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arXiv 2022年

作者： Sun, Shuai Nie, Zhen-Wu Li, Yue-Gang Lin, Hui-Zu Liu, Wei-Tao Chen, Ping-Xing Institute for Quantum Science and Technology College of Science National University of Defense Technology Hunan Changsha410073 China Interdisciplinary Center of Quantum Information College of Science National University of Defense Technology Hunan Changsha410073 China Hunan Key Laboratory of Mechanism and Technology of Quantum Information Hunan Changsha410073 China State Key Laboratory of Advanced Optical Communication Systems and Networks Institute for Quantum Sensing and Information Processing School of Sensing Science and Engineering Shanghai Jiao Tong University Shanghai200240 China

Although optical aperture synthesis has been generally regarded as the only access to very large imager for over a century, the problem of phasing all the giant sub-apertures on the scale of wavelength is still prohibitive. Besides, the accompanied adaptive optics combatting the atmospheric turbulence is also bulky and complicated. We here propose a new paradigm aperture synthesis imager through turbulence, based on computational ghost imaging method. The complex aberrations on the signal path are computationally cancelled by introducing an optimum compensation phase on the reference path. With the advanced aberration cancellation, our imager is free from phasing and aberrations problem. The image degradation due to turbulence is also suppressed and even eliminated without any guide star or wavefront shaping device. Experimentally, diffraction-limited imaging is achieved under turbulence featuring transverse coherence length far less than the optical aperture of the system. Copyright © 2022, The Authors. All rights reserved.

关键词： Atmospheric turbulence

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Synergetic Learning of Heterogeneous Temporal Sequences for Multi-Horizon Probabilistic Forecasting

arXiv

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arXiv 2021年

作者： Li, Longyuan Zhang, Jihai Yan, Junchi Jin, Yaohui Zhang, Yunhao Duan, Yanjie Tian, Guangjian MoE Key Lab of Artificial Intelligence AI Institute Shanghai Jiao Tong University China State Key Lab of Advanced Optical Communication System and Network Shanghai Jiao Tong University China Department of Computer Science and Engineering Shanghai Jiao Tong University China Huawei Noah’s Ark Lab China

Time-series is ubiquitous across applications, such as transportation, finance and healthcare. Time-series is often influenced by external factors, especially in the form of asynchronous events, making forecasting difficult. However, existing models are mainly designated for either synchronous time-series or asynchronous event sequence, and can hardly provide a synthetic way to capture the relation between them. We propose Variational Synergetic Multi-Horizon Network (VSMHN), a novel deep conditional generative model. To learn complex correlations across heterogeneous sequences, a tailored encoder is devised to combine the advances in deep point processes models and variational recurrent neural networks. In addition, an aligned time coding and an auxiliary transition scheme are carefully devised for batched training on unaligned sequences. Our model can be trained effectively using stochastic variational inference and generates probabilistic predictions with Monte-Carlo simulation. Furthermore, our model produces accurate, sharp and more realistic probabilistic forecasts. We also show that modeling asynchronous event sequences is crucial for multi-horizon time-series forecasting. © 2021, CC BY.

关键词： Time series

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Sampling timing jitter in dispersion-managed frequency microcombs via a fiber interferometer

Sampling timing jitter in dispersion-managed frequency micro...

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Conference on Lasers and Electro-Optics (CLEO)

作者： Wenting Wang Hao Liu Tristan Melton Jinghui Yang Abhinav Kumar Vinod Jinkang Lim Yoon-Soo Jang Heng Zhou Mingbin Yu Dim-Lee Kwong Peter DeVore Jason Chou Chee Wei Wong Fang Lu Mesoscopic Optics and Quantum Electronics Laboratory University of California Los Angeles CA United States of America Key Lab of Optical Fiber Sensing and Communication Networks University of Electronic Science and Technology of China Chengdu China Institute of Microelectronics A*STAR Singapore Singapore State Key Laboratory of Functional Materials for Informatics Shanghai Institute of Microsystem and Information Technology and Shanghai Industrial Technology Research Institute Shanghai China Lawrence Livermore National Laboratory Livermore CA United States of America

We characterized timing jitter of dispersion-managed frequency microcomb with femtosecond timing resolution through fiber interferometry for the first time. The measured timing jitter PSD and integrated timing jitter ... 详细信息

ISBN: (数字)9781957171050

ISBN: (纸本)9781665466660

关键词： Timing jitter Time-frequency analysis Fluctuations Measurement by laser beam optical variables measurement Timing Ultrafast optics

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Free-Electron-Driven Orbital Angular Momentum Emitter

Free-Electron-Driven Orbital Angular Momentum Emitter

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UK, Europe, China Millimeter Waves and THz Technology Workshop (UCMMT)

