Review
Nanoscience & Nanotechnology
Alan E. E. Willner, Xinzhou Su, Hao Song, Huibin Zhou, Kaiheng Zou
Summary: There is a growing interest in using multiple multiplexed orthogonal orbital angular momentum (OAM) beams to increase data capacity in communication systems. This article discusses the use of pixel-array-based metasurfaces as OAM transmitters and receivers for mode division multiplexing (MDM) communications in the near-infrared (NIR) and terahertz (THz) regimes.
Article
Optics
Zhibing Liu, Shecheng Gao, Zhaoyu Lai, Yuru Li, Zhaohuan Ao, Jinpei Li, Jiajing Tu, Yanxiong Wu, Weiping Liu, Zhaohui Li
Summary: By utilizing an optical diffraction neural network, a low-crosstalk OAM de/multiplexer operating in the full C+L band is developed. The device supports 16 OAM modes with low insertion loss and intermode crosstalk. This research has great application prospects for mode de/multiplexers and mode division multiplexing communication systems.
LASER & PHOTONICS REVIEWS
(2023)
Article
Engineering, Electrical & Electronic
Xinzhou Su, Hao Song, Huibin Zhou, Kaiheng Zou, Yuxiang Duan, Narek Karapetyan, Runzhou Zhang, Amir Minoofar, Haoqian Song, Kai Pang, Shlomo Zach, Andreas F. Molisch, Moshe Tur, Alan E. Willner
Summary: We demonstrate a THz integrated circuit that can generate and multiplex multiple data-carrying OAM beams using a pixel-array-based OAM mode converter. The device includes coupling spikes to couple THz signals to the circuit, mode expansion structures to match the OAM mode converter, and a pixel-array-based OAM mode converter to emit and multiplex OAM beams with different mode orders. The generated OAM order depends on the input port.
JOURNAL OF LIGHTWAVE TECHNOLOGY
(2023)
Article
Engineering, Electrical & Electronic
Nan Li, Shilie Zheng, Hang Yang, Tong He, Donghui Shen, Hongqi Zhang, Zuomin Yang, Zhidong Lyu, Lu Zhang, Xianbin Yu
Summary: In this article, a novel broadband dual-polarized reflective metasurface is proposed to enable the multiplexing of orbital angular momentum (OAM) and polarization in the terahertz (THz) region. The metasurface can generate two coaxially propagating OAM beams with distinct modes for each polarization. A THz wireless communication system was demonstrated using the metasurface, achieving an aggregate 48 Gbit/s data transmission with a low bit error rate (BER) below 3.8e-3. This work showcases the feasibility of using metasurfaces for multidimensional multiplexing in ultrahigh-speed THz communication systems.
IEEE TRANSACTIONS ON MICROWAVE THEORY AND TECHNIQUES
(2023)
Article
Multidisciplinary Sciences
Ali Ali, Mohsen Khalily, Tim Brown, Rahim Tafazolli
Summary: This article investigates the unexplored potentials of vortices or orbital angular momentum (OAM) beams using the low-cost and high-gain dielectric reflectarray antennas (RAs) at the terahertz band. It proposes a paradigm to enable 3D beam-steering or OAM multiplexing by a single structure via tilted OAM beams. The proposed paradigm can be utilized to produce RAs with beam-steering or OAM multiplexing capabilities as candidates for THz indoor communications.
Article
Engineering, Electrical & Electronic
Hang Yang, Shilie Zheng, Hongqi Zhang, Nan Li, Donghui Shen, Tong He, Zuomin Yang, Zhidong Lyu, Xianbin Yu
Summary: In this article, a THz-OAM wireless communication system operating at 100 GHz based on a transmissive metasurface is proposed for the first time. The system demonstrates the generation of two high mode purity OAM beams with excellent orthogonality, which are used as two independent communication channels to achieve a data rate of 10 Gbit/s. This work validates the feasibility of multiplexing metasurface and highlights the potential of THz-OAM wireless communication systems for future large capacity wireless services.
