SHEN Yuanxun,CHEN Xinjie,MA Xuelian.Improved neural network based demodulation of orbital angular momentum fiber-optic communication system[J].OPTICAL TECHNIQUE,2026,52(02):190-198.
SHEN Yuanxun,CHEN Xinjie,MA Xuelian.Improved neural network based demodulation of orbital angular momentum fiber-optic communication system[J].OPTICAL TECHNIQUE,2026,52(02):190-198.DOI:
Improved neural network based demodulation of orbital angular momentum fiber-optic communication system
Aiming at the problem of high bit error rate of orbital angular momentum(OAM) fiber-optic communication system
a demodulation method of orbital angular momentum based on improved neural network is proposed. For neural network architecture
the convolutional neural network is used to capture the local features of the OAM mode image
and the Swin Transformer is adopted to capture the global information of the OAM mode image
in order to enhance the discriminative power of the OAM mode image features. Consequently the accuracy of OAM demodulation is improved. For neural network training
the Generalized Mutual Information(GMI) is used to replace the traditional cross entropy loss
in order to enable the neural network not only to learn OAM mode recognition
but also to learn the probability distribution containing channel soft information
thus improving the error correction effect of Low Density Parity Check code. Experimental results show that
through improving the model architecture and model training
the proposed method effectively increases the demodulation accuracy of OAM mode
and the bit error rate of the OAM Fiber-optic communication system decreases significantly.
Tian Ye , Jiang Rui , Zhang Jiaming , et al . Perfect vertical grating coupler for multi-core fiber communication(Invited) [J ] . Laser & Optoelectronics Progress , 2025 , 62 ( 17 ): 330 — 335 .
Varshney A , Goyal V . Fiber optics communication: evolution of guided media [J ] . International Journal for Research in Applied Science and Engineering Technology , 2024 , 12 ( 1 ): 959 — 969 .
Qiao M , Wang Y , Li Z , et al . Novel dispersion and timing estimation for weakly-coupled OAM fiber transmission systems [J ] . IEEE Photonics Technology Letters , 2024 , 36 ( 14 ): 913 — 916 .
Liu J , Mo S , Xu Z , et al . High spectral-efficiency, ultra-low MIMO SDM transmission over a field-deployed multi-core OAM fiber [J ] . Photonics Research , 2025 , 13 ( 1 ): 18 — 30 .
Wang F , Gao R , Li Z , et al . OAM mode-division multiplexing IM/DD transmission at 4.32Tbit/s with a low-complexity adaptive-network-based fuzzy inference system nonlinear equalizer [J ] . Optics letters , 2024 , 49 ( 3 ): 430 — 433 .
Zhang J , Lin Z , Liu J . SDM transmission of orbital angular momentum mode channels over a multi-ring-core fibre [J ] . Nanophotonics , 2021 , 11 ( 4 ): 873 — 884 .
Liu J , Zhang J , Liu J , et al . 1-Pbps orbital angular momentum fibre-optic transmission [J ] . Light: Science&Applications , 2022 , 11 ( 8 ): 1823 — 1833 .
Bai Y , Lv H , Fu X , et al . Vortex beam: generation and detection of orbital angular momentum[Invited] [J ] . Chinese Optics Letters , 2022 , 20 ( 1 ): 133 — 147 .
Saitoh K , Hasegawa Y , Hirakawa K , et al . Measuring the orbital angular momentum of electron vortex beams using a forked grating [J ] . Physical Review Letters , 2013 , 111 ( 7 ): 74801 . 1—74801. 5 .
Lei T , Zhang M , Li Y , et al . Massive individual orbital angular momentum channels for multiplexing enabled by Dammann gratings [J ] . Light Science&Applications , 2015 , 4 ( 3 ): 257 . 1—257. 7 .
Fu S , Wang T , Zhang S , et al . Integrating 5×5 Dammann gratings to detect orbital angular momentum states of beams with the range of 24 to +24 [J ] . Applied Optics , 2016 , 55 ( 7 ): 1514 — 1520 .
