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Asia communications and Photonics Conference and Exhibition (ACP)

作者： Xi Chen Da Feng Longsheng Li Weisheng Hu State Key Laboratory of Advanced Optical Communication Systems and Networks Shanghai Jiao Tong University Shanghai China Key Laboratory of Hunan Province for New Retail Virtual Reality Technology Hunan University of Technology and Business Changsha China

We propose and experimentally demonstrate a carrier suppressed MDB PAM-4 signal for short-reach IM/DD system without dispersion compensation. The BER result of Volterra-DFE is better than FFE and both can reach the SD... 详细信息

ISBN: (数字)9781943580828

ISBN: (纸本)9781728176567

关键词： Quantization (signal) Equalizers Machine learning optical receivers optical fiber communication Dispersion Photonics

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Frequency-Aware Physics-Inspired Degradation Model for Real-World Image Super-Resolution

arXiv

引用

arXiv 2021年

作者： Dong, Zhenxing Cao, Hong Shen, Wang Gan, Yu Ling, Yuye Zhai, Guangtao Su, Yikai John Hopcroft Center for Computer Science Shanghai Jiao Tong University China Institute of Image Communication and Network Engineering Shanghai Jiao Tong University China Department of Electrical and Computer Engineering University of Alabama TuscaloosaAL35401 United States State Key Lab of Advanced Optical Communication Systems and Networks Shanghai Jiao Tong University China

Current learning-based single image super-resolution (SISR) algorithms underperform on real data due to the deviation in the assumed degradation process from that in the real-world scenario. Conventional degradation processes consider applying blur, noise, and downsampling (typically bicubic downsampling) on high-resolution (HR) images to synthesize low-resolution (LR) counterparts. However, few works on degradation modelling have taken the physical aspects of the optical imaging system into consideration. In this paper, we analyze the imaging system optically and exploit the characteristics of the real-world LR-HR pairs in the spatial frequency domain. We formulate a real-world physics-inspired degradation model by considering both optics and sensor degradation;The physical degradation of an imaging system is modelled as a low-pass filter, whose cut-off frequency is dictated by the object distance, the focal length of the lens, and the pixel size of the image sensor. In particular, we propose to use a convolutional neural network (CNN) to learn the cutoff frequency of real-world degradation process. The learned network is then applied to synthesize LR images from unpaired HR images. The synthetic HR-LR image pairs are later used to train an SISR network. We evaluate the effectiveness and generalization capability of the proposed degradation model on real-world images captured by different imaging systems. Experimental results showcase that the SISR network trained by using our synthetic data performs favorably against the network using the traditional degradation model. Moreover, our results are comparable to that obtained by the same network trained by using real-world LR-HR pairs, which are challenging to obtain in real scenes. © 2021, CC BY.

关键词： Cutoff frequency

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Field Trial of Stable Radio Frequency Transfer system in 100 km Metropolitan optical Fiber Link

Field Trial of Stable Radio Frequency Transfer System in 100...

引用

IEEE International Symposium on Applications of Ferroelectrics (ISAF)

作者： Chenxia Liu Shujin Zhou Zhuoze Zhao Hao Gao Jinting Cong Jianming Shang Xing Chen Bin Luo Song Yu Hong Guo State Key Laboratory of Information Photonics and Optical Communications Beijing University of Posts and Telecommunications Beijing China State Key Laboratory of Advanced Optical Communication Systems and Networks School of Electronics Engineering and Computer Science Center for Quantum Information Technology Center for Computational Science and Engineering Peking University Beijing China

ISBN: (数字)9781728164304

ISBN: (纸本)9781728167534

We report on a stable radio frequency (RF) transfer experiment via 100 km metropolitan optical fiber link in Beijing area. The link connecting Daniufang and Fangzhuang is composed of two parallel 50-km dark optical fibers with a total loss of 31 dB. The dual phase locked loops (dual-PLL) configuration is designed in our stable fiber-optic RF transfer system. The measured fractional frequency stability (ADEV) of 2.4 GHz RF signal transmission system approaches 1.7×10 -14 @1 s and 2.5×10 -17 @10000 s.

