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Online ISSN 1350-911X Print ISSN 0013-5194

Electronics Letters

Volume 21, Issue 19, 12 September 1985

Volumes & issues:

Volume 21, Issue 19

12 September 1985

Automatic manufacture of polished single-mode-fibre directional coupler
Frequency and polarisation scaling of microwave attenuation during rainfall
Millimetre-wave dielectric waveguide ferrite phase shifter with longitudinal magnetisation
Wide-margin Josephson-junction A/D convertor using redundant coding
Fast-fading characterisation in urban mobile propagation at 855 MHz in Paris
1.55 μm InGaAsP low-threshold buried-crescent injection laser
  • Author(s): W.H. Cheng ; L. Perillo ; S. Forouhar ; O.K. Kim ; C.L. Jiang ; S.K. Sheem
  • Source: Electronics Letters, Volume 21, Issue 19, p. 832 –834
  • DOI:  10.1049/el:19850588
  • Type: Article
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  • p. 832 –834 (3)
    Fabrication of 1.55 μm InGaAsP buried-crescent (BC) injection lasers with a p-n-p-n blocking structure is described. The BC lasers exhibit a threshold current as low as 14 mA at 25°C, very high yield, output power more than 10 mW and high-temperature operation up to 80°C. These BC lasers have continued to operate in stable CW mode at 50°C for more than 1000 h. The lifetime of the 1.55 μm InGaAsP lasers at 50°C is estimated to exceed about 2.5 × 104 h.
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Design of error tolerance of a phased array
  • Author(s): J.K. Hsiao
  • Source: Electronics Letters, Volume 21, Issue 19, p. 834 –836
  • DOI:  10.1049/el:19850589
  • Type: Article
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  • p. 834 –836 (3)
    In the letter we present a set of universal probability curves that relate the array error tolerance, illumination function, achievable sidelobe level and the designed sidelobe level. We show that this set of probability curves can be used to find a lower designed sidelobe level to achieve a better error tolerance. The relations of array directivity gain and beamwidth with respect to illumination function are also discussed. These parameters can be conveniently used for this design procedure without detailed knowledge of the array illumination.
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Applied potential tomography (APT) for noninvasive thermal imaging during hyperthermia treatment
GaInAs PIN photodiodes grown by atmospheric-pressure MOVPE
  • Author(s): A.W. Nelson ; S. Wong ; S. Ritchie ; S.K. Sargood
  • Source: Electronics Letters, Volume 21, Issue 19, p. 838 –840
  • DOI:  10.1049/el:19850591
  • Type: Article
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  • p. 838 –840 (3)
    GaInAs/InP PIN photodiodes with low dark currents and capacitances have been successfully fabricated from material grown by atmospheric-pressure MOVPE. Both Zn-diffused and grown-in p+-n homojunction material have provided yields of over 70% for devices with leakage currents less than 20 nA. This growth technique, therefore, looks particularly appropriate for a reproducible, high-yield and inexpensive method of photodetector production.
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High-power superluminescent diode with reduced coherence length
  • Author(s): C.B. Morrison ; L.M. Zinkiewicz ; J. Niesen ; L. Figueroa
  • Source: Electronics Letters, Volume 21, Issue 19, p. 840 –841
  • DOI:  10.1049/el:19850592
  • Type: Article
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  • p. 840 –841 (2)
    In work with superluminescent diodes, a significant new device structure has been developed that produces a spectral bandwidth of 160 Å at a power of 10 mW CW at room temperature. This spectrum has a Fabry-Perot modulation depth of less than 25%. These results point to a coherence length of about 45 μm, making this light source very useful for fibre-optic gyroscope applications.
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Required grading length to eliminate the heterojunction spike in npn In0.52Al0.48As/In0.53Ga0.47As/InP bipolar transistors
Computer-aided design of dielectric resonator filters in waveguide sections below cutoff
  • Author(s): R. Vahldieck  and  W.J.R. Hoefer
  • Source: Electronics Letters, Volume 21, Issue 19, p. 843 –844
  • DOI:  10.1049/el:19850594
  • Type: Article
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  • p. 843 –844 (2)
