Dispersion compensation for orbital angular momentum mode based on circular photonic crystal fiber. (6th August 2021)

• Record Type: Journal Article
• Authors: Liu, Exian; Yan, Bei; Xie, Jianlan; Peng, Yuchen; Gao, Feng; Liu, Jianjun
• Is Part Of: Journal of physics. Volume 54:Number 43(2021)
• Publication Date: 2021-08-06
• Subjects: photonic crystal fiber -- angular momentum mode -- dispersion compensation; Physics -- Periodicals; 530
• DOI: 10.1088/1361-6463/ac16fa
• Languages: English
• ISSNs: 0022-3727

Abstract

Abstract: In this work, a circular dual-core photonic crystal fiber is proposed for dispersion compensation for the controllable orbital angular momentum (OAM) mode by the inner-outer core mode coupling. This design can simultaneously realize a negative dispersion of up to −3039.45 ps nm −1 km −1 for OAM mode HE31 and a high effective index separation of 2.15 × 10 −3 within scalar linearly polarized (LP)21 mode group (HE31 and EH11 ) at 1.55 µ m, ensuring HE31 vortex mode robust propagation without channel crosstalk. Evolution of the combined effective index, OAM phase, and electric field is systemically verified functioning as wavelength during the inner-outer mode coupling. Structural parameter dependence of negative dispersion is demonstrated with respect to lattice constant, air hole size and air-filling fraction, remarkably suggesting that negative dispersion dip at phase-matching wavelength exhibits an enhanced blue shift with lattice constant of inner cladding increasing but a red shift with lattice constant of outer cladding. The feasibility of this design is demonstrated with an achievement of negative dispersion of −1773.21 ps nm −1 km −1 for EH11 mode at wavelength 1.55 µ m by tuning the structural parameter. This design is expected for fiber applications in OAM-based optical communication systems.