Showing papers in "Electronics Letters in 1984"
CNET1
TL;DR: A new N = 2n fast Fourier transform algorithm is presented, which has fewer multiplications and additions than radix 2n, n = 1, 2, 3 algorithms, has the same number of multiplications as the Raderi-Brenner algorithm, but much fewer additions.
Abstract: A new N = 2n fast Fourier transform algorithm is presented, which has fewer multiplications and additions than radix 2n, n = 1, 2, 3 algorithms, has the same number of multiplications as the Raderi-Brenner algorithm, but much fewer additions, and is numerically better conditioned, and is performed ‘in place’ by a repetitive use of a ‘butterfly’-type structure.
412 citations
TL;DR: In this article, an antenna consisting of a resonant dielectric hemisphere on top of a ground plane is investigated, with emphasis on the lowest-order mode that results in efficient radiation in the direction perpendicular to the ground plane.
Abstract: An antenna consisting of a resonant dielectric hemisphere on top of a ground plane is investigated. Calculations of the internal and external fields are made with emphasis on the lowest-order mode that results in efficient radiation in the direction perpendicular to the ground plane. Measured input impedance data are also presented for a practical radiator.
389 citations
TL;DR: In this paper, the inherent connection between frequency deviations and the optical power wave-form of a directly modulated semiconductor laser was derived, providing for the first time a quantitative assessment of inherent optical fiber dispersion penalties.
Abstract: Relations are derived concerning the inherent connection between frequency deviations and the optical power wave-form of a directly modulated semiconductor laser, providing for the first time a quantitative assessment of inherent optical fibre dispersion penalties of directly modulated lasers. The relations also indicate that control of chirp involves only the control of the intensity modulation characteristics and proper current drive of semiconductor lasers. Experimental measurement of FM and IM characteristics of a 1.55 μm DFB laser support the results.
349 citations
TL;DR: In this article, the authors derived analytical expressions for the rapid extraction of solar cell single diode model parameters from experimental data, with less than 5% error for most solar cells.
Abstract: Analytical expressions are derived for the rapid extraction of solar cell single diode model parameters from experimental data. The resulting parameter values are shown to have less than 5% error for most solar cells
348 citations
TL;DR: In this article, some analytical formulas for the parameters of coplanar lines are discussed and validated, and a chart is given for the design of waveguides on GaAs.
Abstract: Some analytical formulas for the parameters of coplanar lines are discussed and validated; a chart is given for the design of coplanar waveguides on GaAs. The formulas discussed here, together with those presented previously by us (1983) represent a suitable set for the design of coplanar lines for hybrid and monolithic MICs (microwave integrated circuits).
223 citations
TL;DR: In this article, the first and second-order statistics of the Rayleigh backscatter signal from a singlemode fiber under quasimonochromatic pulse excitation were derived.
Abstract: The first- and second-order statistics of the Rayleigh back-scatter signal from a single-mode fibre under quasimonochromatic pulse excitation are derived. A fading phenomenon is predicted and observed experimentally.
215 citations
TL;DR: A rough surface analysis of surface plasmon resonance (SPR) is applied to a glass/silver/antigen/antibody/electrolyte multilayer as mentioned in this paper.
Abstract: A rough surface analysis of surface plasmon resonance (SPR) is applied to a glass/silver/antigen/antibody/electrolyte multilayer. Comments are made on the experimental arrangements most appropriate to the development of SPR immunosensors.
194 citations
TL;DR: In this paper, general expressions are derived to estimate transmitter power limitations due to stimulated Raman scattering in wavelength-division-multiplexed optical communication systems with arbitrary number of channels with arbitrary (but equal) channel separation.
Abstract: General expressions are derived to estimate transmitter power limitations due to stimulated Raman scattering in wavelength-division-multiplexed optical communication systems. These results are applicable to systems containing an arbitrary number of channels with arbitrary (but equal) channel separation.
180 citations
TL;DR: In this article, the phase of the corrugations was shifted at the center by a quarter guided-wavelength, which provided a resonance at the Bragg wavelength and stable single-mode oscillation.
