2023

• Record 229 of
  
  Title:A 400-Gb/s 64-QAM Optical Receiver with Monolithically Integrated TIA and Balanced-PD in 45-nm SOI CMOS
  
  Author(s):Xiong, Yongliang(1,2); Yang, Yihao(3,5); Ma, Qianli(2,4); Ren, Yangming(3,5); Li, Leliang(2,4); Li, Guike(2,4); Liu, Jian(2,4); Li, Yingtao(1); Wang, Binhao(3,5); Qi, Nan(2,4); Liu, Liyuan(2,4)
  Source: Proceedings of 2023 IEEE International Conference on Integrated Circuits, Technologies and Applications, ICTA 2023  Volume: null  Issue: null  Article Number: null  DOI: 10.1109/ICTA60488.2023.10364315  Published: 2023  
  Abstract:This paper presents an analog coherent receiver front-end for high-speed optical links. By monolithically integrating two silicon photonic (Si-Ph) photodetectors (PD) with a differential-input transimpedance amplifier (TIA), a balanced topology and high receiving common-mode rejection ratio (CMRR) is realized. An inverter-based linear TIA with shunt-series multiple peaking is proposed to enable the high-order quadrature amplitude modulation (QAM). Simulation results show the TIA achieves 41 GHz bandwidth, 12.3 pA Hz input referred noise. Implemented in a 45 nm Si-Ph CMOS process, the optical receiver reaches 400-Gb/s channel speed with 64-QAM modulation, at the cost of only 1.8495mm2 chip area and 18.3 mW power consumption. © 2023 IEEE.
  Accession Number: 20240415432919
• Record 230 of
  
  Title:Precision Improvement of Underwater Single Photon Imaging Based on Model Matching
  
  Author(s):Zhang, Zhenyang(1,2); Chen, Songmao(2,3); Wang, Jie(1,2); Ma, Caiwen(2,4); Su, Xiuqin(1,2)
  Source: IEEE Photonics Technology Letters  Volume: 35  Issue: 5  Article Number: null  DOI: 10.1109/LPT.2023.3238079  Published: March 1, 2023  
  Abstract:In this letter, the Gaussian With Exponential Components (GWEC) model is proposed to simulate the Instrument Response Function (IRF) by the convolution of the conventional Gaussian and exponential models, which aims to solve the issue that the system failed to obtain IRF accurately, resulting in poor accuracy of the cross-correlation results. Meanwhile, the GWEC model takes the advantage of simplicity in parameter setting and high range accuracy after cross-correlation operation. © 1989-2012 IEEE.
  Accession Number: 20230613543063
• Record 231 of
  
  Title:Compensation Control Strategy for Photoelectric Stabilized Platform Based on Disturbance Observation
  
  Author(s):Chang, Sansan(1,2,5); Cao, Jianzhong(1,5); Pang, Ji(3); Zhou, Feihang(3); Cheng, Gong(4); Chen, Weining(1,4,5)
  Source: SSRN  Volume: null  Issue: null  Article Number: null  DOI: 10.2139/ssrn.4654494  Published: December 5, 2023  
  Abstract:The accuracy and stability of the photoelectric stabilized platform will be inevitably affected by the friction disturbance and the base platform disturbance in the actual operation. To improve the disturbance rejection performance, two kinds of the disturbance observers are employed and compared in this paper, include the adaptive proportion-integrator observer and the robust sliding mode observer. The disturbances of the friction torque and the moving base are observed, then these observed values are compensated to the voltage loop by the feedback and feedforward, respectively. While the disturbances of the friction torque and the shaking base are compensated, the parameters of the speed stability loop are also tuned to improve the performance of this photoelectric stabilized platform. Finally, the effectiveness of the proposed method is verified by both simulations and experiments. The results show that the proposed disturbance compensation control method based on the sliding mode observer has strong robustness and can effectively reduce the impact of system disturbances. © 2023, The Authors. All rights reserved.
  Accession Number: 20230443370
• Record 232 of
  