IEEE TRANSACTIONS ON ANTENNAS AND PROPAGATION
(2023)
Article
Materials Science, Multidisciplinary
Chengtian Song, Mengqian Deng, Xiaowen Wang, Yonghui Jiao, Bohu Liu
Summary: With the development of high-speed THz communications, this study proposes a reflective broadband metasurface that harnesses the orbital angular momentum (OAM) of electromagnetic waves. Through quantitative analysis of the metasurface elements, a reflective broadband element surface array with an ordered arrangement of 3-bit elements is designed. The simulation results demonstrate that the metasurface structure can efficiently convert linearly polarized waves into vortex beams with an efficiency exceeding 85% and achieve high-purity OAM beam acquisition. Moreover, the metasurface structure is simple to implement and can be easily integrated with photoelectric circuits, making it ideal for ultrahigh-speed THz communications.
OPTICAL MATERIALS EXPRESS
(2023)
Article
Multidisciplinary Sciences
Cormac McDonnell, Junhong Deng, Symeon Sideris, Tal Ellenbogen, Guixin Li
Summary: The use of broadband THz emitters based on Pancharatnam-Berry phase nonlinear metasurfaces allows for precise control and tuning of THz waves.
NATURE COMMUNICATIONS
(2021)
Article
Engineering, Electrical & Electronic
Xiaoyuan He, Li Deng, Botao Feng, Kwok L. Chung, Liang Yin, Lijie Chen
Summary: Angular momentum (AM) multiplexing technique provides multiple information channels for electromagnetic waves (EMWs) modulation at the same frequency, improving spectrum efficiency effectively. Among AM multiplexing techniques, the patch antenna has the advantage of minimization, simple feeding circuits, and easy integration. Nevertheless, limited reports provide theoretical guidance for designing AM multiplexing patch antennas.
IEEE TRANSACTIONS ON ANTENNAS AND PROPAGATION
(2023)
Article
Optics
Xiaohui Wang, Yang Wang, Shuai Mao, Yongze Yu, Haoyu Gu, Dongdong Deng, Yingxiong Song, Fufei Pang, Liyun Zhuang, Song Yang, Xiaofeng He, Dandan Wei, Yudong Yang
Summary: To address the upcoming famine of channel capacity, optical orbital angular momentum (OAM) has been proposed for space-division multiplexing (SDM). However, atmospheric turbulence (AT) severely impacts the performance of OAM-based free-space optical communication (FSOC) due to crosstalk induced by distorted helical phase. A synthesizing-crosstalk method is proposed to mitigate AT by using an OAM-probe beam (OPB) that has the same mode as the propagated OAM-data beam (ODB). Experimental results show that the proposed scheme improves the bit error rate (BER) and constellation plot (CP) of the OAM channels under different AT conditions, making it feasible for future OAM-based FSOC.
OPTICS AND LASER TECHNOLOGY
(2023)
Article
Engineering, Electrical & Electronic
Xi Zhang, Jian Wang
Summary: This paper proposes a novel ring-core fiber design that supports up to 5 orbital angular momentum mode groups with low crosstalk. The simulated results show that the designed fiber has low crosstalk between high-order adjacent mode groups and good bending characteristics. It also exhibits ultra-broadband performance ranging from 1530 nm to 1625 nm. This fiber design could be used for small-scale multiple-input multiple-output digital signal processing or combined with wavelength-division multiplexing for inter-group mode multiplexing transmission.
IEEE JOURNAL OF QUANTUM ELECTRONICS
(2023)
Article
Optics
A. Curcio, S. Mou, L. Palumbo, S. Lupi, M. Petrarca
Summary: In this theoretical study, the transduction of orbital angular momentum (OAM) from infrared pump lasers to the THz domain is investigated. The selection rules for OAM transduction differ between optical rectification and difference frequency generation, with the former following a strict rule of l = 0 and the latter allowing a range of values for the difference Delta l. The degree of diffraction resulting from tightly focused pump beams also influences the OAM values in THz generation.
