Broadband dispersion compensating ring-core fiber for orbital angular momentum modes

A well designed ring-core fiber can theoretically support numerous orbital angular momentum (OAM) modes with low crosstalk for space-division-multiplexing (SDM) data transmission, which is considered as a promising solution for overcoming the capacity crunch in optical communication network. However, the accumulated chromatic dispersion in OAM-fiber could limit the data speed and transmission distance of communication systems. A potential solution is to insert a dispersion compensation ring-core fiber with opposite-sign of dispersion in the transmission fiber along the fiber link. In this work, we propose a triple ring-core fiber with broadband negative dispersion. A highest negative dispersion of-24.47 ps/(nmmiddotkm) at 1550 nm and an average dispersion slope in the C band from-0.182 ps/(nm2middotkm) to 0.065 ps/(nm2middotkm) can be achieved to compensate multi-order dispersion. The effects of Ge-doping concentration fluctuation in the high-index ring core and fabrication errors on fiber geometric structures are also investigated. Furthermore, the effective mode area decreases as the widths of high-index rings increase due to the enhanced confinement ability. The designed triple ring-core fiber could offer potential for compensating OAM fiber links with positive dispersions.(c) 2022 Optica Publishing Group under the terms of the Optica Open Access Publishing Agreement

Automated summary

A well-designed ring-core fiber can support multiple OAM modes with low crosstalk. However, the accumulated chromatic dispersion in OAM fiber limits the data speed and transmission distance of communication systems. This study proposes a triple ring-core fiber with negative dispersion to compensate for multi-order dispersion.