By Topic

# Electronics Letters

## Filter Results

Displaying Results 1 - 25 of 69
• ### Low threshold, large To injection laser emission from (InGa)As quantum dots

Publication Year: 1994, Page(s):1416 - 1417
Cited by:  Papers (93)  |  Patents (8)
| | PDF (172 KB)

Low threshold, large To injection laser emission via zero-dimensional states in (InGa)As quantum dots is demonstrated. The dots are formed due to a morphological transformation of a pseudomorphic In0.5Ga0.5As layer. Laser diodes are fabricated with a shallow mesa stripe geometry View full abstract»

• ### Noise properties of electrically gainswitched 1.5 μm DFB lasers after spectral filtering

Publication Year: 1994, Page(s):1418 - 1419
Cited by:  Papers (4)
| | PDF (168 KB)

The authors show that spectral filtering of short pulses from an electrically gain-switched 1.5 μm DFB laser produces a substantial increase (12 dB) in the noise of the pulse train due to a mode partition effect. The implication of these results is considered for the situation where an erbium doped fibre amplifier is used to amplify gain-switched pulses View full abstract»

• ### Relaxation oscillation suppression in tunable fibre lasers

Publication Year: 1994, Page(s):1419 - 1421
Cited by:  Papers (3)
| | PDF (244 KB)

The concept of relaxation oscillation damping of a tunable fibre laser with a nonlinear absorber is discussed. The principle of operation is illustrated through a numerical model with a nonlinear optical loop mirror as the damping element. Results with complete elimination of relaxation oscillations are presented View full abstract»

• ### Self-starting passively modelocked fibre laser exploiting polarisation evolution in MQW waveguide

Publication Year: 1994, Page(s):1421 - 1422
Cited by:  Papers (1)
| | PDF (152 KB)

The authors give experimental evidence for a new type of modelocking mechanism in Er-doped fibre lasers, based on polarisation evolution in an intracavity MQW waveguide. Experiments indicate that anisotropic properties of MQW waveguides can continuously start the modelocking process View full abstract»

• ### 1.7 Gbit/s transmission over 165 km of dispersion-shifted fibre using spectrum-sliced fibre amplifier light source

Publication Year: 1994, Page(s):1427 - 1428
Cited by:  Papers (5)  |  Patents (1)
| | PDF (184 KB)

The authors have demonstrated 1.7 Gbit/s transmission over 165 km of dispersion-shifted fibre using a spectrum-sliced fibre amplifier light source. To the authors' knowledge, this represents the largest bit-rate distance product (280 Gbit/s km) ever demonstrated using an incoherent light source. The dispersion penalty was very small (~0.3 dB) even at a wavelength 10 nm away from the dispersion-zer... View full abstract»

• ### Improving the recognition performance by using a parallel-branch subunit model based on misrecognised data

Publication Year: 1994, Page(s):1380 - 1382
| | PDF (248 KB)

An initialisation and training method using a parallel-branch subunit model is obtained which uses a continuous hidden Markov model for improved recognition performance. The model is obtained by adding a new subunit branch based on misrecognised data in the training data to the previous parallel branches for that subunit. This procedure is shown to be efficient and gives good word recognition perf... View full abstract»

• ### Simple technique for measuring cavity loss in semiconductor lasers

Publication Year: 1994, Page(s):1422 - 1424
Cited by:  Papers (5)  |  Patents (18)
| | PDF (248 KB)

A new technique for measuring the cavity loss of semiconductor lasers is introduced. The cavity loss is deduced from the Fabry-Perot oscillations in the spontaneous emission well below the bandgap of the active region. This approach, referred to as the below-bandgap technique, is simple, applicable to both Fabry-Perot and DFB lasers, and is capable of measuring cavity losses with few restrictions ... View full abstract»

• ### Distance limits of 10 to 20 Gbit/s FSK transmission on standard fibre

Publication Year: 1994, Page(s):1428 - 1430
Cited by:  Papers (2)
| | PDF (272 KB)

A simple analysis is performed on an FSK transmission system using a high FM efficiency, high bandwidth DFB laser as a simple DFB transmitter and an FM/AM converter as an optical signal processor. It shows that optimum optical processing pushes the transmission limits to 150 km at 10 Gbit/s and to 40 km at 20 Gbit/s View full abstract»

