检索结果-南通市图书馆

free-space optical communication using patterned modulation and bucket detection

在线全文

学校读者我要写书评

暂无评论

Chinese Optics Letters 2016年第11期14卷 38-42页

作者：冒添逸陈钱何伟基邹云浩戴慧东顾国华 Jiangsu Key Laboratory of Spectral Imaging & Intelligence Sense(SⅡS) Nanjing University of Science and Technology Key Laboratory of Intelligent Perception and Systems for High-Dimensional Information of Ministry of Education Nanjing University of Science and Technology

In this Letter,free-space optical（FSO） communication using patterned modulation and bucket detection is introduced to improve the bit error rate（BER）performance in complex and noisy *** scattered light is averaged in this communication ***-order correlation,wavelet normalization,and compressed sensing are combined in the reconstruction algorithm.A signal with.V bits is reconstructed well from much less than N *** simulations and experiments are performed without the narrowband optical filters used in traditional FSO *** can also be employed in real networks where secure communication is *** provides the great opportunity to pave the way for real applications of FSO communication.

关键词： optical communications free-space optical communication

Online search for UAV relay placement for free-space optical communication under shadowing

在线全文

学校读者我要写书评

暂无评论

Intelligent and Converged Networks 2023年第1期4卷 28-40页

作者： Yuanshuai Zheng Yinjun Wang Junting Chen School of Science and Engineering and the Future Network of Intelligence Institute(FNii) The Chinese University of Hong KongShenzhen 518172China

Unmanned aerial vehicle(UAV)relaying is promising to overcome the challenge of signal blockage in free-space optical(FSO)communications for users in dense urban *** works on UAV relay placement are mostly based on simplified line-of-sight(LOS)channel models or probabilistic channel models,and thus fail to capture the actual LOS status of the optical communication *** contrast,this paper studies three-dimensional(3D)online placement for a UAV to construct relay links to two ground users in deep shadow with LOS *** analyzing the properties of the UAV relay placement problem,it is found that searching on a plane that approximates the equipotential surface can achieve a good performance and complexity trade-off for a good placement of the UAV relay in *** on these insights,a two-stage online search algorithm on an equipotential plane(TOSEP)is developed for a special case where the equipotential surface turns out to be an equipotential *** the general case,a strategy called gradient projected online search algorithm on an approximated equipotential plane(GOSAEP)is developed,which approximates the equipotential surface with a perpendicular plane using the gradient projection *** experiments are conducted over a real-world city topology,and it is shown that the GOSAEP achieves over 95%of the performance of the exhaustive 3D search scheme within a 300-m search length.

关键词： free-space optical communication relay communication unmanned aerial vehicle(UAV) trajectory design capacity maximization

Performance of free-space optical communication systems using circle polarization shift keying with spatial diversity receivers

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Chinese Optics Letters 2013年第14期11卷 1-4页

作者：刘超姚勇杨彦甫袁易君赵宇峰于本双 Department of Electronic and Information Engineering Shenzhen Graduate School Harbin Institute of Technology Shenzhen 518055 China

A closed-form bit-error rate （BER） expression is derived for free-space optical （FSO） communication systems with circle polarization shift keying and spatial diversity receivers in the gamma-gamma （GG） distribution fading channel. This model can predict the performance without the need of lengthy simulation runs. The performance can be analyzed by some system parameters such as atmospheric conditions, link length, communication wavelength, receiver aperture size, and number of spatial diversity receivers. Numerical results demonstrate the influence of the above parameters on the FSO systems and show quantitatively the differences in behavior among various different parameters.

关键词： 010.1300 Atmospheric propagation 010.1330 Atmospheric turbulence 060.2605 free-space optical communication 060.4080 Modulation

High-speed free-space optical communication using standard fiber communication components without optical amplification

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Advanced Photonics Nexus 2023年第6期2卷 1-6页

