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Generation of polarization-multiplexed terahertz orbital angular momentum combs via all-silicon metasurfaces

Light(advanced Manufacturing) 2024年第3期5卷 120-129页

作者： Ming-Zhe Chong Yiwen Zhou Zong-Kun Zhang Jin Zhao Yue-Yi Zhang Chong-Qi Zhang Xiaofei Zang Chao-Hai Du Pu-Kun Liu Ming-Yao Xia School of Electronics Peking UniversityBeijing 100871China Terahertz Technology Innovation Research Institute and Shanghai Key Lab of Modern Optical SystemUniversity of Shanghai for Science and TechnologyNo.516 Jun Gong RoadShanghai 200093China State Key Laboratory of Advanced Optical Communication Systems and Networks School of ElectronicsPeking UniversityBeijing 100871China

Electromagnetic waves carrying orbital angular momentum(OAM),namely OAM beams,are important in various fields including optics,communications,and quantum ***,most current schemes can only generate single or several simple OAM ***-mode OAM beams are rarely *** paper proposes a scheme to design metasurfaces that can generate multiple polarization-multiplexed OAM modes with equal intervals and intensities(i.e.,OAM combs)working in the terahertz(THz)*** a proof of concept,we first design a metasurface to generate a pair of polarization-multiplexed OAM combs with arbitrary mode ***,another metasurface is proposed to realize a pair of polarization-multiplexed OAM combs with arbitrary locations and intervals in the OAM *** results agree well with full-wave simulations,verifying a great performance of OAM combs *** method may provide a new solution to designing high-capacity THz devices used in multi-mode communication systems.

关键词： Metasurfaces Terahertz Orbital angular momentum comb Polarization multiplexing

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Fast and Accurate Estimation of MDL - Induced SNR Penalty in SDM Link with Non-Uniform Noise Loading

Fast and Accurate Estimation of MDL - Induced SNR Penalty in...

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Asia communications and Photonics Conference and Exhibition (ACP)

作者： Tonghui Ji Qi Wu Zhaopeng Xu Honglin Ji Yu Yang Lulu Liu Shangcheng Wang Zhongliang Sun Junpeng Liang Linsheng Fan Jianwei Tang Jinlong Wei Juhao Li Weisheng Hu Pengcheng Laboratory Shenzhen China State Key Lab of Advanced Optical Communication System and Networks Shanghai Jiao Tong University Shanghai China State Key Laboratory of Advanced Optical Communication Systems & Networks Peking University Beijing China

We propose a fast and accurate estimation method of MDL-induced SNR penalty with non-uniform noise loading in SDM link. The proposed approach substantially saves the time cost while maintaining an estimation error wit... 详细信息

ISBN: (数字)9798350379266

ISBN: (纸本)9798350379273

关键词： optical losses Costs Accuracy Simulation Loading Propagation losses optical fiber communication Numerical models Signal to noise ratio Photonics

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Accurate and broadband manipulations of harmonic amplitudes and phases to reach 256 QAM millimeter-wave wireless communications by time-domain digital coding metasurface

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National Science Review 2022年第1期9卷 36-46页

作者： Ming Zheng Chen Wankai Tang Jun Yan Dai Jun Chen Ke Lei Zhang Cheng Zhang Jin Yang Lianlin Li Qiang Cheng Shi Jin Tie Jun Cui Institute of Electromagnetic Space Southeast University State Key Laboratory of Terahertz and Millimeter Waves City University of Hong Kong State Key Laboratory of Advanced Optical Communication Systems and Networks Department of Electronics Peking University National Mobile Communications Research Laboratory Southeast University State Key Laboratory of Millimeter Waves Southeast University Center of Intelligent Metamaterials Pazhou Laboratory

We propose a theoretical mechanism and new coding strategy to realize extremely accurate manipulations of nonlinear electromagnetic harmonics in ultrawide frequency band based on a time-domain digital coding metasurface(TDCM).Using the proposed mechanism and coding strategy,we design and fabricate a millimeter-wave(mmWave) TDCM,which is composed of reprogrammable meta-atoms embedded with positive-intrinsic-negative *** controlling the duty ratios and time delays of the digital coding sequences loaded on a TDCM,experimental results show that both amplitudes and phases of different harmonics can be engineered at will simultaneously and precisely in broad frequency band from 22 to33 GHz,even when the coding states are imperfect,which is in good agreement with theoretical *** on the fabricated high-performance TDCM,we further propose and experimentally realize a large-capacity mmWave wireless communication system,where 256 quadrature amplitude modulation,along with other schemes,is *** new wireless communication system has a much simpler architecture than the currently used mmWave wireless systems,and hence can significantly reduce the hardware *** believe that the proposed method and system architecture can find vast application in future mmWave and terahertz-wave wireless communication and radar systems.

关键词： metasurface time-domain digital coding accurate and broadband harmonic control 256 QAM millimeter-wave wireless communications

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Multi-Task Learning: Towards Low-Complexity Neural Network Nonlinearity Compensation in Coherent optical systems

Multi-Task Learning: Towards Low-Complexity Neural Network N...