  Title:Visual attention-based siamese CNN with SoftmaxFocal loss for laser-induced damage change detection of optical elements
  
  Author(s):Kou, Jingwei(1,2); Zhan, Tao(3); Zhou, Deyun(1); Xie, Yu(4); Da, Zhengshang(2); Gong, Maoguo(5)
  Source: Neurocomputing  Volume: 517  Issue: null  Article Number: null  DOI: 10.1016/j.neucom.2022.10.074  Published: January 14, 2023  
  Abstract:With high-energy laser irradiating, the laser-induced damages may occur in the surfaces of optical elements in laser facilities. As the laser-induced damage changes can badly affect regular and healthy operation of laser facilities, it is essential to effectively detect real damage changes while suppressing meaningless and spurious changes in captured optical images. In order to achieve high-precision laser-induced damage change detection, this paper presents a novel deep learning model which exploits visual attention-based siamese convolutional neural network with SoftmaxFocal loss and significantly improves the performance of damage change detection. In the proposed model, an end-to-end classification network is designed and trained which fuses the spatial-channel domain collaborative attention modules into siamese convolutional neural network thus achieving more efficient feature extraction and representation. For the purpose of addressing the unbalanced distribution of hard and easy samples, a novel loss function which is termed as SoftmaxFocal loss is put forward to train the proposed network. The SoftmaxFocal loss creatively introduces an additive focusing term into original softmax loss which greatly enhances the online hard sample mining ability of the proposed model. Experiments conducted on three real datasets demonstrate the validity and superiority of the proposed model. © 2022 Elsevier B.V.
  Accession Number: 20224513072238
• Record 233 of
  
  Title:Identity Feature Disentanglement for Visible-Infrared Person Re-Identification
  
  Author(s):Chen, Xiumei(1,2,3); Zheng, Xiangtao(3,4); Lu, Xiaoqiang(3,4)
  Source: ACM Transactions on Multimedia Computing, Communications and Applications  Volume: 19  Issue: 6  Article Number: 201  DOI: 10.1145/3595183  Published: July 12, 2023  
  Abstract:Visible-infrared person re-identification (VI-ReID) task aims to retrieve persons from different spectrum cameras (i.e., visible and infrared images). The biggest challenge of VI-ReID is the huge cross-modal discrepancy caused by different imaging mechanisms. Many VI-ReID methods have been proposed by embedding different modal person images into a shared feature space to narrow the cross-modal discrepancy. However, these methods ignore the purification of identity features, which results in identity features containing different modal information and failing to align well. In this article, an identity feature disentanglement method is proposed to disentangle the identity features from identity-irrelevant information, such as pose and modality. Specifically, images of different modalities are first processed to extract shared features that reduce the cross-modal discrepancy preliminarily. Then the extracted feature of each image is disentangled into a latent identity variable and an identity-irrelevant variable. In order to enforce the latent identity variable to contain as much identity information as possible and as little identity-irrelevant information, an ID-discriminative loss and an ID-swapping reconstruction process are additionally designed. Extensive quantitative and qualitative experiments on two popular public VI-ReID datasets, RegDB and SYSU-MM01, demonstrate the efficacy and superiority of the proposed method. © 2023 Copyright held by the owner/author(s). Publication rights licensed to ACM.
  Accession Number: 20233414595186
• Record 234 of
  
  Title:Modeling and analysis of fast steering mirror disturbance effects on the line of sight jitter for precision pointing and tracking system
  
