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Online ISSN 1350-911X Print ISSN 0013-5194

Electronics Letters

Volume 20, Issue 21, 11 October 1984

Volumes & issues:

Volume 20, Issue 21

11 October 1984

Spectral characteristics of a DFB laser under high-speed direct modulation
CW operation of GaInAsP buried ridge structure laser at 1.5 μm grown by LP-MOCVD
Hot electron spectroscopy
Class of recursive sequential regression algorithms
Novel multilayer modulation doped (Al,Ga)As/GaAs structures for self-aligned gate FETs
  • Author(s): N.C. Cirillo ; A. Fraasch ; H. Lee ; L.F. Eastman ; M.S. Shur ; S. Baier
  • Source: Electronics Letters, Volume 20, Issue 21, p. 854 –855
  • DOI:  10.1049/el:19840580
  • Type: Article
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  • p. 854 –855 (2)
    The fabrication of self-aligned gate by ion implantation modulation doped (Al,Ga)As/GaAs field effect transistors (MODFETs) utilising a novel multilayer structure capable of withstanding the high-temperature furnace anneals required for Si implant activation is reported. Typical measured extrinsic transconductances of 175 mS/mm at 300 K and 290 mS/mm at 77 K were achieved on 1.1 μm-gate-length devices. Values of the two-dimensional electron gas saturation velocity of 1.9×107 cm/s at 300 K and 2.7×107 cm/s at 77 K were obtained from an analysis of the FET drain current/voltage characteristics using the charge-control model.
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Low-threshold high-speed 1.55 μm vapour phase transported buried heterostructure lasers (VPTBH)
  • Author(s): T.L. Koch ; L.A. Coldren ; T.J. Bridges ; E.G. Burkhardt ; P.J. Corvini ; B.I. Miller ; D.P. Wilt
  • Source: Electronics Letters, Volume 20, Issue 21, p. 856 –857
  • DOI:  10.1049/el:19840581
  • Type: Article
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  • p. 856 –857 (2)
    A new 1.55 μm InGaAsP buried heterostructure laser has been fabricated using a hydride vapour phase epitaxial regrowth technique. Thresholds as low as 15 mA have been obtained. In addition, improved high-frequency modulation characteristics have been observed resulting from the lowdoped VPE transported material, with 3 dB detected bandwidths out to ∼4.5 GHz.
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Low threshold and low dispersion MOCVD/LPE buried-heterostructure GaAs/GaAlAs lasers
Improved theoretical formula for the relationship between rain attenuation and depolarisation
Heavy metal fluoride glasses with low intrinsic Rayleigh scattering
  • Author(s): J. Schroeder ; V. Tsoukala ; C.O. Staller ; M.A. Stiller ; A. Bruce ; C.T. Moynihan ; J.J. Hutta ; M.J. Suscavage ; M. Drexhage
  • Source: Electronics Letters, Volume 20, Issue 21, p. 860 –862
  • DOI:  10.1049/el:19840584
  • Type: Article
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  • p. 860 –862 (3)
    The results of Rayleigh light scattering measurements in bulk multicomponent fluorozirconate glasses are described. We observe for the first time that such materials may be reproducibly prepared with uniformly low scattering levels throughout their volume. In 13 of the 15 specimens studied, the magnitude of the Rayleigh scattering loss was one-third to one-half that typically observed in fused silica glass.
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Modified state-space filter realisation
Processing of unipolar diodes with electron beams
GaAs field effect transistors prepared on lattice-mismatched InP substrates for monolithic optoelectronic integration
  • Author(s): C.Y. Chen ; A. Antreasyan ; A.Y. Cho ; P.A. Garbinski
  • Source: Electronics Letters, Volume 20, Issue 21, p. 865 –866
  • DOI:  10.1049/el:19840587
  • Type: Article
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  • p. 865 –866 (2)
    We demonstrate for the first time a depletion mode field effect transistor fabricated on GaAs which is grown on top of a lattice-mismatched InP substrate by molecular beam epitaxy. This structure looks promising for the monolithic integration of metal-semiconductor field effect transistors (MESFETs) with photoconductive detectors and other optoelectronic devices. We observe an orientation-dependent surface conductance property. Preliminary experiments reveal a transconductance of about 20 mS/mm.
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Modification of Schwarz approximation
Interpretation of C/V characteristics for heterojunctions and high-low junctions
Analysis of the spectral linewidth of distributed feedback laser diodes
Interference canceller for a single-wavelength bidirectional optical-fibre link
