics Letters, Volume 25, Issue 9, p. 563 –565
- DOI: 10.1049/el:19890384
- Type: Article
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–565
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We report time-resolved gain and noise spectra measurements in an electrically pulsed travelling-wave optical amplifier. We demonstrate a modest (60Å) blue shift in the gain spectrum and high (25 dB) gain in a 250μmlong amplifier driven by a 1 GHz, 60 ps pulse train.
Bulk silicon technology for complementary MESFETs
- Author(s): U. Magnusson ; J. Tiren ; A. Söderbärg ; M. Rosling ; Ö. Grelsson ; H. Bleichner ; J.O. Nylander ; S. Berg
- Source: Electronics Letters, Volume 25, Issue 9, p. 565 –566
- DOI: 10.1049/el:19890385
- Type: Article
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A technology for fabrication of complementary silicon MESFETs on bulk silicon substrates has been developed. The technology is similar to CMOS technology, and utilises n-silicon substrates. P-wells are used for the n-channel devices. Device isolation was achieved by trench etching. The silicidcs of Er and Pt were used as gate Schottky contacts. P-and n-channel characteristics are presented together with subthreshold behaviour and preliminary results regarding radiation hardness. Also, results from two-dimensional simulations of the devices are presented.
High-contrast reflection modulation at normal incidence in asymmetric multiple quantum well Fabry-Perot structure
- Author(s): M. Whitehead and G. Parry
- Source: Electronics Letters, Volume 25, Issue 9, p. 566 –568
- DOI: 10.1049/el:19890386
- Type: Article
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We have modelled the properties of a multiple quantum well pin diode optical modulator with the natural semiconductor reflectivity (R ≈ 0.3) at its front surface and a high reflector (R ≈ 0.95), such as an integrated semiconductor quarterwave stack, at the back. By using resonant electroabsorption, rather than electrorefraction, our calculations show that it is possible to achieve contrast ratios of over 200, with less than 3dB insertion loss.
Highly uniform, high quantum efficiency GaInAsSb/AlGaAsSb double heterostructure lasers emitting at 2.2 μm
- Author(s): J.L. Zyskind ; J.C. Dewinter ; C.A. Burrus ; J.C. Centanni ; A.G. Dentai ; M.A. Pollack
- Source: Electronics Letters, Volume 25, Issue 9, p. 568 –570
- DOI: 10.1049/el:19890387
- Type: Article
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GaInAsSb/AlGaAsSb double heterostructure lasers with low pulsed threshold current density were grown previously by liquid-phase epitaxy using a complicated five-layer structure to relieve the strain arising from graded cladding layers. Double heterostructures have now been grown over a narrower temperature range to minimise this grading. These simpler three-layer DH lasers have high room-temperature quantum efficiencies (5.4% per facet) and low broad-area threshold current densities (2.6 kA/cm2) which are uniform from chip to chip.
Transmission properties of some hollow glass waveguides at 10.6 μm wavelength
- Author(s): C.A. Worrell
- Source: Electronics Letters, Volume 25, Issue 9, p. 570 –571
- DOI: 10.1049/el:19890388
- Type: Article
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The CO2 laser transmission properties of two hollow glass waveguides of different composition are reported. The results for both straight and bent guide clearly demonstrate the reductions in waveguide loss with a glass of refractive index of less than unity at 10.6 μm wavelength.
Deadlock-free window algorithm with limited splitting for multiple access channels
- Author(s): E. Choi and M. Kim
- Source: Electronics Letters, Volume 25, Issue 9, p. 571 –572
- DOI: 10.1049/el:19890389
- Type: Article
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By limiting the total number of splitting windows and using a probabilistic retransmission scheme, we propose a windowalgorithm to be deadlock-free from noisy feedback and simultaneous arrival of messages. The performance of the limited splitting algorithm is evaluated with respect to the maximal throughput under a Poisson infinite-user model.