关键词： optical attenuators optical fibers Phase locked loops Repeaters Radio frequency optical noise Signal to noise ratio

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Simulation of a nodal-line semimetal in amplitude-shaken optical lattices

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Physical Review A 2020年第2期102卷 023328-023328页

作者： Tanji Zhou Zhongcheng Yu Zhihan Li Xuzong Chen Xiaoji Zhou State Key Laboratory of Advanced Optical Communication Systems and Networks Department of Electronics Peking University Beijing 100871 China School of Physics Peking University Beijing 100871 China Collaborative Innovation Center of Extreme Optics Shanxi University Taiyuan Shanxi 030006 China

As the research of topological semimetals develops, semimetals with nodal-line rings have come into people's vision as a new platform for studying electronic topology. We propose a method that uses ultracold atoms in a two-dimensional amplitude-shaken bipartite hexagonal optical lattice to simulate the nodal-line semimetal, which can be achieved in the experiment by attaching one triangular optical lattice to a hexagonal optical lattice and periodically modulating the intensity and position of the triangular lattice. By adjusting the shaking frequency and well depth difference of the hexagonal optical lattice, a transformation from Dirac semimetal to the nodal-line semimetal is observed in our system. This transformation can be demonstrated by the Berry phase and Berry curvature, which guides the measurement. Furthermore, the amplitude shaking and C3 symmetry generate a time-reversal-symmetry-unstable mode, and the proportion of the mode and the trivial mode of the hexagonal lattice controls the transformation. This proposal paves a way to study nodal-line semimetals in two-dimensional systems, and it contributes to the application of nodal-line semimetals.

关键词： Bose-Einstein condensates Cold gases in optical lattices Honeycomb lattice Bloch-Floquet theorem optical lattices & traps

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From laboratory to Oil Field: The Development of Fiber-optic Microseismic Monitoring system 27

From Laboratory to Oil Field: The Development of Fiber-optic...

引用

27th International Conference on optical Fiber Sensors, OFS 2020

作者： Liu, Fei Pan, Yong Dong, Xiaowei Pan, Shulin Wang, Ningbo He, Xiangge Gu, Lijuan Chen, Zhangyuan Yi, Duo Xie, Bin Zhang, Min Beijing International Center for Gas Hydrate Peking University Beijing100871 China Petro China Xinjiang Oilfield Company Karamay834000 China Southwest Petroleum University Chengdu610500 China State Key Laboratory of Advanced Optical Communication Systems and Networks Peking University Beijing100871 China College of Physics and Optoelectronic Engineering Shenzhen University Shenzhen518061 China

The special fiber-optic microseismic monitoring system has been successfully developed by Peking university and Xinjiang oilfield company. It has performed 7 monitor-ing tasks from 2016 to 2019, providing ideal interp... 详细信息

ISBN: (纸本)9781557523075

关键词： Fiber optics

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LSTM-Based Channel Prediction for Secure Massive MIMO communications Under Imperfect CSI

LSTM-Based Channel Prediction for Secure Massive MIMO Commun...

引用

IEEE International Conference on communications (ICC)

作者： Tenghui Peng Rongqing Zhang Xiang Cheng Liuqing Yang School of Software Engineering Tongji University Shanghai China State Key Laboratory of Advanced Optical Communication Systems and Networks Peking University Beijing China Department of Electrical and Computer Engineering Colorado State University CO USA

ISBN: (数字)9781728150895

ISBN: (纸本)9781728150901

In recent years, massive multiple-input multiple-output (MIMO) has been regarded as a promising technique in the fifth-generation (5G) communication systems. With the ability of focusing transmission beams on users, massive MIMO has a natural advantage in the field of physical layer security to improve the system secrecy performance. However, in practical mobile systems, the imperfect channel state information (CSI) caused by the channel estimation error and the transmission and processing delay will have a non-negligible impact on the system performance. In this paper, we investigate secure communications in a multi-user massive MIMO-enabled vehicular communication networks. Considering the influence of imperfect CSI on the secrecy performance, we derive a tight asymptotic lower bound of the system secrecy capacity under both perfect and imperfect CSI. Moreover, we further analyze the impact of vehicle speed on the system secrecy performance and propose a channel prediction scheme based on (Long Short-Term Memory) LSTM model to compensate for the negative effects of imperfect CSI, which can improve the system secrecy performance in high mobility scenario. Simulation results show that the imperfect CSI severely reduces the system secrecy capacity, but its negative effects can be effectively alleviated through the designed LSTM-based channel prediction and compensation scheme.