Effect of As4/Ga flux ratio on electrical properties of NID GaAs layers grown by MBE
  • Author(s): A. Saletes ; J. Massies ; G. Neu ; J.P. Contour
  • Source: Electronics Letters, Volume 20, Issue 21, p. 872 –874
  • DOI:  10.1049/el:19840592
  • Type: Article
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  • p. 872 –874 (3)
    The effect of the As4/Ga flux ratio R on NID GaAs layers has been studied when the MBE growth chamber is used without baking after reloading the arsenic cells, in order to increase the productivity of the system. In these conditions a change from p- to n-type is observed when R is varied from 1.8 to 14. Satisfactory p-type material is obtained at R ≤ 3 (p = 2.0 × 1014 cm−3, μ77 K = 6200 cm2 V−1 s−1). The maximum n-type mobility occurs at R = 5.8. Photoluminescence spectroscopy confirms the effect of R on the incorporation of residual impurities.
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Novel calcium-doped yttrium-iron-garnet thermistor bolometer in a planar and continuous bridge configuration
  • Author(s): A. D'Amico ; P. de Gasperis ; F. Giannini ; V. Parisi
  • Source: Electronics Letters, Volume 20, Issue 21, p. 874 –875
  • DOI:  10.1049/el:19840593
  • Type: Article
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  • p. 874 –875 (2)
    A new material, calcium-doped-yttrium iron garnet (Ca:YIG), which proves very promising in room-temperature thermistor bolometer applications, has been used to construct a continuous planar bridge structure which works as a thermistor bolometer detector (YIGTB). Experimental results concerning the electrical response of the bridge as a function of the position of the incident laser light beam are in perfect agreement with those predicted by computer simulation. Since the Ca:YIG has a relatively low thermal capacity and is highly adsorbing from the visible to the infra-red, YIGTB has proved highly responsive and faster than other commercial thermistors.
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Single-chip baseband waveform generator CMOS-LSI for quadrature-type GMSK modulator
  • Author(s): H. Suzuki ; Y. Yamao ; K. Momma
  • Source: Electronics Letters, Volume 20, Issue 21, p. 875 –876
  • DOI:  10.1049/el:19840594
  • Type: Article
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  • p. 875 –876 (2)
    A single-chip baseband waveform generator CMOS-LSI has been fabricated for use in the quadrature-type GMSK modulator, which is suitable for application to digital mobile communications. The LSI employs digital signal processing in realising such functions as Gaussian baseband filtering and phase integration. Digital/analogue convertors and auxiliary circuits, such as an internal-clock generator and carrier frequency adjuster, are also integrated onto the same chip. The LSI operates well below a bit rate of 110 Kbit/s when the power supply voltage is 5 V.
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Inexpensive short-range microwave telemetry transponder
  • Author(s): K.D. Stephan  and  T. Itoh
  • Source: Electronics Letters, Volume 20, Issue 21, p. 877 –878
  • DOI:  10.1049/el:19840595
  • Type: Article
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  • p. 877 –878 (2)
    A microwave transponder is described which is suitable for short-range telemetry applications requiring an inexpensive transmitter. Two antiparallel beam-lead diodes at the terminals of a bow-tie antenna produce double-sideband suppressed-carrier modulation centred about the second harmonic of an externally supplied fundamental carrier. A simple theory predicting performance of the device is confirmed by experiment.
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Error-free external modulation of a single-frequency injection laser at 1.5 Gbit/s using a Ti:LiNbO3 waveguide switch
  • Author(s): S.K. Korotky ; G. Eisenstein ; B.L. Kasper ; R.C. Alferness ; J.J. Veselka ; L.L. Buhl
  • Source: Electronics Letters, Volume 20, Issue 21, p. 878 –879
  • DOI:  10.1049/el:19840596
  • Type: Article
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  • p. 878 –879 (2)
    We have used a packaged high-speed Ti:LiNbO3 directional coupler switch to externally modulate a CW-operated cleaved-coupled-cavity laser oscillating at 1.3 μm wavelength. The performance of the modulator was evaluated by measuring bit error rates for the dominant mode of the laser using a monochromator as a selective bandpass filter. Error-free encoding was achieved for a non-return-to-zero rate of 1.5 Gbit/s. This result and observation of the optical spectrum demonstrate that the external modulation did not degrade the CW characteristics of the laser.