Nearly ideal enhanced barrier height Schottky contacts to n-InP for MESFET applications
- Author(s): A.A. Iliadis
- Source: Electronics Letters, Volume 25, Issue 9, p. 572 –574
- DOI: 10.1049/el:19890390
- Type: Article
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We report the substantial enhancement of the Schottky barrier height of n-InP, using a new surface passivation process. Au contacts on the passivated surface resulted in nearly ideal Schottky diodes with barrier heights as large as 0.83 eV, ideality factors between 1.02 and 1.17 and high breakdown voltages. The passivation is found to promote the formation of a phosphorus oxide at the interface, which is believed to be responsible for the enhancement of the barrier height. The highquality of the contacts makes them ideal for InP MESFET gate electrodes.
16-channel optical FDM distribution/transmission experiment utilising multichannel frequency stabiliser and waveguide frequency selection switch
- Author(s): H. Toba ; K. Oda ; K. Nosu ; N. Takato
- Source: Electronics Letters, Volume 25, Issue 9, p. 574 –576
- DOI: 10.1049/el:19890391
- Type: Article
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A 16-channel, 622 Mbit/s optical FDM distribution/transmission system experiment is demonstrated for a fibre length of 13 km. The feasibility of a multicarrier frequency stabiliser and waveguide frequency selection switch for 5 GHz frequency intervals is verified.
Phase error free linc modulator
- Author(s): S. Tomisato ; K. Chiba ; K. Murota
- Source: Electronics Letters, Volume 25, Issue 9, p. 576 –577
- DOI: 10.1049/el:19890392
- Type: Article
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A new technique for linear amplification with nonlinear components (LINC) is described. LINC implementation is thought to be very difficult because of its sensitivity to phase error caused by the difference in electrical length between two power amplifier branches. The allowable limit of phase error for achieving the 60 dB suppression of the adjacent channel interference (ACI) power is estimated for roll-off bandlimited offset QPSK (OQPSK). Then, a compensating method for this phase error is presented. By using the proposed method, sufficient out-of-band spectrum suppression for mobile radio application is obtained. An output power of 7.5 W and a power efficiency of 21% are experimentally confirmed.
Key changeable ID-based cryptosystem
- Author(s): K. Kurosawa
- Source: Electronics Letters, Volume 25, Issue 9, p. 577 –578
- DOI: 10.1049/el:19890393
- Type: Article
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ID-based public key crypt osystems and ID-based signature systems are proposed. Users can change their key parameters by themselves easily with no help from the centre. There is no threat of user conspiracy.
Novel strained quantum well laser grown by MOVPE
- Author(s): J.N. Tothili ; L. Westbrook ; C.B. Hatch ; J.H. Wilkie
- Source: Electronics Letters, Volume 25, Issue 9, p. 578 –580
- DOI: 10.1049/el:19890394
- Type: Article
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Strained-layer broad-area lasers have been grown by MOVPE. The structures contain 3.5nm-wide Ga0.3In0.7As quantum wells. They emit close to 1.5μm and have been made to lase under current injection. These structures were compared with similar lasers containing unstrained 7.0n m-wide Ga0.47In0.53As quantum wells also emitting at 1.5μ m. No improvement has been found in Jth (933 cm−2) or T0 (47 K) in the case of the strained structure, despite the expected band structure modification.
MOCVD-grown AlInAs/GaInAs MODFET with drain currents higher than 1.3 Am/m
- Author(s): W.-P. Hong ; G.-K. Chang ; R. Bhat ; W. Chan ; B. van der Gaag ; P. Lin ; J.H. Abeles
- Source: Electronics Letters, Volume 25, Issue 9, p. 580 –581
- DOI: 10.1049/el:19890395
- Type: Article
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Very high-density and high-mobility AlInAs/GaInAs modulation-doped heterostructures have been successfully grown by low-pressure MOCVD. FETs, having gate lengths of 0.25 μm, fabricated from these heterostructures show transconductances as high as 700mS/mm, and drain saturation currents in excess of l. 3mA/mm at Vgs=0V This current density is among the highest yet reported for FETs grown by any technique. The extracted current-gain cutoff frequency is 78 GHz.