• ### Robust learning algorithm for blind separation of signals

Publication Year: 1994, Page(s):1386 - 1387
Cited by:  Papers (55)  |  Patents (4)
| | PDF (184 KB)

The authors present a novel, efficient, self-normalising, unsupervised adaptive learning algorithm for the on-line (real-time) separation of statistically independent unknown source signals from a linear mixture of them. In contrast to the known algorithms the new algorithm allows the separation (or extraction) of extremely badly scaled signals (i.e. some or even all of the source and/or sensor si... View full abstract»

• ### Integrated optics for optical head applications

Publication Year: 1994, Page(s):1403 - 1404
Cited by:  Patents (5)
| | PDF (172 KB)

A waveguide structure for use in optical head systems is presented. The fabricated structures are 10×2×2 mm3 and are <0.2 g in mass. The waveguides propagate data and feedback signals for tracking and focusing. The proper generation of these signals and their sensitivity to the accompanying imaging optics are demonstrated View full abstract»

• ### Coupling structure for superconducting disk filters

Publication Year: 1994, Page(s):1424 - 1425
Cited by:  Papers (4)  |  Patents (5)
| | PDF (192 KB)

A new coupling structure for superconducting disk-filters that features a feeder extending into the neighbouring disk resonator is proposed. Simulation and experimental results demonstrate that the coupling structure reduces ripple in end-coupled disk filters View full abstract»

• ### Millimetre-wave signal generation using pulsed semiconductor lasers

Publication Year: 1994, Page(s):1430 - 1431
Cited by:  Papers (22)  |  Patents (5)
| | PDF (184 KB)

A novel technique for millimetre-wave signal generation using a pulsed semiconductor laser is proposed and demonstrated. Optical filtering is used to select only two modes and suppress all other modes in the optical spectrum of the laser. The two selected modes beat together in a photodiode to generate a millimetre-wave signal with 100% modulation depth View full abstract»

• ### Solving recurrence relations involving floor and ceiling functions

Publication Year: 1994, Page(s):1391 - 1393
| | PDF (196 KB)

A rounding lemma is presented which has applications in the field of discrete mathematics. The lemma can be used to simplify complex terms and analyse certain recurrence relations View full abstract»

• ### 0.85 μm bottom-emitting vertical-cavity surface-emitting laser diode arrays grown on AlGaAs substrates

Publication Year: 1994, Page(s):1406 - 1407
Cited by:  Papers (2)  |  Patents (5)
| | PDF (196 KB)

The first 0.85 μm 8×8 bottom-emitting vertical-cavity surface emitting laser diodes (VCSELs) have been grown on AlGaAs substrates. Their characteristics are the same as those of VCSELs grown on GaAs substrate. The authors have also fabricated 8×8 independently addressable VCSEL arrays which exhibited good lasing characteristics and uniform threshold current density View full abstract»

• ### Class of algebraically constructed permutations for use in pseudorandom interleavers

Publication Year: 1994, Page(s):1378 - 1379
Cited by:  Papers (4)  |  Patents (27)
| | PDF (156 KB)

The author shows that Lempel-Costas (LC) arrays when treated as permutations possess ideal properties for use in pseudorandom interleavers. The basic theory of interleavers is reviewed and the necessary conditions imposed on permutations for successful operation of pseudorandom interleavers are given. Proof that LC arrays satisfy the conditions, and a comparison with randomly constructed permutati... View full abstract»

• ### Cascading nonlinearities in KTP waveguides at communications wavelengths

Publication Year: 1994, Page(s):1400 - 1401
Cited by:  Papers (1)
| | PDF (184 KB)

Self-phase modulation due to the cascading of second-order nonlinearities is reported in segmented KTP channel waveguides in the communications band at 1587 nm. Peak nonlinear phase shifts are ~π/2 View full abstract»

• ### Kink-like effect in long n-channel twin-gate fully-depleted SOI MOSFETs

Publication Year: 1994, Page(s):1456 - 1458
Cited by:  Patents (2)
| | PDF (232 KB)

Twin-gate structures consisting of the series combination of two short-channel SOI MOSFETs of different lengths with a common gate have previously demonstrated kink-free and very flat output characteristics. The authors observe and explain that when using long-channel fully-depleted twin-gates a kink-like effect reappears and seriously damages the output conductance View full abstract»