News Item
Optics
Philippe St-Jean
Summary: This paper presents a novel solid-state laser that can generate a large array of phase-locked optical vortices with tunable orbital angular momentum.
News Item
Optics
Spencer W. Jolly
Summary: A diffractive axicon can create intricate connections between topological charges and frequencies of ultrashort laser pulses, resulting in a diverse range of coiled light structures.
Article
Physics, Multidisciplinary
Yangyang Fu, Yuan Tian, Xiao Li, Shili Yang, Youwen Liu, Yadong Xu, Minghui Lu
Summary: In this study, a new method for achieving robust asymmetric generation of acoustic vortex field through dual-layer metasurfaces is introduced. This is achieved by controlling the intrinsic topologic charges and the parity of geometry design. The underlying physics is contributed to the one-way process of orbital angular momentum transition ensured by the broken spatial symmetry and the external topologic charge from the vortex diffraction. The novel phenomenon is experimentally demonstrated, providing new routes to manipulate the asymmetric response of vortex fields and potential applications in passive OAM-based diodes.
PHYSICAL REVIEW LETTERS
(2022)
Article
Optics
Kaiheng Zou, Hao Song, Zhe Zhao, Kai Pang, Amir Minoofar, Xinzhou Su, Huibin Zhou, Runzhou Zhang, Haoqian Song, Nanzhe Hu, Cong Liu, Moshe Tur, Alan E. Willner
Summary: This study simulates the generation of space-time light sheets by combining multiple frequency comb lines carrying multiple Laguerre-Gaussian modes. The resulting light sheets have controllable group velocity and reduced diffraction due to the correlation relationship between the spatial and temporal domain. Variation in the propagation distance and number of modes affects the deviation of the group velocity from the designed value. Additionally, the reduced diffraction is characterized by the ratio of the propagation distance over which the axial intensity is reduced by half.
OPTICS COMMUNICATIONS
(2022)
Article
Optics
Hao Song, Runzhou Zhang, Huibin Zhou, Xinzhou Su, Kaiheng Zou, Yuxiang Duan, Narek Karapetyan, Haoquin Song, Kai Pang, Nanzhe Hu, Amir Minoofar, Moshe Tur, Alan E. Willner
Summary: The study demonstrates a turbulence-resilient free-space optical link using a photodetector array, achieving efficient mixing of data and pilot beams for improved data recovery quality.
Article
Engineering, Electrical & Electronic
Xinzhou Su, Hao Song, Huibin Zhou, Kaiheng Zou, Yuxiang Duan, Narek Karapetyan, Runzhou Zhang, Amir Minoofar, Haoqian Song, Kai Pang, Shlomo Zach, Andreas F. Molisch, Moshe Tur, Alan E. Willner
Summary: We demonstrate a THz integrated circuit that can generate and multiplex multiple data-carrying OAM beams using a pixel-array-based OAM mode converter. The device includes coupling spikes to couple THz signals to the circuit, mode expansion structures to match the OAM mode converter, and a pixel-array-based OAM mode converter to emit and multiplex OAM beams with different mode orders. The generated OAM order depends on the input port.
JOURNAL OF LIGHTWAVE TECHNOLOGY
(2023)
Article
Optics
Runzhou Zhang, Kaiheng Zou, Xinzhou Su, Yuxiang Duan, Huibin Zhou, Haoqian Song, Hao Song, Amir Minoofar, Nanzhe Hu, Kai Pang, Robert W. Boyd, Moshe Tur, Alan E. Willner
Summary: Free-space-optical (FSO) communications benefit from power-efficient modulation formats and detection methods. Differential-phase-shift-keying (DPSK) is more optical-power efficient than intensity modulation when detecting both output arms in the receiver. However, turbulence-induced modal coupling loss can cause high power loss in the differential receiver. In this study, a turbulence-resilient DPSK FSO link is demonstrated, and the turbulence-induced modal coupling loss is compensated by optoelectronic (O/E) mixing of higher-order spatial modes.