Transient analysis of ferrite twin-toroid phase shifter by spatial network method
- Author(s): N.K. Kukutsu ; N. Yoshida ; I. Fukai
- Source: Electronics Letters, Volume 25, Issue 9, p. 581 –583
- DOI: 10.1049/el:19890396
- Type: Article
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In the letter the transient characteristics of electromagnetic fields caused by changing the direction of remanentmagnetisation in a twin-toroid phase shifter is simulated by the spatial network method. The time responses of the field and its instantaneous distributions are presented.
Monolithic integration of pseudomorphic power and low-noise HEMTs
- Author(s): P. Saunier ; H.Q. Tserng ; H.D. Shih ; K. Bradshaw
- Source: Electronics Letters, Volume 25, Issue 9, p. 583 –584
- DOI: 10.1049/el:19890397
- Type: Article
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Monolithic integration of pseudomorphic power and low-noise high electron mobility transistors (HEMTs) on a GaAs substrate has been demonstrated using specially designed multiple epitaxial layers. MBE-grown layers with three heterojunctions were selectively recessed to provide optimum structures for low-noise and power operations. At 18 GHz, a record power-added efficiency of 59% with 8dB gain and 0.4W/mm power density was obtained for the power HEMT. The low-noise device from the same slice achieved a noise figure of ldB with 9dB associated gain at the same frequency.
Novel multiple reference voltage generation scheme for pipeline A/D conversion
- Author(s): K.R. Lakshmikumar and K. Nagaraj
- Source: Electronics Letters, Volume 25, Issue 9, p. 584 –586
- DOI: 10.1049/el:19890398
- Type: Article
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A novel scheme for generating multiple reference voltages for pipeline A/D conversion is proposed. The basic idea is to develop the required reference voltages by summing the voltages from two reference voltage banks. This scheme has potential for high-speed conversion. Further, the architecture of the resistor network which forms the two voltage banks, offers a wide trade-off in power dissipation and speed while requiring a small chip area.
Comparison of 1-bit adaptive quantisers for speech coding
- Author(s): S.C. Hall and H.S. Bradlow
- Source: Electronics Letters, Volume 25, Issue 9, p. 586 –588
- DOI: 10.1049/el:19890399
- Type: Article
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A 1-bit version of the recently proposed generalised hybrid adaptive quantiser (GHAQ) is compared with two other 1-bitadaptive quantisers, in terms of the signal-to-noise ratio obtained when coding speech in delta modulators. The GHAQ is found to have a clear advantage, particularly when the speech is acquired by a telephone microphone. It is also shown that the optimum coefficients of the predictor can be influenced substantially by the design of the adaptive quantiser, and a technique for finding suitable coefficients in this context is described.
560 Mbit/s optical PSK heterodyne detection using carrier recovery
- Author(s): S. Watanabe ; T. Chikama ; T. Naito ; H. Kuwahara
- Source: Electronics Letters, Volume 25, Issue 9, p. 588 –590
- DOI: 10.1049/el:19890400
- Type: Article
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An optical PSK heterodyne synchronous detection experiment was performed at a bit rate of 560 Mbit/s using carrier recovery in the IF stage. A receiver sensitivity of −51.6 dBm was achieved, and the power penalty due to the phase noise of the laser diodes was suppressed to less than that of DPSK.