关键词： MIMO communication Channel estimation Precoding Interference Network security Physical layer Antennas

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Simulating graphene dynamics in one-dimensional modulated ring array with synthetic dimension

arXiv

引用

arXiv 2021年

作者： Yu, Danying Li, Guangzhen Xiao, Meng Wang, Da-Wei Wan, Yong Yuan, Luqi Chen, Xianfeng State Key Laboratory of Advanced Optical Communication Systems and Networks School of Physics and Astronomy Shanghai Jiao Tong University Shanghai200240 China Key Laboratory of Artificial Micro- and Nano-Structures Ministry of Education School of Physics and Technology Wuhan University Wuhan430072 China Interdisciplinary Center for Quantum Information State Key Laboratory of Modern Optical Instrumentation Zhejiang Province Key Laboratory of Quantum Technology and Device Department of Physics Zhejiang University Hangzhou310027 China National Institute of Metrology Beijing102200 China Shanghai Research Center for Quantum Sciences Shanghai201315 China Jinan Institute of Quantum Technology Jinan250101 China Collaborative Innovation Center of Light Manipulations and Applications Shandong Normal University Jinan250358 China

A dynamically-modulated ring system with frequency as a synthetic dimension has been shown to be a powerful platform to do quantum simulation and explore novel optical phenomena. Here we propose synthetic honeycomb lattice in a one-dimensional ring array under dynamic modulations, with the extra dimension being the frequency of light. Such system is highly re-configurable with modulation. Various physical phenomena associated with graphene including Klein tunneling, valley-dependent edge states, effective magnetic field, as well as valley-dependent Lorentz force can be simulated in this lattice, which exhibits important potentials for manipulating photons in different ways. Our work unveils a new platform for constructing the honeycomb lattice in a synthetic space, which holds complex functionalities and could be important for optical signal processing as well as quantum computing. Copyright © 2021, The Authors. All rights reserved.

关键词： Graphene

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Photon retention in coherently excited nitrogen ions

引用

Science Bulletin 2021年第15期66卷 1511-1517,M0003页

作者： Jinping Yao Luojia Wang Jinming Chen Yuexin Wan Zhihao Zhang Fangbo Zhang Lingling Qiao Shupeng Yu Botao Fu Zengxiu Zhao Chengyin Wu Vladislav VYakovlev Luqi Yuan Xianfeng Chen Ya Cheng State Key Laboratory of High Field Laser Physics and CAS Center for Excellence in Ultra-intense Laser Science Shanghai Institute of Optics and Fine Mechanics(SIOM)Chinese Academy of Sciences(CAS)Shanghai 201800China State Key Laboratory of Advanced Optical Communication Systems and Networks School of Physics and AstronomyShanghai Jiao Tong UniversityShanghai 200240China University of Chinese Academy of Sciences Beijing 100049China School of Physical Science and Technology ShanghaiTech UniversityShanghai 200031China Department of Physics National University of Defense TechnologyChangsha 410073China State Key Laboratory for Mesoscopic Physics School of PhysicsPeking UniversityBeijing 100871China Texas A&M University College StationTX 77843USA Shanghai Research Center for Quantum Sciences Shanghai 201315China Jinan Institute of Quantum Technology Jinan 250101China Collaborative Innovation Center of Light Manipulations and Applications Shandong Normal UniversityJinan 250358China Collaborative Innovation Center of Extreme Optics Shanxi UniversityTaiyuan 030006China

Quantum coherence in quantum optics is an essential part of optical information processing and light *** metal vapors,despite the numerous shortcomings,are traditionally used in quantum optics as a working medium due to convenient near-infrared excitation,strong dipole transitions and long-lived ***,we proposed and experimentally demonstrated photon retention and subsequent re-emittance with the quantum coherence in a system of coherently excited molecular nitrogen ions(N_(2)^(+))which are produced using a strong 800 nm femtosecond laser *** photon retention,facilitated by quantum coherence,keeps releasing directly-unmeasurable coherent photons for tens of picoseconds,but is able to be read out by a time-delayed femtosecond pulse centered at 1580 nm via two-photon resonant absorption,resulting in a strong radiation at 329.3 *** reveal a pivotal role of the excited-state population to transmit such extremely weak re-emitted photons in this *** new finding unveils the nature of the coherent quantum control in N_(2)^(+)for the potential platform for optical information storage in the remote atmosphere,and facilitates further exploration of fundamental interactions in the quantum optical platform with strong-field ionized molecules.

