All-fiber mode converter based on long-period fiber gratings written in few-mode fiber

Yunhe Zhao; Yunqi Liu; Chenyi Zhang; Liang Zhang; Guangjun Zheng; Chengbo Mou; Jianxiang Wen; Tingyun Wang

doi:10.1364/OL.42.004708

All-fiber mode converter based on long-period fiber gratings written in few-mode fiber

Opt Lett. 2017 Nov 15;42(22):4708-4711. doi: 10.1364/OL.42.004708.

Authors

Yunhe Zhao, Yunqi Liu, Chenyi Zhang, Liang Zhang, Guangjun Zheng, Chengbo Mou, Jianxiang Wen, Tingyun Wang

PMID: 29140349
DOI: 10.1364/OL.42.004708

Abstract

We investigated an all-fiber mode converter based on long-period fiber gratings (LPFGs) written in the few-mode fiber. Mode conversion between the fundamental core mode and different higher-order core modes (LP₁₁, LP₂₁, and LP₀₂ modes) can be realized via a single LPFG with an efficiency of 99% at the resonance wavelength. Moreover, optimized mode conversion between the LP₀₁ and LP₂₁ modes can be realized by cascading two LPFGs with different grating pitches. The maximum conversion efficiency is estimated to be ∼99.5% at 1553 nm. The orbital angular momentum states with different topological charges (±1,±2) are demonstrated experimentally. The all-fiber LPFG mode converters could have promising applications in the mode-division multiplexing optical communications.