Analysis of the orbital angular momentum spectrum for Laguerre–Gaussian beams under moderate-to-strong marine-atmospheric turbulent channels

• Published in: Optics communications 2018-11, Vol.426, p.471-476
• Main Authors: Cui, Xiao-zhou, Yin, Xiao-li, Chang, Huan, Sun, Zhi-wen, Wang, Yong-jun, Tian, Qing-hua, Wu, Guo-hua, Xin, Xiang-jun
• Format: Article
• Language: English
• Subjects: Free-space optical (FSO) communications; Marine-atmospheric turbulence; Orbital angular momentum (OAM) spectrum
• ISSN: 0030-4018; 1873-0310
• DOI: 10.1016/j.optcom.2018.05.061

Free-space optical (FSO) communication based on orbital angular momentum (OAM) can be used to enhance the capacity of systems for vessel-to-vessel or ship-to-aircraft communication. Studying the OAM spectrum is important for analyzing the performance of FSO-OAM communication systems under marine-atmosphere channels. This study offers a new, concise form for the OAM spectrum for Laguerre–Gaussian (LG) beams propagating under moderate-to-strong marine-atmospheric turbulent channels with high accuracy. We use a concise expression to analytically investigate the rules governing the variation in the OAM spectrum versus OAM number, distance, refractive-index structure parameter, and wavelength. We demonstrate that broadening of the OAM spectrum caused by marine-atmospheric channels can be analytically studied based on a simplified expression. The results indicate that an increase in the transmitted OAM number, distance and refractive-index structure parameter exacerbates broadening of the OAM spectrum and that using a larger wavelength relieves such broadening. This data contributes to the analysis of FSO-OAM multiplexing communication systems under marine-atmospheric turbulent channels and the design of future over-the-sea communication systems.