Photoluminescence in InP hydrogenated by plasma exposure
- Author(s): T. Sugino ; A. Boonyasirikool ; J.S. Shirafuji ; H. Hashimoto
- Source: Electronics Letters, Volume 25, Issue 9, p. 590 –591
- DOI: 10.1049/el:19890401
- Type: Article
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Hydrogenation of an InP surface has been achieved by hydrogen plasma. Exposure in the limited temperature range 95–100°C gives rise to a remarkable enhancement of the photoluminescence (PL) intensity by a factor of 5.4 compared with that of unexposed InP. On the other hand, a reduction in the PL intensity occurs at temperatures a little higher than 100°C which leads to surface damage owing to preferential dissociation of phosphorus from the surface of InP. It is confirmed by secondary ion mass spectroscopy (SIMS) that hydrogen with concentration of 1 ×1018 cm−3 diffuses into the bulk InP down to a depth of 300 nm.
Circuit models for frequency modulation response of semiconductor lasers
- Author(s): W.H. Hong ; J.H. So ; H.K. Park ; J.G. McInerney
- Source: Electronics Letters, Volume 25, Issue 9, p. 591 –592
- DOI: 10.1049/el:19890402
- Type: Article
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The letter describes a new circuit modelling technique for the directly frequency-modulated CSP semiconductor laser. In particular, this model accounts not only for the carrier density but also the temperature effects. Predictions from this model are compared with other published results of sinusoidal frequency modulation in the range DC-3GHz and show good agreement.
Continuous-wave oscillation of holmium-doped silica fibre laser
- Author(s): D.C. Hanna ; R.M. Percival ; R.G. Smart ; J.E. Townsend ; A.C. Tropper
- Source: Electronics Letters, Volume 25, Issue 9, p. 593 –594
- DOI: 10.1049/el:19890403
- Type: Article
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Laser emission at 2.04μm has been observed in a silica fibre doped with Ho3+.When pumped with an argon laser at 457.9 nm an absorbed threshold power of 46 mW and a slopeefficiency of 1.7% were measured.
Mutual signal gain saturation in Er3+-doped fibre amplifier around 1.54 μm wavelength
- Author(s): K. Inoue ; H. Toba ; N. Shibata ; K. Iwatsuki ; A. Takada ; M. Shimizu
- Source: Electronics Letters, Volume 25, Issue 9, p. 594 –595
- DOI: 10.1049/el:19890404
- Type: Article
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Signal gain saturation characteristics of a 1.48 μm wavelength LD pumped Er3+-doped fibre amplifier are experimentally investigated for two signal channels amplifiedaround the gain peak wavelengths of 1.535 μm and 1.551 μm. The degree of gain saturation is uniquely determined by thetotal output power when the signal wavelengths are closely positioned. This feature is not suited to two-channel amplification for widely spaced wavelengths.
11 Gbit/s optical transmission experiment using 1540nm DFB laser with non-return-to-zero modulation and pin/HEMT receiver
- Author(s): J.L. Gimlett ; M.Z. Iqbal ; J. Young ; L. Curtis ; R. Spicer ; N.K. Cheung ; S. Tsuji
- Source: Electronics Letters, Volume 25, Issue 9, p. 596 –597
- DOI: 10.1049/el:19890405
- Type: Article
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An 11 Gbit/s optical transmission experiment, employing a 1540nm distributed feedback (DFB) laser modulated with non-retum-to-zero signal format and an ultrawideband pin/ HEMT receiver, is described. This is the highest data rate transmission experiment reported to date using a directly modulated DFB laser. A span of 81 km of dispersion shiftedfibre was employed resulting in a record bit rate-distance product of 890 Gbit/s km, with no observable penalty due to insertion of the fibre.
Two-dimensional, coherent y-coupled grating surface-emitting laser arrays
- Author(s): G.A. Evans ; N.W. Carlson ; J.M. Hammer ; M. Lurie ; J.K. Butler ; J. Connolly ; L.A. Carr ; F.Z. Hawrylo ; E.A. James ; C.J. Kaiser ; J.B. Kirk ; W.F. Reichert
- Source: Electronics Letters, Volume 25, Issue 9, p. 597 –599
- DOI: 10.1049/el:19890406
- Type: Article
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Two-dimensional, coherent, grating surface-emitting AlGaAs laser arrays consisting of forty (4×10)active elements have been fabricated with a multiple quantum well structure. The elements of the array are index-guided ridge lasers, connected laterally by Y-branches and coupled longitudinally with passive ridge waveguides containing second-order distributed Bragg reflectors.