Abstract: Fabrication and single-mode laser oscillation were demonstrated for modified DFB lasers where the phase of the corrugations was shifted at the centre by a quarter guided-wavelength and which, in principle, provided a resonance at the Bragg wavelength and stable single-mode oscillation. Phase-shifted corrugations were fabricated using electron-beam lithography.
141 citations
TL;DR: In this article, a bipolar InP transistor is demonstrated which comprises a Zn-diffused base and a transparent conductor widegap emitter made of sputtered cadmium oxide.
Abstract: A novel bipolar InP transistor is demonstrated which comprises a Zn-diffused base and a transparent conductor widegap emitter made of sputtered cadmium oxide. Preliminary current gain was about 10. Owing to its less demanding planar technology the device is assessed to be promising for monolithic integration.
139 citations
TL;DR: In this article, an expression for the probability of error in an optical heterodyne DPSK system, subject to shot noise and quantum phase noise of the optical sources, is derived for the maximum linewidth of the transmit and local optical sources to satisfy a given degradation in optical receiver sensitivity.
Abstract: An expression is derived for the probability of error in an optical heterodyne DPSK system, subject to shot noise and quantum phase noise of the optical sources. Results are given for the maximum linewidth of the transmit and local optical sources to satisfy a given degradation in optical receiver sensitivity.
CNET1
TL;DR: In this article, the transistor effect via ballistic electron transport in the CoSi2 200 A-thick base has been observed and the ballistic mean free path in CoSi 2 obtained (λB 105 A) from the current gain is consistent within 20% with the predicted value (λ Bth 80 A).
Abstract: Epitaxial Si 〈111〉/CoSi2/Si structures have been grown by molecular beam epitaxy. The transistor effect, via ballistic electron transport in the CoSi2 200 A-thick base, has been observed. The ballistic mean free path in CoSi2 obtained (λB 105 A) from the current gain is consistent within 20% with the predicted value (λBth 80 A).
TL;DR: In this paper, Petermann's mathematical definition of spot size using the modal near field and its derivative is proved to be √ 2 times the inverse of the RMS width of the observable modal far field.
Abstract: Petermann's mathematical definition of spot size using the modal near field and its derivative is proved to be √2 times the inverse of the RMS width of the observable modal far field. The theory of fibre optics is given in terms of the transformed field, which determines the far field. Dispersion, splice loss and excitation efficiency are discussed.
TL;DR: In this paper, the authors measured the transport properties of RF sputtered polycrystalline films of indium nitride and reported that the maximum electron mobility is 5000 cm2V-1s-1 at 150 K, and the lowest electron concentrations obtained are 5×1016 cm-3 at 300 K falling to a constant value of 3×1016 in the range 30-150 K.
Abstract: Measurements of the transport properties of RF sputtered polycrystalline films of indium nitride are presented. The maximum electron mobility measured is 5000 cm2V-1s-1 at 150 K, and the lowest electron concentrations obtained are 5×1016 cm-3 at 300 K falling to a constant value of 3×1016 in the range 30-150 K. These results are significantly better than those hitherto reported. The temperature dependence of mobility is attributed to ionised impurity sscattering at low temperatures and space charge scattering at higher temperatures.
TL;DR: A class of block codes is described which exploits the properties of quadrature amplitude modulation signal constellations whose points lie on a square grid and offer coding gains of 3 dB and 4.5 dB.
Abstract: A class of block codes is described which exploits the properties of quadrature amplitude modulation signal constellations whose points lie on a square grid. The simplest codes in the class have block lengths 4 and 8 and offer coding gains of 3 dB and 4.5 dB, respectively.
TL;DR: In this article, a CCII+ current conveyor circuit implementation was proposed to improve the performance of the CCII circuit and is also more suitable for monolithic fabrication than previous CCII circuits.
Abstract: Wideband precision current conveyor performance can be obtained by adapting an approach previously developed for current convertors. The proposed circuit implementation of a CCII+ current conveyor significantly exceeds the performance of all previous conveyor circuit formulations and is also more suitable for monolithic fabrication.
