# Electronics Letters

## Filter Results

Displaying Results 1 - 25 of 38
• ### Crosstalk characteristics of lens-like Ti-LiNbO3 intersecting channel waveguides

Publication Year: 1983, Page(s):805 - 806
Cited by:  Papers (3)
| | PDF (286 KB)

Crosstalk characteristics of intersecting channel waveguides are presented. Full diffusion times of various Ti film thicknesses are measured first. The concentration distributions in Ti-LiNbO3 crosschannel waveguides are then calculated and compared with the measured distribution. The lens-like medium is the crossover region of crosstalk between Â¿n and 2Â¿n crosschannel waveguide. View full abstract»

• ### Accurate analysis of the abrupt discontinuity in a dielectric waveguide

Publication Year: 1983, Page(s):806 - 808
Cited by:  Papers (3)
| | PDF (549 KB)

An accurate analysis of the step discontinuity in a dielectric waveguide is presented. The analysis incorporates the iterative procedure into Lewin's approximate analysis of the laser emission extending Hockam's idea. The numerical solution of the problem converges very fast. View full abstract»

• ### Wideband frequency-shift keying with a spectrally bistable cleaved-coupled-cavity semiconductor laser

Publication Year: 1983, Page(s):808 - 809
| | PDF (419 KB)

By operating a cleaved-coupled-cavity (C3) laser in a spectrally bistable regime with large hysteresis we demonstrate a new kind of high-speed FSK transmitter. This scheme can tolerate large fluctuations in modulation signal amplitude and show a detection limited switching time of 1 ns, indicating the possibility of high-speed high-reliability FSK systems. View full abstract»

• ### Broadband microstrip directional coupler

Publication Year: 1983, Page(s):809 - 810
| | PDF (374 KB)

A nonuniform microstrip directional coupler with sinusoidally modulated coupling function is presented. The ripple and the amplitude response are controlled by the index of modulation m and the periodicity P of the function. For demonstration, a 20 dB Â± 6% coupler is constructed on two different substrates and the experiment shows much flatter coupling response than the uniform or exponential lin... View full abstract»

• ### Noise-cancelling switched-capacitor (SC) filtering technique

Publication Year: 1983, Page(s):810 - 811
Cited by:  Papers (16)
| | PDF (281 KB)

A method of reducing the 1/f noise in SC filters is shown using an initialising technique. This technique also removes the input offset of the operational amplifier, and thus gives an offset-free SC building block. Experimental results for a first-order lowpass filter illustrating the above are presented. View full abstract»

• ### Measurement of spectra of and correlation between FM and AM noises in GaAlAs lasers

Publication Year: 1983, Page(s):812 - 813
Cited by:  Papers (11)
| | PDF (283 KB)

The FM- and AM-noise spectra of a CSP-type GaAlAs laser, and the correlation between FM and AM noises, were measured in the frequency range below 100 kHz with the bias current as a parameter. The measured spectra consist of power-independent 1/f noise and power-dependent white-noise components. A strong correlation is observed between the FM and AM noises when the output power is small. This fact ... View full abstract»

• ### Noise and responsivity of commercial p+n Ge avalanche photodiodes

Publication Year: 1983, Page(s):813 - 815
Cited by:  Papers (1)
| | PDF (389 KB)

Commercial p+n Ge APD samples from two manufacturers are shown to have comparable noise and responsivity, characterised by a quantum efficiency at 1.3 Â¿m wavelength of 0.7Â¿0.75, and a bulk leakage current density at 20 C of 2Â¿3Ã10Â¿4 A cmÂ¿2 before avalanche multiplication. Surface uniformity of avalanche gain is much better than on earlier n+p devices of the same diameter (100 Â¿m). View full abstract»

• ### Low-cost integrated RF six-port

Publication Year: 1983, Page(s):815 - 816
Cited by:  Papers (2)
| | PDF (283 KB)

An automated low-cost microstrip six-port measurement system is described which has broadband capability and high measurement sensitivity. The whole design is incorporated onto a single microstrip circuit assembly. View full abstract»

• ### Acousto-optic frequency shifter for single-mode fibres

Publication Year: 1983, Page(s):816 - 818
Cited by:  Papers (11)
| | PDF (663 KB)