  Author(s):Lv, Tao(1,2,3,4); Ruan, Ping(2,3); Jiang, Kai(2,3); Jing, Feng(2,3)
  Source: Mechanical Systems and Signal Processing  Volume: 188  Issue: null  Article Number: 110002  DOI: 10.1016/j.ymssp.2022.110002  Published: April 1, 2023  
  Abstract:Fast steering mirrors (FSMs) are typically applied for beam stabilization for precision pointing and tracking systems (PPTSs) owing to their high-bandwidth, high-resolution, and high accuracy. In addition to the advantages, the presence of the residual momentum which caused by FSMs’ operation usually has noticeable effects on the stabilization of the line of sight (LOS) for PPTSs. Hence, it is necessary and momentous to estimate the effects of these disturbances to give insight into the FSM specification and the PPTS structural performance. However, the characteristic of multidisciplinary coupling makes it a challenge to measure the LOS jitter caused by FSMs. We approach this problem by establishing an integrated model for estimating the LOS jitter. A dynamic model of an FSM is firstly built to value the unbalanced momentum generated from its motion. Then a finite element model for the structure of the tracking system is established to predict the dynamic response excited by the disturbances from the FSM. In addition, with a linear optical model, the system optical performance under the FSM's disturbances is determined. Finally, a test is conducted to verify the validity of the model and the analysis. This paper focuses on estimating the disturbances effects of the FSM on the LOS jitter for a PPTS, and providing potential approaches for reducing these effects. © 2022 Elsevier Ltd
  Accession Number: 20225113272435
• Record 235 of
  
  Title:Theoretical study on time response of semiconductor photorefractive effects under subpicosecond ultra-fast X-rays
  
  Author(s):Zhou, Hao(1,2,3); Huang, Qi(1,2,3); He, Kai(4); Gao, GuiLong(4); Yan, Xin(4); Yao, Dong(4); Wang, Tao(4); Tian, Jinshou(4); Hu, RongHao(1,2,3); Lv, Meng(1,2,3)
  Source: Philosophical Transactions of the Royal Society A: Mathematical, Physical and Engineering Sciences  Volume: 381  Issue: 2253  Article Number: 20220213  DOI: 10.1098/rsta.2022.0213  Published: August 21, 2023  
  Abstract:A theoretical model that can efficiently calculate the refractive index response of semiconductors under ultrafast X-ray radiation is established based on the photorefractive effect of semiconductors. The proposed model is used to interpret X-ray diagnostics experiments, and the results are in good agreement with experiments. In the proposed model, a rate equation model of free carrier density calculation is adopted with the X-ray absorption cross-sections calculated by atomic codes. The two-temperature model is used to describe the electron-lattice equilibration and the extended Drude model is applied to calculate the transient refractive index change. It is found that faster time response can be achieved for semiconductors with shorter carrier lifetime and sub-picosecond resolution can be obtained for InP and Al0.5Ga0.5As. The material response time is not sensitive to X-ray energy and the diagnostics can be used in the 1-10 keV energy range. This article is part of the theme issue 'Dynamic and transient processes in warm dense matter'. © 2023 The Author(s).
  Accession Number: 20233014435629
• Record 236 of
  
  Title:Dynamic Characteristics Analysis of Space Electro-optical Tracking and Pointing Turntable
  
