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Theoretical and numerical analyses for PDM-IM signals using stokes vector receivers

Science China(Information Sciences) 2020年第10期63卷 194-202页

作者： Jiahao HUO Xian ZHOU Chao SHANG Wei HUANGFU Jinhui YUAN Huansheng NING Keping LONG Changyuan YU Alan Pak Tao LAU Chao LU Beijing Engineering and Technology Research Center for Convergence Networks and Ubiquitous Services University of Science and Technology Beijing Department of Electronic and Information Engineering The Hong Kong Polytechnic University Key Laboratory of Luminescence and Optical Information Ministry of EducationInstitute of Optical InformationSchool of ScienceBeijing Jiaotong University Department of Electrical Engineering The Hong Kong Polytechnic University

Different from current coherent-detection-based long-haul transmission systems, inter-and intradatacenter transmissions require a simpler transmitter and receiver. A promising way to significantly meet the demands of datacenter transmission is polarization division multiplexing intensity modulation with direct detection(PDM-IM-DD) using a stokes vector receiver(SVR). However, for different SVR architectures,the corresponding demultiplexing matrix is required to recover the stokes vectors from the detected signals,which are combined with an arbitrary state of polarization(SOP), will change the effect of noise dynamically and significantly influence the system performance. In this study, PDM-IM signals using four SVRs,i.e., a 90? optical hybrid with 2 balanced photodetectors(BPDs) and 2 photodetectors(PDs), a 90? optical hybrid with 4 PDs, a stokes analyzer and a 3×3 coupler with 4 PDs, are studied theoretically and numerically. Theoretical system models using the four SVRs are developed, and the noise power variations are analyzed quantitatively based on these models. Moreover, the performance of the systems is also investigated for 224 Gbit/s polarization division multiplexing pulse amplitude modulation 4 level with direct detection(PDM-PAM4-DD) transmission in a simulation. The simulation results show that the bit error rate(BER)performance of the systems is consistent with the theoretical noise power variation curves. The theoretical analysis scheme is helpful for the practical design of SVR-based systems.

关键词： short-reach optical communications PAM4 polarization division multiplexing stokes vector direct detection

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Forward modelling of the Cotton-Mouton effect polarimetry on EAST tokamak

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Plasma Science and Technology 2024年第3期26卷 100-117页

作者：沈敏勇张际波张耀揭银先刘海庆谢锦林丁卫星 School of Nuclear Science and Technology University of Science and Technology of ChinaHefei 230026People's Republic of China Institute of Plasma Physics Chinese Academy of SciencesHefei 230031People's Republic of China

Measurement of plasma electron density by far-infrared laser polarimetry has become a routine and indispensable tool in magnetic confinement fusion *** article presents the design of a Cotton-Mouton polarimeter interferometer,which provides a reliable density measurement without fringe ***-Mouton effect on Experimental Advanced Superconducting Tokamak(EAST)is studied by stokes equation with three parameters(s_(1),s_(2),s_(3)).It demonstrates that under the condition of a small Cotton-Mouton effect,parameter s_(2)contains information about Cotton-Mouton effect which is proportional to the line-integrated *** a typical EAST plasma,the magnitude of Cotton-Mouton effects is less than 2πfor laser wavelength of 432μ*** effect due to density gradient is calculated to be *** modulation of stokes parameters(s_(2),s_(3))provides heterodyne *** to the instabilities arising from laser oscillation and beam refraction in plasmas,it is necessary for the system to be insensitive to variations in the amplitude of the detection ***,it is shown that non-equal amplitude of X-mode and O-mode within a certain range only affects the DC offset of stokes parameters(s_(2),s_(3))but does not greatly influence the phase measurements of Cotton-Mouton effects.

关键词： EAST Cotton-Mouton effect polarimeter interferometer electron density measurement stokes vector

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vector Radiative Transfer in a Vertically Inhomogeneous Scattering and Emitting ***Ⅰ:A New Discrete Ordinate Method

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Journal of Meteorological Research 2024年第2期38卷 209-224页

作者： Ziqiang ZHU Fuzhong WENG Yang HAN Chinese Academy of Meteorological Sciences China Meteorological AdministrationBeijing 100081 University of Chinese Academy of Sciences Beijing 100049 CMA Earth System Modeling and Prediction Centre China Meteorological Administration(CMA)Beijing 100081 State Key Laboratory of Severe Weather Chinese Academy of Meteorological SciencesChina Meteorological AdministrationBeijing 100081

The original vector discrete ordinate radiative transfer(VDISORT)model takes into account stokes radiance vector but derives its solution assuming azimuthal symmetric surface reflective matrix and atmospheric scattering phase matrix,such as the phase matrix derived from spherical particles or randomly oriented non-spherical *** this study,a new VDISORT is developed for general atmospheric scattering and boundary *** vector is decomposed into both sinusoidal and cosinusoidal harmonic modes,and the radiance at arbitrary viewing geometry is solved directly by adding two zero-weighted points in the Gaussian quadrature *** complex eigenvalues in homogeneous solutions are also taken into full *** accuracy of VDISORT model is comprehensively validated by four cases:Rayleigh scattering case,the spherical particle scattering case with the Legendre expansion coefficients of 0th-13th orders of the phase matrix(hereinafter L13),L13 with a polarized source,and the randomoriented oblate particle scattering case with the Legendre expansion coefficients of 0th-11th orders of the phase matrix(hereinafter L11).In all cases,the simulated radiances agree well with the benchmarks,with absolute biases less than 0.0065,0.0006,and 0.0008 for Rayleigh,unpolarized L13,and L11,*** a polarized bidirectional reflection distribution function(pBRDF)matrix is used as the lower boundary condition,VDISORT is now able to handle fully coupled atmospheric and surface polarimetric radiative transfer processes.

