Equalizing modal delay of high order modes in bend insensitive multimode fiber

Abstract

Described are multimode optical fibers in which the differential in the mode delay for higher order modes is reduced for bending insensitive MMF. The result is preservation of low differential mode delay and high bandwidth while low bend loss is achieved. The designs are based on choosing a combination of a core profile and a cladding structure with a negative trench positioned at a radius related to the core profile. A feature of the preferred embodiments is a core with a hybrid refractive index profile. The hybrid refractive index profile is essentially a combination of a standard alpha profile and a step profile at the outer edge of the alpha profile.