Transverse resonance method for analysing finlines
- Author(s): G.X. Chang
- Source: Electronics Letters, Volume 25, Issue 9, p. 599 –600
- DOI: 10.1049/el:19890407
- Type: Article
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A new equivalent circuit model and Cohn's expression for discontinuity susceptance are introduced to analysing finlines. Transcendental equations are given from the transverse resonance condition. The numerical results for normalised cut-off wavelength are compared with previous theoretical and measured values.
Nondestructive measuring technique for misaligned angle in polarisation-maintaining fibre coupler
- Author(s): M. Takahashi ; S. Tai ; K. Kyuma
- Source: Electronics Letters, Volume 25, Issue 9, p. 600 –602
- DOI: 10.1049/el:19890408
- Type: Article
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It is first shown that polarisation coupling gives rise to a large deformation of the resonant curve of a fibre-optic ring resonator. The misaligned angle between the principal axes in the polarisation-maintaining fibre coupler, which is the dominant origin of polarisation coupling, was measured by observing the deformed resonant curve.
Field measurement of fusion splice loss using pulse reflection method
- Author(s): J. Peacock ; J. Scarfe ; J. Reid ; S.R. Mallinson
- Source: Electronics Letters, Volume 25, Issue 9, p. 602 –603
- DOI: 10.1049/el:19890409
- Type: Article
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The letter describes a field experiment to determine the feasibility of using a pulse reflection method for single-ended splice loss evaluation using an OTDR. Results show that although small errors are obtained in the splice measurement (directly related to the level of reflection caused by the OTDR) the method is reasonably accurate and practical for use on short-haul optical systems.
16 Gbit/s, 70 km pulse transmission by simultaneous dispersion and loss compensation with 1.5 μm optical amplifiers
- Author(s): N.A. Olsson ; G.P. Agrawal ; K.W. Wecht
- Source: Electronics Letters, Volume 25, Issue 9, p. 603 –605
- DOI: 10.1049/el:19890410
- Type: Article
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A scheme for using semiconductor laser amplifiers for simultaneous compensation of both the fibre loss and the fibre dispersion in the 1.5 μm region is proposed and demonstrated. Experimentally, we demonstrate propagation of 16 Gbit/s pulses over 70 km of non-dispersion-shifted fibre at 1.53 μm wavelength. This distance is four times longer than the fundamental dispersion limit for transform-limited pulses.
Spectral index method applied to coupled rib waveguides
- Author(s): S.V. Burke
- Source: Electronics Letters, Volume 25, Issue 9, p. 605 –606
- DOI: 10.1049/el:19890411
- Type: Article
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The spectral index method is applied to closely coupled rib waveguides. Analytical expressions in terms of the propagation constant β are given for symmetric and antisymmetric polarised modes. The calculated coupling lengths are in excellent agreement with those obtained by mainframe programs.
Monolithic wavelength-flattened 1×7 single-mode fused coupler
- Author(s): D.B. Mortimore and J.W. Arkwright
- Source: Electronics Letters, Volume 25, Issue 9, p. 606 –607
- DOI: 10.1049/el:19890412
- Type: Article
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The operating principle, fabrication and performance of a wavelength-flattened 1×7 single-mode fused coupler is reported. The device has low excess loss (<0.3 dB) together with good coupling uniformity (<1% standard deviation) at both 1.3 and 1.53 μm.
Second-and third-order sensitivities of microwave circuits
- Author(s): T. Redon and G. Vasilescu
- Source: Electronics Letters, Volume 25, Issue 9, p. 607 –609
- DOI: 10.1049/el:19890413
- Type: Article
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The letter considers the computation of the second-and third-order sensitivities of microwave circuits, which opens the field to optimisation via Newton's method. Definitions of higher-order relative sensitivities are introduced, together with a criterion to select ‘hot’ sensitivities.