关键词： radiative transfer discrete ordinate polarization stokes vector vector discrete ordinate radiative transfer(VDISORT)

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Restoring Polarization Angle Map for High- Fidelity Underwater Imaging

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Journal of Beijing Institute of Technology 2022年第2期31卷 178-184页

作者： Yiming Li Liheng Bian Yangtze Delta Re-gion Academy of Beijing Institute of Technology(Jiaxing) Jiaxing 314019China School of Information and Electronics Beijing Institute of TechnologyBeijing 100081China.

Obtaining polarization information enables researchers to enhance underwater imaging quality by removing backscattering effect and to distinguish targets of different ***,due to the simplified assumption of unpolarized target light,most of the existing underwater polari-metric methods lose part of the polarization information,resulting in degraded imaging *** this work,a novel underwater polarimetric method is reported,which obtains the angle of polariza-tion(AOP)map to improve imaging ***,the stokes vectors were exploited to re-move the backscattering effect by obtaining two pairs of orthogonal polarization sub-images of the underwater *** target reflected light and the angle between the polarization directions of the target reflected light and the backscattered light were computed through the two groups of the or-thogonal polarized *** AOP map of the target light could be derived from the stokes ***,the transmission map of the target light was estimated by using the non-local color priorly combined with the properties of light propagating *** show that the reported technique enables distinguishing different targets when the colors are *** quantit-ative metrics validate that the reported technique produces state-of-the-art performance for under-water imaging.

关键词： underwater imaging polarization angle of polarization(AOP) stokes vector

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Model-based target decomposition with the π/4 mode compact polarimetry data

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Science China(Information Sciences) 2016年第6期59卷 189-198页

作者： Shenglong GUO Yang LI Wen HONG Jianfeng WANG Xiaoyang GUO Institute of Electronics Chinese Academy of Sciences School of Electronics Electrical and Communication EngineeringUniversity of Chinese Academy of Sciences

In this paper, model-based(surface, dihedral and volume scattering) target decomposition technique is proposed to decompose the π/4 mode compact polarimetric radar data. A general relationship between fully polarimetric coherence matrix and the stokes vector of the π/4 mode compact polarimetric data is first established. Based on the stokes vector, a proposed algorithm to retrieve the power of three scattering mechanisms is given in details. We validate this algorithm with L-band AIRSAR, San Francisco Bay, and results of decomposition are discussed and assessed in detail by being compared with the quad-pol Freeman-Durden decomposition results. Finally, the π/4 mode decomposition is compared with the CTLR(circular transmitting and linear reeving) mode, and with the π/4 mode m- δ targets decomposition. The comparison results are analyzed and discussed in detail.

关键词： π/4 mode compact polarimetry mode-based target decomposition stokes vector RVo G model radar polarimetry

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Instantaneous polarization statistics of electromagnetic waves

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Science in China(Series F) 2004年第5期47卷 623-634页

作者： WANGXuesong LIYongzhen DAIDahai XIAOShunping ZHUANGZhaowen SchoolofElectronicScienceandEngineering NationalUniversityofDefenseTechnologyChangsha410073China

The problem of statistical description of instantaneous polarization of electromagnetic waves is studied. First, the physical meanings of instantaneous stokes vectors’ components are analyzed, which provide a short cut for solving statistical distribution functions of instantaneous stokes vectors. Second, in the condition of Gaussian hypothesis, the analytical expressions of probability density function (PDF) of instantaneous stokes vectors are presented. Finally, some computation results are presented in the condition of two independent polarization channels, which show the validity and simplicity of the statistical description method.

关键词： instantaneous polarization stokes vector statistical analysis.

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An analytical model for the polarization of synchrotronradiation in a soft X-ray region

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Chinese Physics C 2013年第3期37卷 113-117页

作者：席识博崔明启朱京涛杨栋亮徐伟刘利娟郭志英赵佳 Institute of High Energy Physics Chinese Academy of Sciences Institute of Precision Optical Engineering Physics DepartmentTongji University Beijing University of Technology and Business

Conventionally, the polarization of a synchrotron soft X-ray beam is measured through a polarimeter based on multilayer optical elements. The major drawback of the traditional approach is the difficulty in comparing different configurations due to the misalignment of each incident angle. In this paper, a new analytical model, based on the variation of reflectivity for different incident angles, is established to facilitate the extraction of important polarization-related information, i.e. angular distribution of polarization components, a tiny change of the direction of azimuth rotation axis of polarizer, etc.

关键词： soft X-ray polarization multilayer polarizer stokes vector

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Statistical characteristics of the normalized stokes parameters

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Science in China(Series F) 2008年第10期51卷 1594-1606页

作者： LIU Tao WANG XueSong XIAO ShunPing School of Electronic Science and Engineering National University of Defense Technology Changsha 410073 China School of Electronic Engineering Naval University of Engineering Wuhan 430033 China

The statistical properties of the normalized stokes parameters in a Gaussian stochastic plane wave field are described in detail. Via the expression of the three normalized stokes parameters, the mean, variance, and high-order moments are calculated, which simplify C. Brosseau＇s results. The new dispersion, normalized contrast function, skewness, and kurtosis are defined to describe the non-Gaussian distribution characteristics, which can be applied to Gaussian wave fields relating to depolarization of light by a spatially random medium.

关键词： instantaneous polarization stokes vector statistical analysis the normalized stokes parameters

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