Modal coupling and crosstalk due to turbulence and divergence on free space THz links using multiple orbital angular momentum beams
Abstract Orbital-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 explor...
| Main Authors: | , , , , , , , , , , , , , , , |
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| Format: | Article |
| Language: | English |
| Published: |
Nature Portfolio
2021-01-01
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| Series: | Scientific Reports |
| Online Access: | https://doi.org/10.1038/s41598-020-80179-3 |
| _version_ | 1831638045388963840 |
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| author | Zhe Zhao Runzhou Zhang Hao Song Kai Pang Ahmed Almaiman Huibin Zhou Haoqian Song Cong Liu Nanzhe Hu Xinzhou Su Amir Minoofar Hirofumi Sasaki Doohwan Lee Moshe Tur Andreas F. Molisch Alan E. Willner |
| author_facet | Zhe Zhao Runzhou Zhang Hao Song Kai Pang Ahmed Almaiman Huibin Zhou Haoqian Song Cong Liu Nanzhe Hu Xinzhou Su Amir Minoofar Hirofumi Sasaki Doohwan Lee Moshe Tur Andreas F. Molisch Alan E. Willner |
| author_sort | Zhe Zhao |
| collection | DOAJ |
| description | Abstract Orbital-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. |
| first_indexed | 2024-12-19T07:03:22Z |
| format | Article |
| id | doaj.art-172382cfc3754222b822b7df2041d5fc |
| institution | Directory Open Access Journal |
| issn | 2045-2322 |
| language | English |
| last_indexed | 2024-12-19T07:03:22Z |
| publishDate | 2021-01-01 |
| publisher | Nature Portfolio |
| record_format | Article |
| series | Scientific Reports |
| spelling | doaj.art-172382cfc3754222b822b7df2041d5fc2022-12-21T20:31:22ZengNature PortfolioScientific Reports2045-23222021-01-0111111210.1038/s41598-020-80179-3Modal coupling and crosstalk due to turbulence and divergence on free space THz links using multiple orbital angular momentum beamsZhe Zhao0Runzhou Zhang1Hao Song2Kai Pang3Ahmed Almaiman4Huibin Zhou5Haoqian Song6Cong Liu7Nanzhe Hu8Xinzhou Su9Amir Minoofar10Hirofumi Sasaki11Doohwan Lee12Moshe Tur13Andreas F. Molisch14Alan E. Willner15Department of Electrical Engineering, University of Southern CaliforniaDepartment of Electrical Engineering, University of Southern CaliforniaDepartment of Electrical Engineering, University of Southern CaliforniaDepartment of Electrical Engineering, University of Southern CaliforniaDepartment of Electrical Engineering, University of Southern CaliforniaDepartment of Electrical Engineering, University of Southern CaliforniaDepartment of Electrical Engineering, University of Southern CaliforniaDepartment of Electrical Engineering, University of Southern CaliforniaDepartment of Electrical Engineering, University of Southern CaliforniaDepartment of Electrical Engineering, University of Southern CaliforniaDepartment of Electrical Engineering, University of Southern CaliforniaNTT Network Innovation Laboratories, NTT CorporationNTT Network Innovation Laboratories, NTT CorporationSchool of Electrical Engineering, Tel Aviv UniversityDepartment of Electrical Engineering, University of Southern CaliforniaDepartment of Electrical Engineering, University of Southern CaliforniaAbstract Orbital-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.https://doi.org/10.1038/s41598-020-80179-3 |
| spellingShingle | Zhe Zhao Runzhou Zhang Hao Song Kai Pang Ahmed Almaiman Huibin Zhou Haoqian Song Cong Liu Nanzhe Hu Xinzhou Su Amir Minoofar Hirofumi Sasaki Doohwan Lee Moshe Tur Andreas F. Molisch Alan E. Willner Modal coupling and crosstalk due to turbulence and divergence on free space THz links using multiple orbital angular momentum beams Scientific Reports |
| title | Modal coupling and crosstalk due to turbulence and divergence on free space THz links using multiple orbital angular momentum beams |
| title_full | Modal coupling and crosstalk due to turbulence and divergence on free space THz links using multiple orbital angular momentum beams |
| title_fullStr | Modal coupling and crosstalk due to turbulence and divergence on free space THz links using multiple orbital angular momentum beams |
| title_full_unstemmed | Modal coupling and crosstalk due to turbulence and divergence on free space THz links using multiple orbital angular momentum beams |
| title_short | Modal coupling and crosstalk due to turbulence and divergence on free space THz links using multiple orbital angular momentum beams |
| title_sort | modal coupling and crosstalk due to turbulence and divergence on free space thz links using multiple orbital angular momentum beams |
| url | https://doi.org/10.1038/s41598-020-80179-3 |
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