Design of few-mode optical fibers with air-hole structure for MIMO-less data transmission

Abstract

Rapidly space-division multiplexing (SDM) techniques have drawn attention because the traditional available physical dimensions to orthogonally multiplex data have been almost exhausted. Few-mode fiber becomes a viable option to realize a high-density SDM system. Thus, we propose an air-hole assisted elliptical ring fiber. Four air-holes are introduced surrounding the elliptical ring fiber, and one air-hole is in the core, which can prevent higher-order modes to be cutoff and improve the degeneracy between modes to achieve multiple-input multiple-output-free data transmission. This fiber can support 14 modes in a wide wavelength range from 1.52 to 1.58 μm (h = 5.0 μm, dx = 0.3 μm, and dy = 1.1 μm), and the effective index difference of its adjacent modes is larger than 1.25 × 10 − 4. The fiber we designed would be a strong candidate for SDM to improve optical transmission capacity.