Npn and pnp GaInP/GaAs heterojunction bipolar transistors grown by MOCVD
- Author(s): H. Kawai ; T. Kobayashi ; F. Nakamura ; K. Taira
- Source: Electronics Letters, Volume 25, Issue 9, p. 609 –610
- DOI: 10.1049/el:19890414
- Type: Article
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Both Npn and Pnp heterojunction bipolar transistors were fabricated using the GaInP/GaAs system for the first time by MOCVD to investigate the band lineup of the GaInP/GaAs system. By comparing the collector current, current gain and offset voltage of the Npn and the Pnp HBTs, most of the bandgap difference was found to be in the valence band.
AlGaAs/GaAs HBT with GaInAs cap layer fabricated by multiple-self-alignment process using one mask
- Author(s): Y. Ota ; T. Hirose ; M. Yanagihara ; A. Ryoji ; T. Kato ; M. Inada
- Source: Electronics Letters, Volume 25, Issue 9, p. 610 –612
- DOI: 10.1049/el:19890415
- Type: Article
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An AlGaAs/GaAs HBT has been fabricated by introducing an n+-GaInAs cap layer to reduce the emitter contact resistivity and optimising a multiple self-alignment process using one mask. The HBT has a good high-frequency performance of fT= 82GHz and fmax= 120GHz
Spectrum efficiency for multitransmitter simulcasting in land mobile radio
- Author(s): S. Ogose and T. Hattori
- Source: Electronics Letters, Volume 25, Issue 9, p. 612 –613
- DOI: 10.1049/el:19890416
- Type: Article
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Multitransmitter simulcasting is one of the most useful techniques for transmitting control or paging signals in land mobile radio communications. In this letter, the spectrum efficiency for a practical zone structure is evaluated and compared with that for sequential transmissions.
Cache memory for Prolog stack
- Author(s): B. Lazzerini and L. Lopriore
- Source: Electronics Letters, Volume 25, Issue 9, p. 613 –615
- DOI: 10.1049/el:19890417
- Type: Article
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By exploiting the memory behaviour of Prolog programs, the cache architecture presented in this letter achieves a considerable improvement over traditional cache architectures in terms of both performance and hardware complexity.
Solid-state porosity characterisation: photothermal approach
- Author(s): Y.V. Gulyaev ; A.I. Morozov ; V.Y. Raevskii
- Source: Electronics Letters, Volume 25, Issue 9, p. 615 –616
- DOI: 10.1049/el:19890418
- Type: Article
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615
–616
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A novel photothermal method for the characterisation of porous ceramics is presented. The method enables the measurement of bulk porosity in the concentration range 5–10% and yields information on the pore structure.
DQDB simulation and MAC protocol analysis
- Author(s): A. Myles
- Source: Electronics Letters, Volume 25, Issue 9, p. 616 –618
- DOI: 10.1049/el:19890419
- Type: Article
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616
–618
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The distributed queue dual bus (DQDB) metropolitan area network (MAN) is currently being standardised by IEEE 802.6. This letter reports on a characteristic of the DQDB MAC protocol, found using simulation, which causes the end stations to experience higher delays than the middle stations under certain conditions. One mechanism is described to explain the phenomenon along with a modification to improve the protocol's behaviour.
Linear pulse distortion effects in applications of semiconductor optical amplifiers to local network
- Author(s): L.A. Zenteno
- Source: Electronics Letters, Volume 25, Issue 9, p. 618 –619
- DOI: 10.1049/el:19890420
- Type: Article
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p.
618
–619
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It is shown that residual facet reflectivity in travelling-wave semiconductor optical amplifiers causes cumulative pulse broadening and distortion, hence limiting the maximum number of amplifiers that may be reliably used in a local network. For a TDM network, closed-form expressions are derived for this number in terms of bit rate and amplifier and pulse parameters.
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