Step-index profile

About: Step-index profile is a research topic. Over the lifetime, 3104 publications have been published within this topic receiving 53199 citations.

Anti-iridescent coatings with gradient refractive index

Abstract: A substantially transparent glazing article has an optically functional coating on a transparent substrate. The coating has an optically functional topcoat layer and an anti-iridescence layer between the topcoat and the substrate. The refractive index anti-iridescence layer is (i) higher than the refractive index of the substrate in a first high refractive index zone directly on the substrate surface, (ii) lower than that of the first high refractive index zone in a low refractive index zone directly on the first high refractive index zone, and (iii) higher than that of the low refractive index zone in a second high refractive index zone directly on the low refractive index zone. The refractive index of the anti-iridescence layer varies in at least one of the zones substantially continuously with distance from the substrate surface. Contiguous zones may together form a single gradient index zone. The anti-iridescence layer is less thick than the optically functional layer and substantially reduces or eliminates iridescence without significantly impairing the optical functionality of the top coat layer.

Application of Fresnel diffraction to nondestructive measurement of the refractive index of optical fibers

Abstract: A nondestructive technique, based on Fresnel diffraction from phase objects, is proposed for specifying the refractive indices of optical fibers without requiring index matching liquid The method involves measurement of normalized intensity distribution on the Fresnel diffraction pattern of a monochromatic plane wave diffracted from a fiber, and evaluation of the fiber core refractive index from the intensity distribution by the least-square method It is also shown that for the case of an unknown fiber core radius, by fitting a suitable theoretical intensity distribution on the corresponding experimental intensity distribution, the core radius and refractive index can be obtained with reasonable accuracy Simulation and experimental studies show that the technique is reliable and quite sensitive to refractive index change

Sensitivity of slanted fibre Bragg gratings to external refractive index higher than that of silica

Abstract: The influence of external refractive index higher than that of silica on the transmission spectra properties of slanted fibre Bragg gratings is investigated. An analytical method is presented for their potential use as refractometers for refractive index ranges beyond 1.45.

Profile dispersion in multimode fibres: measurement and analysis

Abstract: An electronically scanned interference microscope has been used to measure the refractive-index profile and its dispersion in optical fibres From these measurements, we find that the power-law profile that best equalises modal delays in GeO2-S1O2 fibres should have an exponent that varies between 19 and 25 in the wavelength range from 05 to 11 µm and is close to 2 at 09 µm