Negative curvature fiber for suppressing high-order radial OAM modes transmission

• Published in: Results in physics Vol. 52; p. 106910
• Main Authors: Zhu, Zhenghan, Yan, Dexian, Li, Xiangjun, Zhang, Le, Li, Jining
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 01.09.2023; Elsevier
• Subjects: Higher-order radial mode; Modal map; OAM; Terahertz; OAM; Higher-order radial mode; Terahertz; Modal map
• ISSN: 2211-3797; 2211-3797
• DOI: 10.1016/j.rinp.2023.106910

•The designed fiber can support OAM modes transmission over a relatively wide range of 2.0–3.0 THz.•The cut-off condition of each vector mode has been obtained, and the excitation of second-order radial modes is avoided by mathematical analysis.•A design guide is proposed to provide an overall perspective of the designed fiber. The combination of terahertz (THz) wave and the orbital angular momentum (OAM) multiplexing technology can further improve the communication capacity. Compared to other outer cladding structures, the negative curvature structure has been proven to provide stronger confinement effect on electromagnetic waves. Here, we propose a novel polymer (COC TOPAS) fiber which consists a central hollow-core, annular region and single layer negative curvature circle tubes as outer cladding for terahertz OAM modes transmission. The mode map is established by mathematical analysis of cut-off conditions for the vector modes, and the excitation of high-order radial modes in the fiber is successfully suppressed. In addition, the effective refractive index, confinement loss, effective mode area, mode purity and dispersion characteristics of the fiber are investigated under the condition of ‘single mode’ operation in the frequency range of 2.0–3.0 THz.