• Photonics Research
  • Vol. 9, Issue 4, B81 (2021)
Xiao Wang1, Yufeng Qian1, JingJing Zhang1, Guangdong Ma1, Shupeng Zhao1, RuiFeng Liu1、*, Hongrong Li1, Pei Zhang1, Hong Gao1, Feng Huang2、3, and Fuli Li1
Author Affiliations
  • 1Shaanxi Province Key Laboratory of Quantum Information and Quantum Optoelectronic Devices, School of Physics, Xi’an Jiaotong University, Xi’an 710049, China
  • 2School of Mechanical Engineering and Automation, Fuzhou University, Fuzhou 350108, China
  • 3e-mail: huangf@fzu.edu.cn
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    DOI: 10.1364/PRJ.412965 Cite this Article Set citation alerts
    Xiao Wang, Yufeng Qian, JingJing Zhang, Guangdong Ma, Shupeng Zhao, RuiFeng Liu, Hongrong Li, Pei Zhang, Hong Gao, Feng Huang, Fuli Li. Learning to recognize misaligned hyperfine orbital angular momentum modes[J]. Photonics Research, 2021, 9(4): B81 Copy Citation Text show less

    Abstract

    Orbital angular momentum (OAM)-carrying beams have received extensive attention due to their high-dimensional characteristics in the context of free-space optical communication. However, accurate OAM mode recognition still suffers from reference misalignment of lateral displacement, beam waist size, and initial phase. Here we propose a deep-learning method to exquisitely recognize OAM modes under misalignment by using an alignment-free fractal multipoint interferometer. Our experiments achieve 98.35% recognizing accuracy when strong misalignment is added to hyperfine OAM modes whose Bures distance is 0.01. The maximum lateral displacement we added with respect to the perfectly on-axis beam is about ±0.5 beam waist size. This work offers a superstable proposal for OAM mode recognition in the application of free-space optical communication and allows an increase of the communication capacity.

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    xn=C1ncos(2πC22n),yn=C1nsin(2πC22n),

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    I|F[U(x,y)]|2,

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    |ψ=cosθ2|1+sinθ2eiϕ|1,

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    Xiao Wang, Yufeng Qian, JingJing Zhang, Guangdong Ma, Shupeng Zhao, RuiFeng Liu, Hongrong Li, Pei Zhang, Hong Gao, Feng Huang, Fuli Li. Learning to recognize misaligned hyperfine orbital angular momentum modes[J]. Photonics Research, 2021, 9(4): B81
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