Core (optical fiber)

About: Core (optical fiber) is a research topic. Over the lifetime, 42714 publications have been published within this topic receiving 254753 citations.

Core Analysis By Low-field Nmr

Abstract: NMR core measurements have been made customarily in.high magnetic fields, emphasizing TI for pore-size evaluation or using chemical shift spectroscopy for quantitative differentiation of oil and water. However, new NMR logging tools use T2 measurements made at low field strengths and these measurements should be supported by core analysis. This paper illustrates that low field NMR T2 measurements made on water-saturated rock cores can be used to measure total porosity and extract T2-distributions. The T2-distributions are shown to be closely related to pore size distributions. Our experiments demonstrate that low field measurements are quantitative, even for cases where high field measurements fail. T2-distributions from water-saturated plugs are used to estimate producible fluids for sandstones and carbonates and to estimate clay bound water and matrix permeability. Although chemical shift spectroscopy is not feasible at low fields, a method is demonstrated on native state diatomites that permits the measurement of oil, water and gas saturation. In the case presented, it is also possible to determine the oil viscosity, in situ.

Optical and dielectric properties of partially resonant composites

Abstract: We analyze the two-dimensional potential around a coated cylinder placed in a nonuniform field. In two special cases the system behaves as if the core of the cylinder were enlarged and the shell absent. These are when the shell dielectric constant is the negative of either the core dielectric constant or the matrix dielectric constant. When the shell dielectric constant has a small imaginary part, the field can exhibit large fluctuations which remain localized near the surface of the coated cylinder.

Use of highly elliptical core fibers for two-mode fiber devices.

Abstract: The four complex, almost degenerate, second-order eigenmodes of a two-mode fiber having a circular core are reduced to two nondegenerate, linearly polarized second-order eigenmodes with stable-intensity lobe positions in a highly elliptical core fiber. Existing two-mode-fiber devices can be improved by this stabilization of the second-order modes. Practical sensors employing the two spatial modes as the two arms of an interferometer are described. The two arms of an interferometer of this type can have the same group delays, while the difference in phase delays is large.

Optical distribution system including light guide

Abstract: A flexible transmitting guide has a substantially transparent semi-solid core to which is shrink-fitted, or otherwise tightly clad, a transparent or translucent sleeve which is designed to laterally diffuse, disperse or refract a substantial component of light away from the core as it traverses the length of the guide. Thus, the clad core appears bright along its length and functions as a primary light source. In modifications of the device, the lateral dispersion of light passing along the core is enhanced by interposing cuts or discontinuities at intervals along its surface, or by providing a sleeve comprising an emulsion of light-reflecting particles. The light source may be adjacent to or separated from the core, and may comprise either a steady state, or pulsating source, ahead of which colored filters may be inserted, if desired. Numerous indoor and outdoor applications are contemplated for light guides in accordance with the present invention, including for signs, safety vests for traffic policemen, lighted canes for the disabled, lights for instrument panels, safety lights for vehicles and ships, and lights for interior and exterior decoration.