• ### Circularly polarised dielectric resonator antenna

Publication Year: 1994, Page(s):1361 - 1362
Cited by:  Papers (32)  |  Patents (9)
| | PDF (180 KB)

A circularly polarised dielectric resonator antenna is reported. The circular polarisation is obtained by exciting the two orthogonal HE 11δ modes of a cylindrical ring dielectric resonator in phase-quadrature. Measured results show that the antenna has an axial ratio of less than 3 dB over a beam width of 100° with a minimum value of ~0.5 dB in this range View full abstract»

• ### Offset-fed microstrip reflectarray antenna

Publication Year: 1994, Page(s):1363 - 1365
Cited by:  Papers (9)
| | PDF (232 KB)

A microstrip reflectarray fed with a feed horn offset at a given angle is demonstrated for the first time. The phase considerations for an offset feed horn are applied to a 12 element array of rectangular microstrip patch antennas, operating in X-band, allowing accurate predictions of the redirected radiation based on the offset angle of the feed horn View full abstract»

• ### Multichannel FM-TV transmission using an engineered 1.3 μm praseodymium-doped fluoride fibre amplifier

Publication Year: 1994, Page(s):1431 - 1432
Cited by:  Papers (4)
| | PDF (184 KB)

The authors report the first use of a praseodymium-doped fluoride fibre amplifier (PDFFA) in a 24 TV channel FM-SCM transmission experiment. Twenty-four analogue FM-SCM-TV channels were amplified by a PDFFA without any observable degradation in picture quality. By using a single PDFFA as a post-amplifier, transmission over 104 km of standard' 1.3 μm optimised fibre was demonstrated with a tota... View full abstract»

• ### High power, high gain optical fibre amplifier for multiwavelength transmission systems

Publication Year: 1994, Page(s):1411 - 1413
Cited by:  Papers (7)  |  Patents (7)
| | PDF (256 KB)

A new type of optical fibre amplifier, a hybrid amplifier', especially developed for multiwavelength long distance transmission systems in the 1.55 μm window is presented. A 38 dB small signal gain, an +18 dBm saturation output power, a very flat gain spectrum and a very big signal-to-noise-ratio are obtained View full abstract»

• ### New phasing scheme of N-multiple carriers for reducing peak-to-average power ratio

Publication Year: 1994, Page(s):1382 - 1383
Cited by:  Papers (17)  |  Patents (12)
| | PDF (144 KB)

The authors propose a new phasing scheme to reduce the peak-to-average power ratio (PAPR) for N-multiple carriers. Numerical results indicate that the proposed scheme yields a PAPR within 3.01 dB for up to 300 carriers and that the PAPR approaches 2.65 dB as the carrier number increases. Experiments using CW and DSB-AM signals confirm the validity of the proposed scheme View full abstract»

• ### Results of 11.6 GHz radiometric experiment in Nigeria: second year

Publication Year: 1994, Page(s):1452 - 1453
Cited by:  Papers (1)
| | PDF (176 KB)

Three experiments were set up within a joint African radiometric propagation measurement program to provide data at frequencies above 10 GHz for predictive modelling. The authors report the results of the second year of measurements in Ile-Ife, Nigeria. Compared with ITU-R (formerly CCIR) predictions, the rain measurements agree fairly well but the path attenuation results differ significantly View full abstract»

• ### 1.55 μm fluoride-based EDFA with gain-flatness control for multiwavelength applications

Publication Year: 1994, Page(s):1407 - 1409
Cited by:  Papers (8)  |  Patents (13)
| | PDF (284 KB)

A new technique for flat gain control over a large range of input power with 1.55 μm fluoride-based erbium-doped fibre amplifiers is reported. It relies on the monitoring of backward-propagating amplified spontaneous emission. This technique is promising for future multiwavelength systems, where signal power or channel number variations may occur View full abstract»

• ### Efficient technique for computing the RCS of curved surfaces at low grazing angles

Publication Year: 1994, Page(s):1447 - 1449
Cited by:  Papers (1)
| | PDF (232 KB)

The authors present a fast and efficient alternative technique for evaluating the PO integral at aspects where no stationary phase points exist, yielding a nonzero field for scattering at low grazing angles to a curved surface 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