A fibre-optic frequency shifter has been constructed using a birefringent single-mode fibre positioned asymmetrically within two acoustic resonators driven 90Â° out of phase. The incident wave in one polarisation state is coupled to a frequency-shifted wave in the orthogonal state. Sideband suppression of better than 20 dB is achieved. View full abstract»

• ### High-performance avalanche photodiode with separate absorption gradingÂ¿ and multiplication regions

Publication Year: 1983, Page(s):818 - 820
Cited by:  Papers (61)
| | PDF (592 KB)

High-speed operation of avalanche photodiodes with separated absorption and multiplication regions has been achieved by incorporating an intermediate bandgap InGaAsP gradingÂ¿ layer between the InP multiplication layer and the InGaAs absorption layer. These APDs also exhibit low dark currents, high quantum efficiencies and good avalanche gains. Sensitivity measurements have been made at 1.3 Â¿m a... View full abstract»

• ### Evanescent amplification in a single-mode optical fibre

Publication Year: 1983, Page(s):820 - 822
Cited by:  Papers (5)
| | PDF (496 KB)

By replacing a portion of the cladding of a single-mode fibre with a laser dye, amplification can be achieved by means of an evanescent field interaction. External gains as high as 22 dB have been measured by guiding both a pulsed pump and CW signal within the single-mode fibre. View full abstract»

• ### New negative-resistance device by a chirp superlattice

Publication Year: 1983, Page(s):822 - 823
| | PDF (292 KB)

A new type of supperlattice named CHIRP (coherent heterointerfaces for reflection and penetration) superlattice, in which the periodicity is gradually changed, is proposed. The electron transmissivity through the superlattice is modulated by the applied electric field. A possible application to a negative-resistance device is discussed. View full abstract»

• ### Surface-acoustic-wave bandpass filters on ZnO/Pyrex substrate with zero temperature coefficient

Publication Year: 1983, Page(s):823 - 824
| | PDF (290 KB)

Thick layers of ZnO (5Â¿10 Â¿m) deposited on Pyrex glass have been investigated in order to realise low-cost and temperature-stable surface-acoustic-wave bandpass filters. We describe the sputtering method used to grow the ZnO layer and we give the measured results of the acoustical and thermal properties for different film thicknesses. A high coupling coefficient (10%) and very good temperature s... View full abstract»

• ### Polarisation-preserving coupler with self aligning birefringent fibres

Publication Year: 1983, Page(s):825 - 826
Cited by:  Papers (8)
| | PDF (389 KB)

Polarisation-preserving directional couplers have been fabricated with birefringent fibres that self align their axes within the coupling region. The polarisation characteristics have been measured with the reliable spectral-averaging technique, and broadband extinction ratios of Â¿20 dB have been achieved, on average, in all ports. View full abstract»

• ### Optical properties for an antireflection-coated LD optical switch

Publication Year: 1983, Page(s):826 - 828
Cited by:  Papers (2)
| | PDF (469 KB)

Measured optical properties for an antireflection-coated laser-diode optical switch are described. With antireflection coatings, output level stability for injection current and temperature are much improved. The input and output signal spectra are the same. View full abstract»

• ### Normalisation of Fourier descriptors of planar shapes

Publication Year: 1983, Page(s):828 - 830
| | PDF (410 KB)

Fourier descriptors (FDs) are one of the efficient tools for discrimination of planar shapes. The problem of achieving a unique normalisation of the given set of FDs has not been solved satisfactorily. An improved method for normalisation which has applicability over a wider range of shapes is suggested in the letter. A sufficient condition for the axial symmetry of a contour is also given. View full abstract»

• ### Â¿-ray irradiation effect on transmission loss for ZrF4-based optical fibres

Publication Year: 1983, Page(s):830 - 831
| | PDF (302 KB)

The Â¿-ray irradiation effect on the transmission loss of ZrF4-BAF2-GdF3-AlF3 and ZrF4-BaF2-GdF3-AlF3-PbF2 optical fibres is investigated. Absorption bands are induced in the ultraviolet to near infrared region, and their tails increase the transmission losses in the mid-infrared region. Induced transmission losses for a dose of 106 R are 1000Â¿2300 dB/km in the 2Â¿4 Â¿m band. These values are com... View full abstract»