作者： Hua-Ying Liu Yao Zhang Xiaoyi Liu Luyi Sun Pengfei Fan Xiaohui Tian Dong Pan Mo Yuan Zhijun Yin Guilu Long Shi-Ning Zhu Zhenda Xie Nanjing University College of Engineering and Applied Sciencesand Collaborative Innovation Center of Advanced MicrostructuresSchool of Electronic Science and EngineeringSchool of PhysicsNational Laboratory of Solid State MicrostructuresNanjingChina Beijing Academy of Quantum Information Sciences BeijingChina Xin Lian Technology Co. Ltd.HuzhouChina

free-space optical communication(FSO)can achieve fast,secure,and license-free communication without physical cables,providing a cost-effective,energy-efficient,and flexible solution when fiber connection is *** achieve FSO on demand,portable FSO devices are essential for flexible and fast deployment,where the key is achieving compact structure and plug-and-play ***,we develop a miniaturized FSO system and realize 9.16 Gbps FSO in a 1 km link,using commercial single-mode-fibercoupled optical transceiver modules without optical *** automatic four-stage acquisition,pointing,and tracking systems are developed,which control the tracking error within 3μrad,resulting in an average link loss of 13.7 *** is the key for removing optical amplification;hence FSO is achieved with direct use of commercial transceiver modules in a bidirectional *** FSO device is within an overall size of 45 cm×40 cm×35 cm,and 9.5 kg weight,with power consumption of∼10 *** optical link up to 4 km is tested with average loss of 18 dB,limited by the foggy test *** better weather conditions and optical amplification,longer FSO can be *** a portable and automatic FSO system will produce massive applications of field-deployable high-speed wireless communication in the future.

关键词： free-space optical communication acquisition,pointing,and tracking system field-deployable system

High-accuracy mode recognition method in orbital angular momentum optical communication system

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Chinese Optics Letters 2022年第2期20卷 5-11页

作者： Lin Zhao Yuan Hao Li Chen Wenyi Liu Meng Jin Yi Wu Jiamin Tao Kaiqian Jie Hongzhan Liu Guangdong Provincial Key Laboratory of Nanophotonic Functional Materials and Devices Guangzhou 510006China School of Electronics and Information Technology Sun Yat-sen UniversityGuangzhou 510275China

Vortex optical communication has been a hot research field in recent years. A key step is mode recognition in the orbital angular momentum(OAM) free-space optical(FSO) communication system. In this article, we propose an OAM mode recognition method based on image recognition technology, which uses the interferogram between the vortex beam and the Gaussian beam to identify the OAM mode. In order to resist the influence of atmospheric turbulence on the recognition accuracy, we added a Gaussian smoothing filter into the recognition process. Moreover, we used random phase screens to generate interferogram sets at distances of 1 km and 2 km. The verification result shows that the proposed scheme produces high identification accuracy for the distorted optical field. The average accuracy can reach 100% and 87.78% under the conditions of medium-and strong-turbulence levels, respectively. It is anticipated that these results might be helpful for improving the reliability of the OAM-FSO communication system in the future.

关键词： orbital angular momentum mode identification free-space optical communication atmospheric turbulence

Experimental demonstration of single-mode fiber coupling using adaptive fiber coupler

在线全文

学校读者我要写书评

暂无评论

Chinese Physics B 2014年第1期23卷 260-265页

作者：罗文耿超武云云谭毅罗奇刘红梅李新阳 Key Laboratory on Adaptive Optics Chinese Academy of Sciences Chengdu 610209 China Institute of Optics and Electronics Chinese Academy of Sciences Chengdu 610209 China University of Chinese Academy of Sciences Beijing 100049 China

Coupling plane wave into a single-mode fiber （SMF） with high and steady coupling efficiency is crucial for fiber- based free-space laser systems, where random angular jitters are the main influencing factors of fiber coupling. In this paper, we verified a new adaptive-optic device named adaptive fiber coupler （AFC） which could compensate angular jitters and improve the SMF coupling efficiency in some degree. Experiments of SMF coupling under the angular jitter situation using AFC have been achieved. Stochastic parallel gradient descent （SPGD） algorithm is employed as the control strategy, of which the iteration rate is 625 Hz. In closed loop, the coupling efficiency keeps above 65% when angular errors are below 80/3tad. The compensation bandwidth is 35 Hz at sine-jitter of 15 ~rad amplitude with average coupling efficiency of above 60%. Also, experiments with simulated turbulence have been studied. The average coupling efficiency increases from 31.97% in open loop to 61.33% in closed loop, and mean square error （MSE） of coupling efficiency drops from 7.43% to 1.75%.