OPTICS COMMUNICATIONS
(2023)
Article
Engineering, Electrical & Electronic
Alan E. Willner, Hao Song, Kaiheng Zou, Huibin Zhou, Xinzhou Su
Summary: This review article discusses the growing interest in structured light, particularly in orbital angular momentum (OAM) beams, and explores their use in high-capacity communication systems. It covers various aspects including basic multiplexing and encoding links, technical hurdles, mitigation approaches, and advanced topics such as encoded quantum communications and novel beams.
JOURNAL OF LIGHTWAVE TECHNOLOGY
(2023)
Article
Engineering, Electrical & Electronic
Huibin Zhou, Runzhou Zhang, Xinzhou Su, Yuxiang Duan, Haoqian Song, Hao Song, Kaiheng Zou, Robert W. Boyd, Moshe Tur, Alan E. Willner
Summary: The utilization efficiency of the detector's bandwidth can be increased by using self-homodyne detection in a pilot-assisted FSO link, which also improves the optical-to-electrical mixing efficiency under turbulent conditions.
JOURNAL OF LIGHTWAVE TECHNOLOGY
(2023)
Article
Optics
Hao Song, Kaiheng Zou, Huibin Zhou, Narek Karapetyan, Amir Minoofar, Xinzhou Su, Ahmed Almaiman, Jonathan L. Habif, Moshe Tur, Alan E. Willner
Summary: This paper experimentally demonstrates an optics-based half-adder for two 4-phase-shift-keying (4-PSK) data channels using nonlinear wave mixing. The half-adder has high conversion efficiency and low optical signal-to-noise ratio (OSNR).
Article
Optics
Huibin Zhou, Yuxiang Duan, Hao Song, Xinzhou Su, Zhe Zhao, Kaiheng Zou, Haoqian Song, Runzhou Zhang, Robert W. Boyd, Moshe Tur, Alan E. Willner
Summary: The use of temporal phase-based data encoding and coherent detection with a local oscillator (LO) in free-space optical (FSO) links provides various performance advantages. However, atmospheric turbulence can degrade the mixing efficiency between the data beam and a Gaussian LO. In this study, we demonstrate automatic turbulence mitigation in a 2-Gbit/s quadrature-phase-shift-keying (QPSK) coherent FSO link using degenerate four-wave-mixing (DFWM)-based phase conjugation and fiber-coupled data modulation. Compared to a coherent FSO link without mitigation, our approach achieves higher LO-data mixing efficiency and improved error vector magnitude (EVM) performance under various turbulence realizations.
Review
Nanoscience & Nanotechnology
Alan E. E. Willner, Xinzhou Su, Hao Song, Huibin Zhou, Kaiheng Zou
Summary: There is a growing interest in using multiple multiplexed orthogonal orbital angular momentum (OAM) beams to increase data capacity in communication systems. This article discusses the use of pixel-array-based metasurfaces as OAM transmitters and receivers for mode division multiplexing (MDM) communications in the near-infrared (NIR) and terahertz (THz) regimes.
Article
Optics
Alan E. Willner, Kaiheng Zou, Kai Pang, Hao Song, Huibin Zhou, Amir Minoofar, Xinzhou Su
Summary: In this paper, the use of wavelength division multiplexing (WDM) and orbital angular momentum (OAM)-based mode division multiplexing (MDM) in mid-infrared (mid-IR) free-space optical (FSO) communications is reviewed. The effects of mid-IR wavelengths in FSO communication links are introduced, and the methods to modulate and detect signals on mid-IR wavelengths are discussed. The techniques of WDM and OAM-based MDM in the mid-IR are then introduced. Finally, the performance of a mid-IR FSO communication system combining both multiplexing techniques is focused on.