TL;DR: In this paper, a GaAs with a mirror-like surface is grown by MOCVD on an Si substrate using an AlP, AlGaP, GaP/GaAs 0.5P0.5 super-lattice and GaAs0.6P0/GaA superlattices as intermediate layers, and the photoluminescence intensity is found to be about 56% of that of the GaAs substrate.
Abstract: GaAs with a mirror-like surface is grown by MOCVD on an Si substrate using an AlP, AlGaP, GaP/GaAs0.5P0.5 super-lattice and GaAs0.5P0.5/GaAs superlattice as intermediate layers. The photoluminescence intensity is found to be about 56% of that of a GaAs substrate grown under the same conditions and is one order of magnitude higher than that grown on a Ge-coated Si substrate, in spite of the early stage of the experiment.
TL;DR: In this article, a λ/4-phase shift in the first-order corrugations formed on an InP substrate was confirmed through SEM views and diffracted beam patterns.
Abstract: λ/4-shifted InGaAsP/InP DFB lasers were fabricated by a novel method, that is, simultaneous holographic exposure of positive and negative photoresists. The λ/4-phase-shift in the first-order corrugations formed on an InP substrate was confirmed through SEM views and diffracted beam patterns. A strong resonance peak below the threshold and single-wavelength operation above it at the Bragg wavelength were observed.
TL;DR: In this article, the authors describe a method of achieving a fiber optic hydrophone array using a single laser source and detector, which consists of several sections of fibre which are spliced together with retroreflective splices and form part of a pulsed Michelson interferometer.
Abstract: The letter describes a new method of achieving a fibre optic hydrophone array using a single laser source and detector. The array consists of several sections of fibre which are spliced together with retroreflective splices and form part of a pulsed Michelson interferometer.
TL;DR: In this paper, a single-phase unidirectional transducer utilizing the difference between excitation and reflection positions caused by the floating electrodes of open and short metal strips inserted into the interdigital transducers within a half wavelength is described.
Abstract: A new single-phase unidirectional transducer utilising the difference between excitation and reflection positions caused by the floating electrodes of open and short metal strips inserted into the interdigital transducer within a half wavelength is described.
TL;DR: In this article, the effect of modulation-induced laser wavelength shifts on optical transmission through dispersive fibres is shown to be a serious limiting factor at bit rates greater than 1 Gbit/s.
Abstract: The effect of modulation-induced laser wavelength shifts on optical transmission through dispersive fibres is shown to be a serious limiting factor at bit rates greater than 1 Gbit/s. Wavelength excursions with magnitudes as large as 6 A are seen to occur in single-frequency lasers (C3 and DFB) during a transition from one power level to another. The wavelength shifts briefly toward shorter wavelengths and then back to the equilibrium value during turn-on and toward longer wavelengths and back during turn-off. These excursions, which are well explained by a model in which the carrier density is temporarily driven out of equilibrium by a change in injection current, last for hundreds of picoseconds or about one half of the relaxation resonance period. This time-dependent behaviour gives rise to a dramatic degradation of system performance with increasing bit rate.
TL;DR: In this article, the optical output of an interferometer is projected onto three (or more) polarisation states, detected and combined, and the maximum variation in signal and in signal/noise ratio is 6 dB.
Abstract: A technique is described in which polarisation fading of the output of an interferometer is eliminated. The optical output of the interferometer is projected onto three (or more) polarisation states, detected and combined. The maximum variation in signal and in signal/noise ratio is 6 dB.
TL;DR: In this paper, the authors describe a configuration of the polarimetric sensor which uses two equal lengths of polarisation-maintaining fiber spliced together with their major polarisation axes orthogonal.
