Design of solid-core Bragg few-mode fiber for short-reach MDM networks in [formula omitted] band

Abstract

We propose a solid-core Bragg few-mode fiber with alternating layers of high/low refractive indices. The refractive index of the low-index layer in the cladding is the same as that of the fiber core. The influences of filling ratio, periodic structure width and core size on neff, Δneff and Aeff are investigated. Bending loss of each guided mode and differential mode delay (DMD) between adjacent spatial modes are also studied at 1550 nm. With appropriate geometrical parameters, the minimum effective refractive index difference (minΔneff) between adjacent modes is 2×10−3 at 1550 nm. Wavelength-dependent performance is analyzed subsequently ranging from 1180 nm to 1630 nm. Numerical simulations indicate that such fiber could support 7 linearly polarized (LP) modes and have good bending insensibility performance. These results illustrate that the proposed fiber could be a promising candidate for mode division multiplexing to enhance optical transmission capacity.