• ### Analytical expressions of 2-D complex cepstrum

Publication Year: 1983, Page(s):831 - 832
Cited by:  Papers (1)
| | PDF (281 KB)

An analytical expression for complex cepstrum of a 2-dimensional second-order (finite) real discrete signal is derived for minimum phase condition in terms of multinomial coefficients and signal values. The theoretical cepstral expression obtained agrees favourably with the actually computed cepsta using a reasonably large size DFT to minimise any effects of aliasing. A few important properties of... View full abstract»

• ### Determination of admittance of coaxial-line/rectangular waveguide junction

Publication Year: 1983, Page(s):832 - 834
| | PDF (344 KB)

An analytical approximate method to determine the admittance of a coaxial-rectangular waveguide junction is presented. The accuracy of the method is verified experimentally. View full abstract»

• ### Approximate expression for the resonant frequency of a rectangular patch antenna

Publication Year: 1983, Page(s):834 - 835
Cited by:  Papers (9)
| | PDF (250 KB)

An approximate expression is derived for the resonant frequency of a rectangular patch antenna. It shows explicitly the dependence of the resonant frequency on the characteristic parameters of the antenna. Accuracy of the expression is established by comparing the theoretical results with available measured results. View full abstract»

• ### Sensitivity behaviour of several two op-amp inverting and non-inverting integrators

Publication Year: 1983, Page(s):835 - 836
Cited by:  Papers (5)
| | PDF (245 KB)

Several integrators which are claimed to be useful for high-frequency filter design are compared. The basis of comparison is the sensitivity of the integrator magnitude and phase with respect to the time constants of the operational amplifiers. View full abstract»

• ### Chirped picosecond injection laser pulse transmission in single-mode fibres in the minimum chromatic dispersion region

Publication Year: 1983, Page(s):837 - 838
Cited by:  Papers (2)
| | PDF (335 KB)

We report the propagation of chirped picosecond InGaAsP injection laser pulses in single-mode fibres in the minimum chromatic dispersion wavelength region. The observed initial compression and subsequent broadening are in good agreement with theory and illustrate the implications of chirped pulse transmission for high-bandwidth communication in the 1.2Â¿1.6 Â¿m wavelength region. View full abstract»

• ### Analysis of the element pattern shape for circular arrays

Publication Year: 1983, Page(s):838 - 840
Cited by:  Papers (2)
| | PDF (422 KB)

Recent theoretical and experimental investigations have established the phase-mode technique for directional pattern synthesis in circular arrays of nonisotropic sources. For non-isotropic sources the possibility of phase-mode stability has emerged, indicating wideband directional patterns. In the letter a further examination analysing the shape of the element pattern for phase-mode stability is p... View full abstract»

• ### High-power single-longitudinal-mode operation of 1.3 Â¿m DFB-DC-PBH LD

Publication Year: 1983, Page(s):840 - 841
Cited by:  Papers (12)
| | PDF (292 KB)

CW light output power as high as 38 mW at room temperature and with a CW operable temperature as high as 80Â°C, both under single-longitudinal-mode operation, has been achieved for the first time in newly developed 1.3 Â¿m distributed-feedback (DFB) laser diodes with a double-channel planar buried heterostructure (DC-PBH). View full abstract»

• ### Stress and temperature effects on optical loss increase for phosphor-doped silica fibre in the long wavelength region

Publication Year: 1983, Page(s):842 - 843
Cited by:  Papers (1)
| | PDF (292 KB)

Irreversible loss increase in the long-wavelength region is first observed for phosphor-doped silica fibres with silicone resin layer by applying the stress at high temperature. The loss increment becomes larger for longer wavelengths. Experimental results show that the loss increase is strongly dependent on stress and temperature. View full abstract»

## Aims & Scope

Electronics Letters is internationally renowned for its rapid communication of new developments and emerging topics across the broad and interdisciplinary field of modern electronics and electrical engineering.

Full Aims & Scope

## Meet Our Editors

Editors-in-Chief

Professor Chris Toumazou
Director of the Biomedical Institute
Imperial College, London, UK

Professor Ian White