Open AccessOrbital angular momentum generation in a dual-ring fiber based on the phase-shifted coupling mechanism and the interference of supermodes
Author(s) -
Wei Huang,
Yujie Xiong,
Haibo Qin,
Yange Liu,
Binbin Song,
Shengyong Chen
Publication year - 2020
Publication title -
optics express
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.394
H-Index - 271
ISSN - 1094-4087
DOI - 10.1364/oe.391372
Subject(s) - superposition principle , optics , coupling (piping) , physics , angular momentum , fiber , interference (communication) , phase (matter) , resonance (particle physics) , optical fiber , wavelength , single mode optical fiber , ring (chemistry) , topology (electrical circuits) , materials science , atomic physics , telecommunications , quantum mechanics , computer science , chemistry , mathematics , channel (broadcasting) , metallurgy , composite material , organic chemistry , combinatorics
Based on the phased-shifted interference between supermodes, a novel method that can directly convert LP 01 mode to orbital angular momentum (OAM) mode in a dual-ring microstructure optical fiber is proposed. In this fiber, the resonance between even and odd HE 11 modes in inner ring and higher order mode in outer ring will form two pairs of supermodes, and the intensities and phases of the complete superposition mode fields for the involved supermodes created by the resonance at different wavelengths and propagating lengths are investigated and exhibited in this paper. We demonstrate that OAM mode can be generated from π/2-phase-shifted linear combinations of supermodes, and the phase difference of the even and odd higher order eigenmodes can accumulate to π/2 during the coupling process, which is defined as "phase-shifted" conversion. We build a complete theoretical model and systematically analyze the phase-shifted coupling mechanism, and the design principle and optimization method of this fiber are also illustrated in detail. The proposed microstructure fiber is compact, and the OAM mode conversion method is simple and flexible, which could provide a new approach to generate OAM states.