关键词： Quantum coherence Photon retention Coherent quantum control Strong-field ionized molecules

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High Speed Polarization-Division Multiplexing Transmissions Based on the Nonlinear Fourier Transform

引用

ZTE communications 2019年第3期17卷 50-55,62页

作者： WANG Jia ZHAO Yilong HUANG Xin HE Guangqiang State Key Laboratory of Advanced Optical Communication Systems and Networks Electronic Engineering Department Shanghai Jiao Tong University

Polarization-division multiplexing(PDM)with modulation in the nonlinear frequency domain consisting of the discrete and/or continuous spectrum has been recently regarded as a useful method to be utilized in optical fiber communication *** can compensate the optical fiber nonlinearity based on the nonlinear Fourier transform(NFT).In this paper,we combine PDM with the method of nonlinear frequency division multiplexing(NFDM)and demonstrate the achievable transmission rate by increasing the number of multiplexing nonlinear *** the selected subcarriers(i.e.32,64,and 128),the transmission rates are 64 Gbit/s,76.8 Gbit/s,and 109.7 Gbit/s respectively by applying 64-quadrature amplitude modulation(64-QAM)on the nonlinear continuous *** the transmission distance shorter than 1200 km,the transmission rate of 128-NFDM PDM system can even reach up to 153.6 Gbit/s.

关键词： fiber optics communications multiplexing nonlinear optical signal processing

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Reconfigurable Intelligent Surface Assisted High-Speed Train communications: Coverage Performance Analysis and Placement Optimization

arXiv

引用

arXiv 2023年

作者： Liu, Changzhu He, Ruisi Niu, Yong Han, Zhu Ai, Bo Gao, Meilin Ma, Zhangfeng Wang, Gongpu Zhong, Zhangdui The State Key Laboratory of Advanced Rail Autonomous Operation The School of Electronics and Information Engineering The Frontiers Science Center for Smart High-speed Railway System The Beijing Engineering Research Center of High-Speed Railway Broadband Mobile Communications Beijing Jiaotong University Beijing100044 China The State Key Laboratory of Advanced Rail Autonomous Operation Beijing Jiaotong University Beijing100044 China The National Mobile Communications Research Laboratory Southeast University Nanjing211189 China The Department of Electrical and Computer Engineering The University of Houston HoustonTX77004 United States The Department of Computer Science and Engineering Kyung Hee University Seoul446-701 Korea Republic of Henan Joint International Research Laboratory of Intelligent Networking and Data Analysis Zhengzhou University Zhengzhou450001 China Research Center of Networks and Communications Peng Cheng Laboratory Shenzhen China The Tsinghua Space Center the Beijing National Research Center for Information Science and Technology Tsinghua University Beijing100091 China The College of Information Engineering Shaoyang University Shaoyang422000 China The Beijing Key Lab of Transportation Data Analysis and Mining School of Computer and Information Technology Beijing Jiaotong University Beijing100044 China

Reconfigurable intelligent surface (RIS) emerges as maximization problem is formulated to facilitate RIS discrete an efficient and promising technology for the next wireless phase design and RIS placement optimization, which is subject generation networks and has attracted a lot of attention owing to coverage probability constraint. Simulation results validate to the capability of extending wireless coverage by reflecting that better coverage performance and higher travel distance signals toward targeted receivers. In this paper, we consider can be achieved with deployment of RIS. The impacts of some a RIS-assisted high-speed train (HST) communication system key system parameters including transmission power, signal-to-to enhance wireless coverage and improve coverage probability. noise ratio threshold, number of RIS elements, number of RIS First, coverage performance of the downlink single-input-single- quantization bits, horizontal distance between base station and output system is investigated, and the closed-form expression RIS, and speed of HST on system performance are investigated. of coverage probability is derived. Moreover, travel distance In addition, it is found that RIS can well improve coverage probability with limited power consumption for HST communications. Copyright © 2023, The Authors. All rights reserved.

关键词： Railroads

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