    The letter describes the analysis and design of a class of dielectric resonator filters in waveguide sections below cutoff. In these filters evanescent-mode coupling between the resonators can be realised by either an air-filled waveguide section or a dielectric slab-loaded waveguide section. Metallising the dielectric slab on both sides reduces the length of the coupling section and improves the stopband attenuation significantly. Filter characteristics can be predicted very accurately using a mode-matching technique to calculate the S-matrix of the filter component. This method accounts for the effect of finite metallisation thickness and higher-order modes.
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Monolithic 2.1 Gbit/s decision circuit with a decision threshold ambiguity width of less than 10 mV
  • Author(s): M. Suzuki  and  K. Hagimoto
  • Source: Electronics Letters, Volume 21, Issue 19, p. 844 –846
  • DOI:  10.1049/el:19850595
  • Type: Article
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  • p. 844 –846 (3)
    An Si bipolar monolithic decision circuit for practical use is developed using an improved circuit technique and super self-aligned process technology with the reliable 1.25 μm rule. The circuit consists of a slice amplifier, a master-slave D flip-flop and an output buffer. This circuit is capable of operating up to 2.1 Gbit/s with a decision threshold ambiguity width of less than 10 mV. In addition, a clock phase margin of 250 degrees and power dissipation of 640 mW at VEE=−6 V can be achieved.
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Effective screen for fast aging InGaAsP BH lasers using electrical derivatives
  • Author(s): M.M. Choy  and  C.E. Barnes
  • Source: Electronics Letters, Volume 21, Issue 19, p. 846 –848
  • DOI:  10.1049/el:19850596
  • Type: Article
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  • p. 846 –848 (3)
    We report here the first use of electrical derivatives to predict threshold current degradation rates for InGaAsP, etched mesa BH lasers. Fast aging lasers are found to display a post-threshold IdV/dI temperature dependence which sets them apart from slow agers. This signature is explained in terms of a nonlinear current leakage path in the confinement layers. We propose the use of the IdV/dI temperature signature as a screen to eliminate fast aging lasers in high-reliability applications.
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Comment: Effect of magnetic field on n+nn+ GaAs ballistic diode
Reply: Effect of magnetic field on n+nn+ GaAs ballistic diode
Intrinsic lineshape and FM response of modulated semiconductor lasers
  • Author(s): E. Eichen ; P. Melman ; W.H. Nelson
  • Source: Electronics Letters, Volume 21, Issue 19, p. 849 –850
  • DOI:  10.1049/el:19850599
  • Type: Article
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  • p. 849 –850 (2)
    A new method for measuring the FM response and the intrinsic linewidth of modulated semiconductor lasers is reported. No additional stochastic line broadening has been observed for direct modulation of buried-heterostructure 1.3 μm lasers with modulation depths of less than 20%. Thus FSK systems employing heterodyne detection are expected not to exhibit any additional phase noise penalty due to direct current modulation.
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Limits to power transmission in optical fibres
Transmission loss behaviour of PCVD fibres in H2 atmosphere
Single-frequency operation of an optically pumped monolithic Nd:YAG laser at 1.3 μm
Gigahertz-band analogue switch using bipolar super self-aligned process technology
New test structure for VLSI self-test: the structured test register (STR)
Effect of photon lifetime on absorptive bistability in inhomogeneously pumped lasers
Origin of spurious modes in the analysis of optical fibre using the finite-element or finite-difference technique
Loss-limited transmission at 140 Mbit/s over 30 km of single-mode fibre using a 1.3 μm LED
Millimetre-wave microstrip subharmonically pumped mixer
Digital communication receiver with integrated MAP synchronisation and ML demodulation
Biconical taper coaxial optical fibre coupler
Circuit theoretic analysis of resonance transformers
  • Author(s): J.A. Heinen  and  R.J. Niederjohn
  • Source: Electronics Letters, Volume 21, Issue 19, p. 866 –867
  • DOI:  10.1049/el:19850611
  • Type: Article
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  • p. 866 –867 (2)
    ‘Resonance transformers’ are electrical networks that, in a limited sense, act as standard transformers, the limitation being that such operation takes place only at one frequency. General conditions are derived under which a given two-port network can act as a resonance transformer. Examples are included to demonstrate the results and to provide a comparison with previously published work.
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Demodulation of optical DPSK using in-phase and quadrature detection