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Asia communications and Photonics Conference and Exhibition (ACP)

We propose multi-task learning based NN equalization for nonlinearity compensation in coherent optical system. Compared with conventional NN equalization, 30% complexity reduction is achieved in an 800-Gb/s PDM-16QAM ... 详细信息

ISBN: (数字)9798350379266

ISBN: (纸本)9798350379273

关键词： Q-factor Equalizers Symbols Artificial neural networks optical computing optical fiber networks Multitasking Real-time systems Complexity theory Photonics

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Spontaneous symmetry breaking in nonlinear binary periodic systems

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Physical Review A 2024年第4期110卷 043513页

作者： Ruihan Peng Qidong Fu Yejia Chen Weidong Luo Changming Huang Fangwei Ye State Key Laboratory of Advanced Optical Communication Systems and Networks School of Physics and Astronomy School of Physics and Astronomy Department of Physics

Spontaneous symmetry breaking (SSB) occurs when modes of asymmetric profile appear in a symmetric, double-well potential, due to the nonlinearity of the potential exceeding a critical value. In this study, we examine SSB in a periodic potential where the unit cell itself is a symmetric double well, in both one-dimensional (1D) and two-dimensional (2D) periodic systems. Using the tight-binding model, we derive the analytical form that predicts the critical power at which SSB occurs for both 1D and 2D systems. The results show that the critical power depends significantly on the quasimomentum of the Bloch mode, and as the modulus of momentum increases, the SSB threshold decreases rapidly, potentially dropping to zero. These analytical findings are supported by numerical nonlinear eigenmode analysis and direct propagation simulations of Bloch modes.

关键词： Nonlinear waves

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44.6 fs pulse generation in an Er:fiber laser at 540 MHz repetition rate

44.6 fs pulse generation in an Er:fiber laser at 540 MHz rep...

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2024 Conference on Lasers and Electro-Optics, CLEO 2024

作者： Chen, Zhendong Yang, Ruoao Tang, Yangpeng Pan, Duo Wang, Ya Cao, Jingpeng Wu, Jian Jun Zhang, Zhigang Chen, Jingbiao State Key Laboratory of Advanced Optical Communication Systems and Networks School of Electronics Peking University Beijing100871 China Zhongshan InitiaLase Technologies Inc. Zhongshan528437 China State Key Laboratory of Information Photonics and Optical Communications Beijing University of Posts and Telecommunications Beijing100876 China

We demonstrate a mode-locked ring-cavity Er:fiber laser at a repetition rate of 540 MHz. The pulse duration is 44.6 fs with a spectral bandwidth of 82 nm. The maximum output power is 280 mW. © Optica Publishing G... 详细信息

ISBN: (纸本)9781957171395

关键词： Fiber lasers

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44.6 fs pulse generation in an Er:fiber laser at 540 MHz repetition rate

44.6 fs pulse generation in an Er:fiber laser at 540 MHz rep...

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CLEO: Science and Innovations in CLEO 2024, CLEO: S and I 2024 - Part of Conference on Lasers and Electro-Optics

关键词： Fiber lasers

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Sound Source Localization Using Phase-sensitive optical Time-domain Reflectometry 13

Sound Source Localization Using Phase-sensitive Optical Time...

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advanced Sensor systems and Applications XIII 2023

作者： Tian, Yu Fan, Xinyu He, Zuyuan State Key Laboratory of Advanced Optical System and Networks Department of Electronic Engineering Shanghai Jiao Tong University 800 Dongchuan Road Shanghai200240 China

ISBN: (纸本)9781510667914

Partial discharge often occurs in power equipment, which erodes insulation and eventually results in insulation failure. As partial discharge will generate sound such as acoustic or ultrasonic waves, a phase-sensitive optical time-domain reflectometry (φ-OTDR) is used to measure these signals. Then the number and locations of sound sources can be calculated using array signal processing methods such as Gerschgorin circle theorem and MUSIC (multiple signal classification) algorithm. In the experiment, several sound sources with frequencies below 600 kHz are used to simulate the partial discharges. Our system shows a high sensitivity and strong noise resistance performance. Accurate number estimation is realized with positioning errors less than 3 cm. © 2023 SPIE.

关键词： Multiple signal classification

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Online Simultaneous Modeling and Gain Profile Optimization for Multi-pump Raman Amplifiers in C+L-band optical systems 49

Online Simultaneous Modeling and Gain Profile Optimization f...

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49th European Conference on optical communications, ECOC 2023

作者： Liu, Xiaomin Zhang, Yihao Liu, Yichen Cai, Meng Yi, Lilin Hu, Weisheng Zhuge, Qunbi State Key Laboratory of Advanced Optical Communication Systems and Networks Department of Electronic Engineering Shanghai Jiao Tong University Shanghai China Peng Cheng Laboratory Shenzhen China

ISBN: (纸本)9781839539954

We propose an online paradigm to simultaneously model and optimize Raman gain profiles. Real-time experiments demonstrate the proposed scheme can approach the optimal modelling and optimization performance within 30 data, reducing ~90% of the data compared with the scheme based on an offline-built model. © The Institution of Engineering & Technology 2023.

关键词： optical systems

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Temperature measurement system for transformer using Brillouin optical correlation domain analysis 13

Temperature measurement system for transformer using Brillou...

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advanced Sensor systems and Applications XIII 2023

作者： Li, Rijing Fan, Xinyu Chang, Yanming Xiao, Zhengyuan He, Zuyuan State Key Laboratory of Advanced Optical System and Networks Department of Electronic Engineering Shanghai Jiao Tong University 800 Dongchuan Road Shanghai200240 China

ISBN: (纸本)9781510667914

Brillouin optical correlation domain analysis (BOCDA) offers high spatial resolution and multi-point measurement capabilities which are ideal for transformer winding temperature measurements. In this article, a BOCDA prototype is developed by changing many equipment to modules, and using field-programmable gate arrays (FPGA) for the control, acquisition, and processing. The system achieves a desired performance with a spatial resolution of 10 cm, a Brillouin frequency shift (BFS) accuracy of about 0.9 MHz, and a measurement speed of 500 points/second. © 2023 SPIE.

关键词： Temperature measurement

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