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Low-temperature excess loss of UV-curable acrylate/nylon-coated optical fibres
  • Author(s): H. Itoh ; T. Kimura ; S. Yamakawa
  • Source: Electronics Letters, Volume 20, Issue 21, p. 879 –881
  • DOI:  10.1049/el:19840597
  • Type: Article
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  • p. 879 –881 (3)
    Ultraviolet (UV) radiation curable acrylate/nylon-coated optical fibres show much higher excess loss at low temperatures than silicone/nylon-coated fibres. The difference in low-temperature excess loss between UV-curable acrylate/nylon- and silicone/nylon-coated fibres has been related to the degree of slip between the primary and nylon secondary coating layers during nylon extrusion coating process. The application of a lubricant to the acrylate and nylon interface has been found to be effective in reducing the excess loss at low temperatures.
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High-power SLM operation of 1.3 μm InP/InGaAsP DFB LD with doubly buried heterostructure on p-type InP substrate
Noise-reduction method for ROM/ACC filters
Low-OH-absorption fluoride glass infra-red optical fibres
  • Author(s): G. Mazé ; V. Cardin ; M. Poulain
  • Source: Electronics Letters, Volume 20, Issue 21, p. 884 –885
  • DOI:  10.1049/el:19840600
  • Type: Article
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  • p. 884 –885 (2)
    Ultralow losses of 10−2 to 10−3 dB/km have been predicted in fluoride glass optical fibres between 2 and 4.5 μm. At 2.9 μm, in the central part of this spectral region, the OH− ion presents its fundamental stretching vibration which gives rise to a strong and broad absorption. The attenuation at 2.9 μm in a step-index fluorozirconate glass fibre has been brought down to 58 dB/km, by reducing the OH− concentration in the glass. It is the lowest attenuation yet reported at this wavelength in any optical fibre.
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Measurements of the linewidth of ridge-guide DFB lasers
Improved 2DEG mobility in selectively doped GaAs/N-AlGaAs grown by MOCVD using triethyl organometallic compounds
  • Author(s): N. Kobayashi  and  T. Fukui
  • Source: Electronics Letters, Volume 20, Issue 21, p. 887 –888
  • DOI:  10.1049/el:19840602
  • Type: Article
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  • p. 887 –888 (2)
    In AlGaAs grown by MOCVD, carbon incorporation into the AlGaAs layer is discussed. For AlGaAs grown by trimethyl organometallic compounds, trimethyl aluminium and trimethyl gallium, remarkable carbon incorporation of up to about 1018 cm−3 is observed, although the carbon concentration decreases with the increase of the mole fraction ratio of arsine (AsH3) to III group organometallic compounds, [AsH3]/[III]. On the other hand, the use of triethyl organometallic compounds, triethyl aluminium and triethyl gallium, results in less carbon incorporation (∼1016 cm−3 independently of [AsH3]/[III]. Moreover, in selectively doped GaAs/n-Al0.3Ga0.7As heterostructures, two dimensional electron gas (2DEG) mobility is considerably improved using triethyl organometallic compounds in place of trimethyl organometallics. A 2DEG mobility of 445 000 cm2/V s is obtained for the SD heterostructure with a sheet electron concentration of 5.1 × 1011 cm−2 at 2 K.
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Time-domain behaviour of electric field of an elevated dipole
Worst-month statistics
Excess phase in microstrip DC blocks
Auger recombination in long-wavelength quantum-well lasers
PINFET hybrid optical receivers for 1.2 Gbit/s transmission systems operating at 1.3 and 1.55 μm wavelength
Spectrum of nonuniform samples
Hydrogen quantity generated from optical-fibre coating
Novel GaAs monolithic multistage X–Ku band amplifier
  • Author(s): R. Esfandiari ; Y.K. Chen ; S. Wanuga ; P. Chye ; C. Huang
  • Source: Electronics Letters, Volume 20, Issue 21, p. 898 –899
  • DOI:  10.1049/el:19840610
  • Type: Article
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  • p. 898 –899 (2)
    A novel design approach to a wideband GaAs microwave monolithic amplifier is presented using the principle of feedback and active matching networks. The multistage amplifier utilises a unique biasing circuit which requires only one biasing voltage. A 6–18 GHz multistage amplifier has been demonstrated using the proposed approach. The amplifier has low input/output VSWR, a maximum of 20 dB gain and at least 15 dBm of output power.
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Erratum: Occurrence of a singular Jacobian in filter design

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