Precise control of Reggia-Spencer phase shifter
Reduction of geometric taper losses in the PCVD process
Fabrication of antimony oxide-doped silica fibres by the VAD process
The need for an explicit model describing MOS transistors in moderate inversion
  • Author(s): M. Bagheri  and  C. Turchetti
  • Source: Electronics Letters, Volume 21, Issue 19, p. 873 –874
  • DOI:  10.1049/el:19850616
  • Type: Article
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  • p. 873 –874 (2)
    Explicit expressions are derived for the drift and diffusion components of the channel current as a function of position along the channel of a MOSFET. It is shown that in moderate inversion the assumption that the channel current is ‘mostly due to diffusion’ or ‘mostly due to drift’ can lead to not only quantitative but also qualitative errors, since drift and diffusion can dominate simultaneously, but at different parts of the channel.
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Rectangular ring and H-shaped microstrip antennas—alternatives to rectangular patch antenna
  • Author(s): V. Palanisamy  and  R. Garg
  • Source: Electronics Letters, Volume 21, Issue 19, p. 874 –876
  • DOI:  10.1049/el:19850617
  • Type: Article
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  • p. 874 –876 (3)
    H-shaped and rectangular ring microstrip antennas have been compared with the commonly used rectangular patch antenna. It has been found that the H-shaped patch antenna is smaller in size (about half), and is broadbeam but with narrow bandwidth. On the other hand, for larger bandwidth and/or narrow beamwidth applications a rectangular ring antenna is better than a rectangular patch antenna. Because of size reduction the H-shaped patch looks attractive for UHF applications.
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Incoherent FSK
  • Author(s): L.C. Walters
  • Source: Electronics Letters, Volume 21, Issue 19, page: 876 –876
  • DOI:  10.1049/el:19850618
  • Type: Article
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  • p. 876 (1)
    Binary incoherent FSK detection protocols can be extended to demand that the energy associated with one tone frequency shall exceed that corresponding to the other tone by a factor other than unity. The resultant error, nonerror and reject probabilities are calculated for the case of a Rayleigh-fading signal amplitude against constant-power Gaussian noise and extended to the case where the RMS noise amplitude is itself subject to Rayleigh fading.
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Improvement of side-mode suppression ratio of a single-mode SCC semiconductor laser
  • Author(s): Zhou Bingkun ; Wang Jianglin ; Zhang Hanyi
  • Source: Electronics Letters, Volume 21, Issue 19, p. 877 –878
  • DOI:  10.1049/el:19850619
  • Type: Article
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  • p. 877 –878 (2)
    A new way to improve the single-longitudinal-mode spectrum of short-coupled-cavity (SCC) semiconductor lasers is reported. It is found that an antireflective coating on the end facet of the laser diode in the SCC cavity is necessary for high-quality single-mode operation. Based on the theoretical analyses, a new type of miniature SCC laser has been constructed and demonstrated. Single-mode output with 35–40 dB side-mode suppression ratio has been obtained under CW and 150 MHz modulation conditions.
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Planar monolithic integration of a Schottky photodiode and a GaAs field-effect transistor for 0.8 μm-wavelength applications
  • Author(s): H. Verriele ; S. Maricot ; M. Constant ; J. Ramdani ; D. Decoster
  • Source: Electronics Letters, Volume 21, Issue 19, p. 878 –879
  • DOI:  10.1049/el:19850620
  • Type: Article
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  • p. 878 –879 (2)
    A planar monolithic integrated photoreceiver suitable for 0.8 μm-wavelength optical communication systems has been realised. It consists of a GaAs Schottky photodiode associated with a GaAs FET. Sensitivities, response times and noise properties of the integrated circuit have been measured and are explained, taking into account various effects such as doping level, thickness of the depletion region and capacitance of the diode.
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Novel method for instantaneous determination of frequency of transmitters over wide bandwidths
Experimental verification of a VMOS UHF power transistor model and design
Observation of negative differential resistance in CHIRP superlattices

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