Li B , Luan H , Li K , et al . Orbital angular momentum optical communications enhanced by artificial intelligence [J ] . Journal of Optics , 2022 , 24 ( 9 ), 094003 .
Hu J , Guo Z , Fu Y , et al . How convolutional-neural-network detects optical vortex scattering fields [J ] . Optics and Lasers in Engineering , 2023 , 160 ( 1 ): 107246 .
Zhu J , Fan M , Pu Y , et al . 1024-ary composite OAM shift keying for free-space optical communication system decoded by a two-step neural network [J ] . Optics Letters , 2023 , 48 ( 10 ): 2692 — 2695 .
Wang Z , Lai X , Huang H , et al . Recognizing the orbital angular momentum(OAM) of vortex beams from speckle patterns [J ] . Science China Physics , Mechanics & Astronomy, 2022 , 65 ( 4 ): 1 — 7 .
Liu Y , Zhang Z , Yu P , et al . Learning-enabled recovering scattered data from twisted light transmitted through a long standard multimode fiber [J ] . Applied Physics Letters , 2022 , 120 ( 13 ): 131101 .
Wang Z , Chen M , Wan M , et al . Coherent demodulated underwater wireless optical communication system based on convolutional neural network [J ] . Optics Communications , 2023 , 534 ( 1 ): 129316 .
Tian Q , Li Z , Hu K , et al . Turbo-coded 16-ary OAM shift keying FSO communication system combining the CNN-based adaptive demodulator [J ] . Optics Express , 2018 , 26 ( 21 ): 27849 — 27864 .
Ju Zhou , Wang Chen , Wang Kaihui , et al . 1000-km-Long Few-Mode Fiber Wavelength Division Multiplexing Transmission System with Net Rate of 32.768 Tbit/s [J ] . Acta Optica Sinica , 2023 , 43 ( 10 ): 38 — 45 .
Elmeadawy S , Shalaby H M H , Ismail N A , et al . A free space 16-ary OAM coded optical communication system based on chaotic-interleavingand CNNs [J ] . Applied Optics , 2020 , 59 ( 23 ): 6966 — 6976 .
Chen W , Hou Z , Yang L , et al . Performance investigation of an OAM-SK optical communication system based on a PCNN-LDPC under atmospheric turbulence [J ] . Optics Express , 2025 , 33 ( 3 ): 5369 — 5381 .
Jiang W , Zhao X , Fang F , et al . End-to-end learning of constellation shaping for optical fiber communication systems [J ] . IEEE Photonics Journal , 2023 , 15 ( 6 ): 1 — 7 .
Wang Qianfan , Yang Jiayi , Wang yinchu , et al . A review of coupled LDPC codes for streaming communications [J ] . Acta Electronica Sinica , 2024 , 52 ( 8 ): 2913 — 2932 .
Arbab A , Habibi A , Rabbani H , et al . From image to sequence: exploring vision transformers for optical coherence tomography classification [J ] . Journal of Medical Signals & Sensors , 2025 , 15 ( 6 ): 1 — 18 .
Liu Ze , Lin Yutong , Cao Yue , et al . Swin transformer: hierarchical vision transformer using shifted windows [C ] // 2021 IEEE/CVF International Conference on Computer Vision . Montreal, QC, Canada : IEEE , 2021 : 9992 — 10002 .
Alvarado A , Agrell E , Lavery D , et al . Replacing the soft-decision FEC limit paradigm in the design of optical communication systems [J ] . Journal of Lightwave Technology , 2015 , 33 ( 20 ): 4338 — 4352 .
Hu X Y , Eleftheriou E , Arnold D M , et al . Efficient implementations of the sum-product algorithm for decoding LDPC codes [C ] // IEEE Global Telecommunications Conference . San Antonio, TX, USA : IEEE , 2001 : 1036A — 1036E .