A dispersion shifted optical fiber where a radius r.sub.0 of a first center segment is 0.5 m to 2.8 m, and a relative refractive index difference .sub.0 is 0.4% or more and 0.9% or less. A radius r.sub.1 of a first segment is 1.8 m or more and 4.5 m or less. A radius r.sub.2 of a second segment is 4.0 m or more and 8.0 m or less, and a relative refractive index difference .sub.2 is 0.00% or more and 0.07% or less. A radius r.sub.3 of a third segment is 4.5 m or more and 8.5 m or less, and a relative refractive index difference .sub.3 is 0.285% or more and 0.5% or less. A radius r.sub.4 of a fourth segment is 8.0 m or more and 16.0 m or less, and a relative refractive index difference .sub.4 is 0.005% or more and 0.04% or less.

Disclosed herein are optical waveguide fibers comprising: (I) a core comprising an outer radius r.sub.1, a maximum refractive index delta percent .sub.1max and core alpha, , of larger than 5; and (II) a cladding surrounding the core, the cladding comprising: (i) an inner cladding region having outer radius r.sub.2 and refractive index delta percent .sub.2, wherein .sub.1max>.sub.2; (ii) a trench region surrounding the inner cladding region, the trench region having an outer radius, r.sub.3 where r.sub.310 microns and refractive index delta percent .sub.3; and (iii) an outer cladding region having chlorine concentration of 1.2 wt. % surrounding the trench region and comprising refractive index delta percent .sub.4, wherein .sub.1max>.sub.4 and .sub.2>.sub.3, and .sub.4>.sub.3 and wherein the difference between .sub.4 and .sub.3 is 0.12 percent.

Disclosed herein are optical waveguide fibers comprising: (I) a core comprising an outer radius r.sub.1, a maximum refractive index delta percent .sub.1 max and core alpha, , of larger than 5; and (II) a cladding surrounding the core, the cladding comprising: (i) an inner cladding region having outer radius r.sub.2 and refractive index delta percent .sub.2, wherein .sub.1max>.sub.2; (ii) a trench region surrounding the inner cladding region, the trench region having an outer radius, r.sub.3 where r.sub.310 microns and refractive index delta percent .sub.3; and (iii) an outer cladding region having chlorine concentration of 1.2 wt. % surrounding the trench region and comprising refractive index delta percent .sub.t, wherein .sub.1max>.sub.4 and .sub.2>.sub.3, and .sub.4>.sub.3 and wherein the difference between .sub.4 and .sub.3 is 0.12 percent.

Disclosed herein are optical waveguide fibers comprising: (I) a core comprising an outer radius r.sub.1, a maximum refractive index delta percent .sub.1 max and core alpha, , of larger than 5; and (II) a cladding surrounding the core, the cladding comprising: (i) an inner cladding region having outer radius r.sub.2 and refractive index delta percent .sub.2, wherein .sub.1max>.sub.2; (ii) a trench region surrounding the inner cladding region, the trench region having an outer radius, r.sub.3 where r.sub.310 microns and refractive index delta percent .sub.3; and (iii) an outer cladding region having chlorine concentration of 1.2 wt. % surrounding the trench region and comprising refractive index delta percent .sub.4, wherein .sub.1max>.sub.4 and .sub.2>.sub.3, and .sub.4>.sub.3 and wherein the difference between .sub.4 and .sub.3 is 0.12 percent.

A rollable optical fiber ribbon utilizing low attenuation, bend insensitive fibers and cables incorporating such rollable ribbons are provided. The optical fibers are supported by a ribbon body, and the ribbon body is formed from a flexible material such that the optical fibers are reversibly movable from an unrolled position to a rolled position. The optical fibers have a large mode filed diameter, such as 9 microns at 1310 nm facilitating low attenuation splicing/connectorization. The optical fibers are also highly bend insensitive, such as having a macrobend loss of 0.5 dB/turn at 1550 nm for a mandrel diameter of 15 mm.

Multimode beam combiners include at least one gradient-step index optical fiber in which a refractive index difference at a core/cladding interface is selected to provide a numerical aperture so as to provide stable, uniform beam output. One or more such fibers is formed into a tapered bundle than can be shaped to provide a selected illuminated aperture. The fibers in the bundle can be separated by respective tapered claddings so as to be optically coupled or uncoupled. Illumination systems can include a plurality of such fibers coupled to a plurality of laser diodes or other light sources.