OPTICS COMMUNICATIONS
(2023)
Article
Optics
Haoqian Song, Runzhou Zhang, Huibin Zhou, Kaiheng Zou, Nanzhe Hu, Xinzhou Su, Hao Song, Kai Pang, Yuxiang Duan, Daeyoung Park, Brittany Lynn, Greg Gbur, Aristide Dogariu, Richard J. Watkins, Jerome K. Miller, Eric Johnson, Moshe Tur, Alan E. Willner
Summary: When a Laguerre Gaussian (LG) beam passes through the air-water interface, it can experience beam distortion and beam wandering, resulting in modal power coupling. The increase in water curvature frequency and aerosol attenuation leads to stronger modal coupling to adjacent modes. Beam distortion and beam wandering contribute to modal coupling, with beam distortion possibly causing higher modal coupling under certain conditions. Furthermore, a demonstration of a 1-Gbit/s on-off-keying (OOK) link carried by a single LG11 beam under aerosol and curvature effects is presented.
OPTICS COMMUNICATIONS
(2023)
Article
Multidisciplinary Sciences
Huibin Zhou, Xinzhou Su, Yuxiang Duan, Hao Song, Kaiheng Zou, Runzhou Zhang, Haoqian Song, Nanzhe Hu, Moshe Tur, Alan E. Willner
Summary: Atmospheric turbulence can cause critical problems in various applications. To effectively mitigate turbulence, it is important to have knowledge of turbulence strength at different distances. This study explores turbulence probing using sequentially transmitted longitudinally structured beams, which can potentially probe longer distances or require smaller transceivers compared to previous techniques.
NATURE COMMUNICATIONS
(2023)
Proceedings Paper
Optics
Huibin Zhou, Runzhou Zhang, Xinzhou Su, Yuxiang Duan, Haoqian Song, Hao Song, Kaiheng Zou, Robert W. Boyd, Moshe Tur, Alan E. Willner
Summary: We experimentally demonstrate a turbulence-resilient 12-Gbit/s 16-QAM FSO link using pilot-assisted self-homodyne detection instead of heterodyne detection. The results show that the link remains stable under 400 random turbulence realizations, and there is an improvement of approximately 20 dB in the optical-to-electrical mixing efficiency compared to conventional LO-based coherent detection.
2022 EUROPEAN CONFERENCE ON OPTICAL COMMUNICATION (ECOC)
(2022)
Proceedings Paper
Engineering, Electrical & Electronic
Hao Song, Runzhou Zhang, Huibin Zhou, Xinzhou Su, Kaiheng Zou, Yuxiang Duan, Haoqian Song, Kai Pang, Nanzhe Hu, Narek Karapetyan, Amir Minoofar, Moshe Tur, Alan E. Willner
Summary: In this study, a turbulence-resilient 4 Gbit/s 16-QAM self-coherent free-space optical link is demonstrated using a pilot tone. The overall bandwidth under turbulence is potentially increased by using an array of smaller photodiodes (D/r(0) = approximately 8.4).
2022 OPTICAL FIBER COMMUNICATIONS CONFERENCE AND EXHIBITION (OFC)
(2022)
Proceedings Paper
Engineering, Electrical & Electronic
Haoqian Song, Runzhou Zhang, Huibin Zhou, Kaiheng Zou, Nanzhe Hu, Xinzhou Su, Hao Song, Kai Pang, Yuxiang Duan, Daeyoung Park, Brittany Lynn, Greg Gbur, Aristide Dogariu, Richard J. Watkins, Jerome K. Miller, Eric Johnson, Moshe Tur, Alan E. Willner
Summary: We experimentally investigate the 2-D modal power coupling of LG(11) and HG(11) beams under dynamic aerosol and water curvature, and demonstrate a 1-Gbit/s LG(11) Free Space Optics (FSO) link with a penalty of about 3 dB compared to no-effect cases.
2022 OPTICAL FIBER COMMUNICATIONS CONFERENCE AND EXHIBITION (OFC)
(2022)