Distortion Compensation for Orbital Angular Momentum Beams: From Probing to Deep Learning

Guo, Yingchi; Li, Lang; Wang, Jiaqi; Gao, Chunqing; Fu, Shiyao

doi:10.1109/jlt.2022.3218828

Cited by 10 publications

(3 citation statements)

References 132 publications

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“…In fact, for long-distance and high-speed optical communication, AT can cause rapid attenuation of the optical signal and random phase perturbation, which results in reduced accuracy in identifying the OAM states at the receiver and increased the BER. To overcome the influence of AT, adaptive optical techniques , are commonly used to improve the quality and efficiency. In addition, intelligent algorithms based on neural networks can also be used to enhance the robustness of multiplexed vortex beam transmission.…”

Section: Discussionmentioning

confidence: 99%

Orbital Angular Momentum Neural Communications for 1-to-40 Multicasting with 16-Ary Shift Keying

Meng

Luan

et al. 2023

ACS Photonics

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Orbital angular momentum (OAM) can be employed as information carrier in optical communications, which include OAM multicasting where separate OAM beams are produced to construct one-to-many links, and OAM shift keying where different OAM states are used for symbol coding. However, it remains a significant challenge to achieve a hyperscale OAM multicasting with OAM shift keying simultaneously, due to the deviation of complex OAM spectral components at the transmitter. Here, we demonstrate the concept of OAM neural communication by developing a high-precision, noniterative and ultra-multi-user optical communication coding scheme based on a deep-learning U-net neural network. The neural network is trained with only small datasets (there are 10 10 datasets in total, but only 10 3 datasets are used) to predict the OAM spectrum of ultra-high precision, with the mean square error (MSE) evaluated as 0.02 in all OAM channels. As a proof of concept, we experimentally demonstrate 1-to-40 multicasting with 16-ary shift keying in OAM communication. After a 3-meter free space transmission, we realize the encoding and decoding of 40 images with 16 gray values with a BER of 0. Moreover, our artificial intelligence-based methodology can be extended to manipulate three-dimensional OAM pixel arrays for holographic display and optical trapping.

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Section: Discussionmentioning

confidence: 99%

Orbital Angular Momentum Neural Communications for 1-to-40 Multicasting with 16-Ary Shift Keying

Meng

Luan

et al. 2023

ACS Photonics

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“…These factors will lead to insufficient signal power and a poorer signal-to-noise ratio at the terminals. More seriously, due to the inhomogeneities of the atmospheric temperature and pressure, the random variations of the refractive index along the transmission path result in the phase distortion of the OAM mode, which in turn induces the portion of transmitted OAM mode to be coupled to adjacent OAM modes, generating the so-called mode crosstalk [15][16][17][18]. The quality of OAM-based FSOC will be seriously affected.…”

Section: Introductionmentioning

confidence: 99%

“…This method requires redesigning the transmitter, which will increase the complexity of the system and degrade its flexibility. At the same time, various approaches for mitigating mode crosstalk have been reported [18]. One possible approach is adaptive optics [24][25][26], whose working principle is to measure the distorted phase of OAM mode induced by atmospheric turbulence first, and then an error correction phase is introduced to eliminate the influence of atmospheric turbulence.…”

Section: Introductionmentioning

confidence: 99%

Atmospheric Turbulence Effects on the Performance of Orbital Angular Momentum Multiplexed Free-Space Optical Links Using Coherent Beam Combining

Fan

Gao

et al. 2023

Photonics

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Atmospheric effects including absorption and scattering, and turbulence could introduce signal power loss and severe mode crosstalk for the orbital angular momentum (OAM)-based free-space optical communication (FSOC). Therefore, it is of great significance to simultaneously increase signal power and mitigate mode crosstalk. In this paper, for the OAM beam from a coherent laser array with a discrete vortex (CLA-DV) based on coherent beam combining, we investigate its propagation characteristics by employing theoretical derivation and the random phase screens simulation in atmospheric propagation, respectively. The probability density and OAM spectrum are given and compared for CLA-DV and Gaussian vortex beam. The results demonstrate that the Gaussian vortex beam exhibits smaller mode crosstalk under weak atmospheric turbulence conditions, while CLA-DV shows a good performance on crosstalk mitigation for strong atmospheric turbulence conditions in long-distance links. Furthermore, with a specially designed radial phase-locked Gaussian laser array composed of two orthogonal polarized coherent laser arrays carrying different OAM states, a scheme of optical communication system possessing simultaneously polarization-division multiplexing and OAM multiplexing is proposed. The normalized energy weight matrices of all 16 non-zeroth-order OAM modes are numerically calculated. To verify the feasibility of the proposed scheme, the performance of an eight-bit grayscale Lena image facing various atmosphere turbulences is evaluated. The quality of transmitted images becomes worse with the turbulence strength and transmission distance increase, which is confirmed by the trend of average optical signal error rates. This work will provide theoretical insight for improving the performance of OAM-based FSOC under scattering conditions.

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Advanced-prediction compensation of distorted vortex beams in dynamic turbulence using a Pre-correction network

Zhao

Meng

et al. 2023

Optics and Lasers in Engineering

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Distortion Compensation for Orbital Angular Momentum Beams: From Probing to Deep Learning

Cited by 10 publications

References 132 publications

Orbital Angular Momentum Neural Communications for 1-to-40 Multicasting with 16-Ary Shift Keying

Orbital Angular Momentum Neural Communications for 1-to-40 Multicasting with 16-Ary Shift Keying

Atmospheric Turbulence Effects on the Performance of Orbital Angular Momentum Multiplexed Free-Space Optical Links Using Coherent Beam Combining

Advanced-prediction compensation of distorted vortex beams in dynamic turbulence using a Pre-correction network

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