Efficient photodiode-waveguide coupling for hybrid integrated optical circuits

A GalnAsP edge-detecting photodiode was coupled with an SiO2-TiO2 single-mode waveguide in a simple hybrid integration scheme. The newly developed edge-detecting photodiode with a window region was used to improve photodiode durability.     

Estimation of multipath channel response in frequency selectivechannels

A novel discrete-time method is proposed for estimating the impulse response of a frequency-selective digitally modulated communication channel. The received signal is first demodulated and sampled and then the fourth-order cumulants of the resulting discrete-time sequence are estimated. The method estimates the channel impulse response from the complex cepstrum of the aforementioned fourth-order cumulants (i.e. tricepstrum). The method depends only on the second- and fourth-order statistics of the transmitted sequence and is capable of reconstructing nonminimum-phase impulse responses. Monte Carlo simulation results demonstrate the effectiveness of the method, its low sensitivity to observation noise, and its improved performance in terms of probability of error or the reconstructed transmitted sequence     

Interfacial stress singularities in a bimaterial wedge

In this paper methods of computing stress singularity factors for strain-hardening materials are reviewed. The methods are applied to calculation of these factors for a bimaterial wedge comprising two power-law hardening materials of arbitrary external and internal angles.     

Structure and processes of formation of oxide electrocatalysts

Translated from Khimicheskoe i Neftyanoe Mashinostroenie, No. 10, pp. 27–29, October, 1991.     

Automated design system for an axial fan

Translated from Khimicheskoe i Neftyanoe Mashinostroenie, No. 3, pp. 8–9, March, 1992.     

Composition validation and subjectivity in GenVoca generators

GenVoca generators synthesize software systems by composing components from reuse libraries. GenVoca components are designed to export and import standardized interfaces, and thus be plug-compatible, interchangeable, and interoperable with other components. We examine two different but important issues in software system synthesis. First, not all syntactically correct compositions of components are semantically correct. We present simple, efficient, and domain-independent algorithms for validating compositions of GenVoca components. Second, components that export and import immutable interfaces are too restrictive for software system synthesis. We show that the interfaces and bodies of GenVoca components are subjective, i.e., they mutate and enlarge upon instantiation. This mutability enables software systems with customized interfaces to be composed from components with “standardized” interfaces     

Is layering, harmful? [remote procedure call]

Remote procedure call (RPC) mechanisms over the US Department of Defense transmission control protocol. (TCP) can produce behavior analogous to the silly window syndrome because of a mismatched interface between the socket and the TCP modules. The detection and diagnosis of the problem are addressed. Some pointers to a design approach that could avoid the problems of mismatched communication layers are provided     

0.27-dB/km attenuation achieved by MSP preform process [opticalfibers]

Mechanically shaped preforms (MSP) have been demonstrated to combine economic non-CVD (chemical vapor deposition) processing and low loss, with a published value of 0.63 dB/km and a size of 30 fkm/preform. Improved processing is proposed which results in a minimum loss of 0.27 dB/km at 1550 nm. Preforms capable of yielding 150 fkm have been produced. Reboiling during preform stretching and fiber pulling is identified as the last remaining problem of the process     

The performance of depressed-cladding single-mode fibers withdifferent b/a ratios

Depressed-cladding single-mode fibers with a first cladding-to-core ratio (b/a) ranging from seven to one and relative refractive-index differences of the core from 0.25 to 0.35% and of the cladding from 0 to -0.2% are investigated experimentally with respect to the LP₁₁ mode cutoff properties, the mode-field diameter, the dispersion, and the bending attenuation. Numerical calculations based on actual profile parameters of the bend loss and the mode-field diameter agree well with experiment. It is demonstrated that low attenuation and bend losses independent of b/a can be obtained if the cutoff wavelength is kept constant by adjusting the core radius, the core index or the index of the first cladding