作者： Juan-Feng Zhu Chao-Hai Du Zi-Wen Zhang Fan-Hong Li Pu-Kun Liu Adrian W. Cross Liang Zhang State Key Laboratory of Advanced Optical Communication Systems and Networks Peking University Beijing China SUPA University of Strathclyde Glasgow Scotland UK

ISBN: (数字)9781728190648

ISBN: (纸本)9781728190655

A free-electron-driven orbital angular momentum (OAM) emitter is introduced in this paper. When the free electron passes over the cylindrical grating, the spoof surface plasmon (SSP) is stimulated in this system. With loading a helical wire which induces a gradient azimuthal phase distribution the system, the SSP mode will be converted into the spatial OAM radiation. The operating frequency of the OAM mode can be tuned by the electron beam energy of the surface plasmon. Compared with the Smith-Purcell radiation from the helical grating, the field intensity is enhanced by about 50 times. This method provides an efficient way to generate the OAM mode, and may find applications in a communication system.

关键词： Gratings Wires Dispersion Orbits Physics optical fiber communication Surface emitting lasers

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Structural phase transition of monochalcogenides investigated with machine learning

引用

Physical Review B 2022年第9期105卷 094116-094116页

作者： J. Zhang F. Zhang D. Wei L. Liu X. Liu D. Fang G. X. Zhang X. Chen D. Wang School of Microelectronics & State Key Laboratory for Mechanical Behavior of Materials Xi'an Jiaotong University Xi'an 710049 China Key Lab of Micro-Nano Electronics and System Integration of Xi'an City Xi'an Jiaotong University Xi'an 710049 China Guangxi Key Laboratory of Optical and Electronic Materials and Devices College of Materials Science and Engineering Guilin University of Technology Guilin 541004 China Engineering Research Center of Nanoelectronic Integration and Advanced Equipment Ministry of Education School of Physics and Electronic Science East China Normal University Shanghai 200062 China MOE Key Laboratory for Nonequilibrium Synthesis and Modulation of Condensed Matter School of Physics Xi' an Jiaotong University Xi'an 710049 China School of Chemistry and Chemical Engineering Harbin Institute of Technology Harbin 150001 China Department of Applied Physics Aalto University Espoo 00076 Finland

As machine learning becomes increasingly important in science and engineering, it holds the promise to provide a universal approach applicable to various systems to investigate their crystalline phase transitions. Here, we build and train accurate artificial neural networks that can distinguish tiny energy difference, which is crucial to predict the crystalline phase transitions. Employing the trained artificial neural networks in Monte Carlo simulations as the surrogate energy function, we apply this approach to monochalcogenides, including bulk and two-dimensional monolayer SnTe and GeTe, investigating their crystalline phase transitions. The machine-learning approach, when viewed as providing a universal mathematical structure, can be transferred to the investigation of other materials when the training data set generated with ab initio methods are available. Moreover, the machine-learning approach resolves the difficulties associated with constructing the effective Hamiltonian for monochalcogenides, showing great potential with its accuracy and efficiency.

关键词： Ferroelectricity Structural phase transition Chalcogenides Machine learning

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Bidirectional dark soliton mode-locked fiber laser based on thulium-doped fiber saturable absorber

Bidirectional dark soliton mode-locked fiber laser based on ...

引用

Laser Science and Technology, LST_2019

作者： Zhang, Wenyan Zhan, Li Xian, Tianhao Gao, Lirun State Key Lab of Advanced Optical Communication Systems and Networks Department of Physics and Astronomy Shanghai Jiao Tong University Shanghai200240 China

A bidirectional dark-soliton fiber laser is demonstrated for the first time. The experimental results of the output counter-propagating pulses and its potential applications for rotation sensing are discussed. © ... 详细信息

ISBN: (纸本)9781943580729

关键词： Fiber lasers

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Slope-Assisted Brillouin-Based Distributed Fiber-Optic Sensing Techniques

Advanced Devices and Instrumentation

引用

advanced Devices and Instrumentation 2021年 2021卷

作者： Fan, Xinyu Wang, Bin Yang, Guangyao He, Zuyuan State Key Laboratory of Advanced Optical Communication Systems and Networks Department of Electronic Engineering Shanghai Jiao Tong University Shanghai200240 China Radar Research Lab School of Information and Electronics Beijing Institute of Technology Beijing100081 China Key Laboratory of Electronic and Information Technology in Satellite Navigation Beijing Institute of Technology Ministry of Education Beijing100081 China Beijing Institute of Technology Chongqing Innovation Center Chongqing401120 China

