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.

Apparatus and method for a waveguide with an index profile manifesting a central dip for better energy extraction

Abstract: A method and apparatus is described that use an index-of-refraction profile having a significant central dip in refractive index (or another tailored index profile) within the core of a gain fiber or a gain waveguide on a substrate. The benefits of this central dip (more power with a given mode structure) are apparent when an input beam is akin to that of a Gaussian mode. In some embodiments, the invention provides a fiber or a substrate waveguide having an index profile with a central dip, but wherein the device has no doping. Some embodiments use a central dip surrounded by a higher-index ring in the index of refraction of the core of the fiber, while other embodiments use a trench between an intermediate-index central core portion and the ring, or use a plurality of rings and/or trenches. Some embodiments use an absorber in at least one core ring.

Design Optimization of Trench Index Profile for the same dispersion characteristics with SMF

Abstract: An optimized design on a trench index profile for bend-insensitive SMF is presented. The same dispersion characteristic with standard SMF with ultra low bending loss has been realized by optimization of trench index profile.

Fiber optic connector with double-clad stub fiber

Abstract: A fiber optic connector having a double-clad specialty optical stub fiber with a deep index core-to-inner-cladding profile and a raised index outer-cladding profile. The double-clad optical stub fiber abuts against a single-clad field optical fiber of the single-mode type to form an interface across which the primary mode traverses without significantly interfering with higher-order modes. The ratio of the radius of the inner cladding to the radius of the core of the stub fiber is less than 6.5:1. The index profile of the refractive index of the inner cladding is deep relative to the refractive index of the core to confine the primary mode within the core. The raised refractive index of the outer-cladding pulls the higher-order modes deeper into that region, reducing interference with the primary mode. The respective core diameters of the field and stub fibers are matched to avoid mode-field diameter mismatch.

Refractive index profile of fused-tapered fiber couplers.

Abstract: We investigate the refractive index profile evolution during the tapering of fused couplers. We assume the refractive index to be a linear function of the dopant concentration. The evolution of the refractive index profile is obtained by solving the diffusion-convection equation. The couplers are cleaved at different positions along the coupler axis, and the real refractive index profiles, measured using Refracted-Near-Field technique, are compared with the numerical solutions.

Disperson-shifted optical fiber employing dual shape core profile

Abstract: A dispersion-shifted optical fiber is obtained that has a refractive index distribution shape comprising a center core portion of high refractive index, a step core portion of lower refractive index than the center core portion, provided about the outer circumference thereof, and clad of lower refractive index than the step core portion, provided about the outer circumference of the step core, in which, by suitably setting structural parameters, both Aeff expansion and dispersion slope reduction are satisfactorily effected, simultaneously, under conditions that the optical fiber is substantially single-mode, and bending loss is held down to 100 dB/m or lower.