Atmospheric turbulence mitigation using spatial mode multiplexing and modified pulse position modulation in hybrid RF/FSO orbital-angular-momentum multiplexed based on MIMO wireless communications system

2019 ◽  
Vol 436 ◽  
pp. 197-208 ◽  
Author(s):  
Bedir B. Yousif ◽  
Ebrahim Eld. Elsayed ◽  
Mahmoud M. Alzalabani
Keyword(s):  
Angular Momentum ◽  
Wireless Communications ◽  
Atmospheric Turbulence ◽  
Orbital Angular Momentum ◽  
Pulse Position Modulation ◽  
Spatial Mode ◽  
Communications System

scholarly journals Modal coupling and crosstalk due to turbulence and divergence on free space THz links using multiple orbital angular momentum beams

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Zhe Zhao ◽  
Runzhou Zhang ◽  
Hao Song ◽  
Kai Pang ◽  
Ahmed Almaiman ◽  
...  
Keyword(s):  
Angular Momentum ◽  
Atmospheric Turbulence ◽  
Channel Capacity ◽  
Orbital Angular Momentum ◽  
Beam Waist ◽  
Modal Coupling ◽  
Divergence Effect ◽  
Power Leakage ◽  
Calm Weather ◽  
Bad Weather

AbstractOrbital-angular-momentum (OAM) multiplexing has been utilized to increase the channel capacity in both millimeter-wave and optical domains. Terahertz (THz) wireless communication is attracting increasing attention due to its broadband spectral resources. Thus, it might be valuable to explore the system performance of THz OAM links to further increase the channel capacity. In this paper, we study through simulations the fundamental system-degrading effects when using multiple OAM beams in THz communications links under atmospheric turbulence. We simulate and analyze the effects of divergence, turbulence, limited-size aperture, and misalignment on the signal power and crosstalk of THz OAM links. We find through simulations that the system-degrading effects are different in two scenarios with atmosphere turbulence: (a) when we consider the same strength of phasefront distortion, faster divergence (i.e., lower frequency; smaller beam waist) leads to higher power leakage from the transmitted mode to neighbouring modes; and (b) however, when we consider the same atmospheric turbulence, the divergence effect tends to affect the power leakage much less, and the power leakage increases as the frequency, beam waist, or OAM order increases. Simulation results show that: (i) the crosstalk to the neighbouring mode remains < − 15 dB for a 1-km link under calm weather, when we transmit OAM + 4 at 0.5 THz with a beam waist of 1 m; (ii) for the 3-OAM-multiplexed THz links, the signal-to-interference ratio (SIR) increases by ~ 5–7 dB if the mode spacing increases by 1, and SIR decreases with the multiplexed mode number; and (iii) limited aperture size and misalignment lead to power leakage to other modes under calm weather, while it tends to be unobtrusive under bad weather.

A new method of calculating the orbital angular momentum spectra of Laguerre–Gaussian beams in channels with atmospheric turbulence

2017 ◽  
Vol 26 (11) ◽  
pp. 114207 ◽  
Author(s):  
Xiao-zhou Cui ◽  
Xiao-li Yin ◽  
Huan Chang ◽  
Zhi-chao Zhang ◽  
Yong-jun Wang ◽  
...  
Keyword(s):  
Angular Momentum ◽  
Atmospheric Turbulence ◽  
Orbital Angular Momentum ◽  
New Method ◽  
Gaussian Beams ◽  
Momentum Spectra

Orbital-Angular-Momentum-Encoded Measurement-Device-Independent Quantum Key Distributions Under Atmospheric Turbulence

2018 ◽  
Vol 38 (12) ◽  
pp. 1227002
Author(s):  
朱卓丹 Zhu Zhuodan ◽  
赵尚弘 Zhao Shanghong ◽  
谷文苑 Gu Wenyuan ◽  
刘菁 Liu Jing ◽  
孙祥祥 Sun Xiangxiang
Keyword(s):  
Angular Momentum ◽  
Atmospheric Turbulence ◽  
Orbital Angular Momentum ◽  
Measurement Device ◽  
Measurement Device Independent

scholarly journals Convolutional Neural Network Based Atmospheric Turbulence Compensation for Optical Orbital Angular Momentum Multiplexing

2020 ◽  
Vol 38 (7) ◽  
pp. 1712-1721
Author(s):  
Wenjie Xiong ◽  
Peipei Wang ◽  
Menglong Cheng ◽  
Junmin Liu ◽  
Yanliang He ◽  
...  
Keyword(s):  
Neural Network ◽  
Angular Momentum ◽  
Convolutional Neural Network ◽  
Atmospheric Turbulence ◽  
Orbital Angular Momentum

scholarly journals Liquid crystal spatial-mode converters for the orbital angular momentum of light

2013 ◽  
Vol 15 (2) ◽  
pp. 025406 ◽  
Author(s):  
Sergei Slussarenko ◽  
Bruno Piccirillo ◽  
Vladimir Chigrinov ◽  
Lorenzo Marrucci ◽  
Enrico Santamato
Keyword(s):  
Angular Momentum ◽  
Liquid Crystal ◽  
Orbital Angular Momentum ◽  
Spatial Mode ◽  
Mode Converters
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