Brillouin-based fiber-optic sensing has been regarded as a powerful distributed measurement tool for monitoring the conditions of modern large civil and geotechnical structures, since it provides continuous environmental information (e.g., temperature and strain) along the whole fiber used for sensing applications. In the past few decades, great research efforts were devoted to improve its performance in terms of measurement range, spatial resolution, measurement speed, sensitivity, and costeffectiveness, of which the slope-assisted measurement scheme, achieved by exploiting the linear slope of the Brillouin gain spectrum (BGS), have paved the way for dynamic distributed fiber-optic sensing. In this article, slope-assisted Brillouin-based distributed fiber-optic sensing techniques demonstrated in the past few years will be reviewed, including the slope-assisted Brillouin optical time-domain analysis/reflectometry (SA-BOTDA/SA-BOTDR), the slope-assisted Brillouin dynamic grating (BDG) sensor, and the slope-assisted Brillouin optical correlation domain analysis/reflectometry (SA-BOCDA/SA-BOCDR). Avenues for future research and development of slope-assisted Brillouin-based fiber-optic sensors are also prospected. © 2021 Xinyu Fan et al.

关键词： Fiber optic sensors

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On-Chip Mode-Division Multiplexing with Modal Crosstalk Mitigation

On-Chip Mode-Division Multiplexing with Modal Crosstalk Miti...

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optical Fiber communication (OFC) Conference

作者： Yetian Huang Ruihuan Zhang Haoshuo Chen Hanzi Huang Qingming Zhu Yu He Yuan Yuan Yingxiong Song Nicolas K. Fontaine Roland Ryf Yong Zhang Yikai Su Min Wang Key Laboratory of Specialty Fiber Optics and Optical Access Networks Joint International Research Laboratory of Specialty Fiber Optics and Advanced Communication Shanghai Institute for Advanced Communication and Data Science Shanghai University Shanghai China State Key Lab of Advanced Optical Communication Systems and Networks Shanghai Jiao Tong University Shanghai China Nokia Bell Labs Holmdel NJ USA

We experimentally demonstrate modal crosstalk mitigation over an on-chip mode-division multiplexing link employing low-coherence matched detection. 20-Gbaud QPSK and 8-PSK mode-multiplexed signals are successfully tra... 详细信息

ISBN: (数字)9781943580712

ISBN: (纸本)9781728167626

关键词： Modal crosstalk Mode division multiplexing optical directional couplers Phase recovery Signal processing Signal recovery

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All-optical single-species cesium atomic comagnetometer with optical free induction decay detection

arXiv

引用

arXiv 2020年

作者： Yang, Yucheng Wu, Teng Chen, Jingbiao Peng, Xiang Guo, Hong State Key Laboratory of Advanced Optical Communication Systems and Networks Department of Electronics Center for Quantum Information Technology Peking University Beijing100871 China

Atomic comagnetometers, which measure the spin precession frequencies of overlapped species simultaneously, are widely applied to search for exotic spin-dependent interactions. Here we propose and implement an all-optical single-species Cs atomic comagnetometer based on the optical free induction decay (FID) signal of Cs atoms in hyperfine levels Fg = 3 & 4 within the same atomic ensemble. We experimentally show that systematic errors induced by magnetic field gradients and laser fields are highly suppressed in the comagnetometer, but those induced by asynchronous optical pumping and drift of residual magnetic field in the shield dominate the uncertainty of the comagnetometer. With this comagnetometer system, we set the constraint on the strength of spin-gravity coupling of the proton at a level of 10−18 eV, comparable to the most stringent one. With further optimization in magnetic field stabilization and spin polarization, the systematic errors can be effectively suppressed, and signal-to-noise ratio (SNR) can be improved, promising to set more stringent constraints on spin-gravity interactions. Copyright © 2020, The Authors. All rights reserved.

关键词： optical pumping

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A Two-step Parameter Estimation Algorithm for Microwave Photonic Spectrum Awareness

A Two-step Parameter Estimation Algorithm for Microwave Phot...

引用

2019 IEEE International Conference on Signal, Information and Data Processing, ICSIDP 2019

作者： Chen, Lu Gao, Yesheng Liu, Xingzhao Wang, Zhicheng State Key Laboratory of Advanced Optical Communication System and Networks Shanghai Jiao Tong University Department of Electronic Engineering Shanghai China Shanghai Radio Equipment Research Institute Shanghai China

ISBN: (纸本)9781728123455

Parameter estimation of wideband linear frequency modulation (LFM or chirp) signals is of significant importance in a wide range of areas such as radar, sonar and communications. However, estimation methods based on digital signal processing are limited by the calculation load. Thanks to the intrinsic advantages of large bandwidth, low transmission loss and immunity to electromagnetic interference of modern photonics, microwave photonic techniques are attractive for processing wideband signals. In this paper, a parameter estimation algorithm for the output signal of the photonics-based system is proposed. The algorithm consists of two steps. In the first stage, modified chirp Fourier transform is applied to estimate the parameters roughly. In the second stage, linear fitting and Rife algorithm are performed on the basis of the first step to obtain more accurate results. The simulation results demonstrate the efficacy of the proposed algorithm. © 2019 IEEE.

关键词： Chirp modulation

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