Abstract: The letter describes a novel configuration of the polarimetric sensor which uses two equal lengths of polarisation-maintaining fibre spliced together with their major polarisation axes orthogonal The result is a differential sensor which is compensated for common-mode temperature and isotropic pressure changes, and may be used with semiconductor laser sources without the problems of phase noise which can arise in the normal polarimetric sensor
TL;DR: In this article, a phase-swept pseudo-heterodyne scheme suitable for use with all-fibre versions of the fibre gyroscope is presented, which employs a sinusoidal phase modulation via a piezoelectric fibre stretcher in combination with selective detector gating.
Abstract: The results of a preliminary investigation of a phase-swept pseudo-heterodyne scheme suitable for use with all-fibre versions of the fibre gyroscope are presented. The output carrier, which is phase-modulated by the Sagnac shift, is generated by employing a sinusoidal phase modulation via a piezoelectric fibre stretcher in combination with selective detector gating
TL;DR: In this article, a switch-capacitor stage which is free from the effects of op-amp DC offset voltage is described and the op-amps used in the stage need not slew between the desired output voltage and the offset voltage as in previously described offset-free circuits.
Abstract: Novel switched-capacitor stages which are free from the effects of op-amp DC offset voltage are described. The op-amps used in the stage need not slew between the desired output voltage and the offset voltage as in previously described offset-free circuits. The use of the new scheme in general applications is also discussed.
TL;DR: In this article, a lateral resurfed COMFET structure is proposed, where the conductivity of the drift region of the device is modulated as in the case of vertical COMFLET, and the maximum operating current and switching speed are expected to be several times that of the vertical structure.
Abstract: A lateral resurfed COMFET structure is proposed. The conductivity of the drift region of the device is modulated as in the case of vertical COMFET. However, the maximum operating current and switching speed are expected to be several times that of the vertical structure because of the collection of excess minority carriers by the p?-substrate and the narrow width of the n? epitaxial layer.
TL;DR: In this article, the six-port technique developed at microwave frequencies was used to measure the relative phase and amplitude of optical signals with approximately 130 photons energy at 633 nm, and applications include phase measurements in coherent optical communication systems.
Abstract: ‘Six-port’ techniques developed at microwave frequencies have been used to measure the relative phase and amplitude of optical signals with approximately 130 photons energy at 633 nm. Applications include phase measurements in coherent optical communication systems.
TL;DR: Measurements of time delay spread of wideband 850 MHz digital radio signals due to multipath propagation within a large building are described, showing a median RMS time delay Spread of 125 ns and a worst case of 250 ns.
Abstract: Measurements of time delay spread of wideband 850 MHz digital radio signals due to multipath propagation within a large building are described. These measurements show a median RMS time delay spread of 125 ns and a worst case of 250 ns. Consequently, signalling rates above 400 kHz may not be feasible.
TL;DR: In this article, the authors have successfully grown GaAs/AlGaAs MODFETs directly on silicon substrates by molecular beam epitaxy, which has great implications with regard to the monolithic integration of III-V and Si technology.
Abstract: We have successfully grown GaAs/AlGaAs MODFETs directly on silicon substrates by molecular beam epitaxy. We have found that an orientation slightly off (100) is well suited for the growth of GaAs/AlGaAs on silicon substrates. MODFETs fabricated from layers grown on Si had transconductances of 170 mS/mm at room temperature and exhibited no looping. When cooled to 77 K, the transconductance rose to 275 mS/mm. Hall mobilities of 51000 and 38000 cm2/Vs were obtained at 10 and 77 K, respectively, with sheet electron densities of 8.30 × 1011 cm−2 in both cases. These results clearly demonstrate that device quality GaAs/AlGaAs is obtainable directly on Si substrates which has great implications with regard to the monolithic integration of III–V and Si technology.
TL;DR: In this article, the effect of a mirror facet at the end of the corrugation of a DFB laser was analyzed and the structure with no reflection was found to be the most promising.
Abstract: Wavelength selectivity of a quarter-wave-shifted DFB laser is analysed taking into account the effect of a mirror facet at the end of the corrugation. The structure with no reflection is found to be the most promising. The effect of a cleaved facet at an end is not serious as long as KL is as large as 3-5.