关键词： single-mode fiber coupling adaptive fiber coupler adaptive optics free-space optical communication

Geometrically Shaped 32QAM and Modified Binary Switching Coding Method in Underwater Visible Light communication

在线全文

学校读者我要写书评

暂无评论

Chinese Journal of Electronics 2022年第6期31卷 1106-1111页

作者： SHI Jianyang CAI Jifan QIN Guojin JIN Ruizhe LIN Xianhao CHI Nan Key Laboratory for Information Science of Electromagnetic Waves (MoE) Fudan University Peng Cheng Laboratory Shanghai Engineering Research Center of Low-Earth-Orbit Satellite communication and Applications Shanghai Collaborative Innovation Center of Low-Earth-Orbit Satellite communication Technology

Visible light communication(VLC) has emerged as a promising communication method in 6G,particularly in the domain of underwater ***, because of its intimate coupling to the lightemitting diodes(LED), the transmission rate is limited by the modulation bandwidth and the nonlinearity of the LED. With current device development, LED bandwidth is substantially lower than that of other optical communication devices, necessitating improved spectral efficiency and nonlinearity robustness to achieve high-speed transmission. In this paper, we propose a hexagonal constellation-based geometrically shaped(GS) 32QAM with carrierless amplitude and phase(CAP) modulation for the underwater VLC system. A comprehensive performance comparison of four GS modulation methods, including our proposed hexagonal-32QAM, normal 32QAM, square-32QAM and 32APSK is investigated in both theory and experiment. The hexagonal-32QAM with a modified binary switching coding(BSC) can obtain a Q factor gain of 0.44 dB, and a data rate improvement of 25 Mb/s compared with Gary coding based normal 32QAM. The experimentally results illustrate the feasibility of geometric shaping 32QAM in underwater visible light communication.

关键词： underwater VLC system comprehensive performance comparison modulation bandwidth amplitude shift keying carrierless amplitude and phase modulation light emitting diodes improved spectral efficiency Q factor gain communication method LED nonlinearity square-32QAM underwater visible light communication data rate improvement binary codes high-speed transmission light-emitting diodes hexagonal constellation-based geometrically shaped 32QAM quadrature amplitude modulation Gary coding based normal 32QAM free-space optical communication optical communication devices underwater optical wireless communication device development LED bandwidth optical modulation underwater communication geometric shaping 32QAM nonlinearity robustness GS modulation methods modified binary switching coding method BSC CAP phase modulation phase shift keying 32APSK hexagonal-32QAM

Mode Purity Improvement of High-Order Vortex Waves

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Chinese Journal of Electronics 2022年第6期31卷 1146-1154页

作者： LIN Jie YANG Guang LI Weiwen AN Cheng Department of Electronic Engineering Xiamen University

Vortex electromagnetic waves can carry orbital angular momentum(OAM) modes of different order number, which are mutually orthogonal. communication technologies multiplexing different OAM topological charges have attracted extensive attention in improving spectrum utilization. In this regard, the efficient generation of OAM modes becomes a key issue. However, it is difficult to generate high-order OAM modes by using a microstrip antenna with a simple structure, and the mode purity is usually not high. Methodologically, the OAM wave of a microstrip antenna is mostly achieved by synthesizing degenerate eigenmodes. In this paper, combined with eigenmode analysis, the construction of high-order and high-purity OAM mode microstrip antennas is carried out from the perspectives of radiating element,ground plane, and structural symmetry. For a regular hexagonal patch antenna of the 4th-order OAM mode,the mode purity is improved from about 40% to over 80%by removing the inner conductor of the patch layer, using a circular ground plane, and adding lug patches on the outside. This method of improving mode purity through the analysis of mode significance and characteristic current distribution also has guiding significance for the design of other high-order OAM mode patch antennas.

关键词： mode purity improvement regular hexagonal patch antenna vortex electromagnetic waves orbital angular momentum modes microstrip antennas angular momentum antenna radiation patterns microstrip antenna different order number OAM wave current distribution free-space optical communication high-order OAM modes 4th-order OAM mode multiplexing mode significance high-order vortex different OAM topological charges high-order OAM mode patch antennas

A Waveguide Gate-Type Complex Detecting Mechanism on Micro-Channel Plate Substrate

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Chinese Journal of Electronics 2019年第3期28卷 625-629页

作者： MU Yining FAN Haibo LIU Chunyang LIU Guozhen School of Science Changchun University of Science and Technology

The waveguide gate-type mechanism on micro-channel plate substrate was firstly put forward for the complex photo detection in free space optical communication(FSO). Based on the losses of energy coupling between both Micro-channel plates(MCP), we further proposed waveguide gate-type complex detecting mechanism, which was verified in electron optic system by vacuum testing. With the application of the complex detecting mechanism, the device performance has greatly improved, including higher space optical transfer and wider dynamic detecting range.

关键词： Detectors Guided waves free-space optical communication