  Author(s):Peng, Jiali(1,2,3); Ruan, Ping(1,3); Xie, Youjin(1,3); Li, Zhiguo(1,3); Wang, Jiahao(1,2,3); Han, Jingyu(1,2,3)
  Source: Guangzi Xuebao/Acta Photonica Sinica  Volume: 52  Issue: 7  Article Number: 0712002  DOI: 10.3788/gzxb20235207.0712002  Published: July 2023  
  Abstract:The space electro-optical tracking and pointing turntable is a kind of space photoelectric payload，which is used to realize the stability of the optical axis and the tracking of the target in the space environment. In the process of launching，the turntable must endure many harsh mechanical environments such as vibration and shock，therefore，its dynamic characteristics directly determine the reliability of the turntable. When we use finite element method to analyze the dynamic characteristics，a finite element model that can accurately reflect the stiffness and damping characteristics of the turntable is the key to the analysis. The stiffness of the connected parts in the turntable，such as bearings and locking devices，has a great influence on the stiffness characteristics of the overall structure. In the current research，there is a distortion problem in the finite element modeling of bearings and locking devices. Aiming at this problem，this paper proposes an equivalent modeling method for bearing and locking devices by using generalized spring elements （bushing），which represents the behavior of a flexible connection or joint that allows translational and rotational movement. The translational degrees of freedom allow movement along the X，Y，and Z axes，representing the linear displacements in those directions，the rotational degrees of freedom allow rotation around the X，Y，and Z axes. We analyze the bearings and locking devices under dynamic load，establish their mechanical models，and define the significance of the Bushing elements stiffness matrix parameters. Then we simplify the structure of turntable，complete the equivalent modeling for shafting and locking devices by using Bushing elements，establish the finite element model of the turntable. Afterwards，we calculate a partial of bearing stiffness parameters based on Hertz contact theory. The remaining bearing stiffness parameters and all locking devices stiffness parameters that can not be theoretically calculated are obtained by parameter identification based on modal test data. Due to the stiffness of the bearings and locking devices decoupled from each other，we set up three different working conditions of modal test to obtain them. We use condition 1（all locking devices：unlocked）to obtain the stiffness parameters of azimuth shafting and pitching shafting，condition 2（azimuth locking devices：unlocked；pitching locking device：locked）to obtain the stiffness parameters of pitching locking device，and condition 3（all locking devices：locked）to obtain the stiffness parameters of azimuth locking devices. Based on the obtained stiffness parameters，modal analysis is performed，the maximum relative error in natural frequencies between simulation and test is 5.1%，within the allowable margin. Finally，since the damping in the turntable system is a frequency-dependent damping，the constant damping used in traditional finite element analysis does not reflect real damping characteristics，we define damping characteristics of turntable by using modal damping. Modal damping is a frequency-dependent type of damping in finite element analysis，and suppresses responses by defining damping to each mode shape. Because of the superposition principle of damping effect，we use the maximum response of the X，Y，and Z directions in the 0.2 g swept-sine vibration test to identification the modal damping based on the constant damping of 0.02. Based on the obtained modal damping， harmonic response analysis is performed，the maximum relative error in the maximum responses of the X，Y，and Z directions between simulation and test is 3.2%，within the allowable margin. Hence the stiffness and damping parameters analysis of turntable is accurate，and the dynamic characteristics analysis is accurate. The results show that the method of using Bushing elements to model the bearing and locking devices equivalently can reflect the dynamic characteristics of the turntable more accurately than traditional modeling methods， and the methods of obtaining the stiffness and damping characteristics through theoretical calculation and parameter identification are feasible. It has a certain reference effect on the modeling and simulation of the same type of turntable. © 2023 Chinese Optical Society. All rights reserved.
  Accession Number: 20233714721514
• Record 237 of
  
  Title:Hyperspectral and LiDAR Representation With Spectral-Spatial Graph Network
  
  Author(s):Du, Xingqian(1,2); Zheng, Xiangtao(3); Lu, Xiaoqiang(3); Wang, Xin(4)
  Source: IEEE Journal of Selected Topics in Applied Earth Observations and Remote Sensing  Volume: 16  Issue: null  Article Number: null  DOI: 10.1109/JSTARS.2023.3321776  Published: 2023  
  Abstract:Land cover analysis has received significant attention in remote sensing-related fields. To take advantage of multimodal data, hyperspectral images (HSI) and light detection and ranging (LiDAR) are often combined. However, it is difficult to capture intricate local and global spectral-spatial associations between HSI and LiDAR. To exploit the complementary information of multimodal data, a spectral-spatial graph network is proposed that integrates HSI and LiDAR data into intricate local and global spectral-spatial associations. Specifically, the network consists of a local module and a global module. The local module uses convolution techniques applied over image patches to preserve the local spatial relationships available in multimodal data. The global module constructs a spectral-spatial multimodal graph, which is used to preserve spectral-spatial proximity in multimodal data. Both the local and global modules are utilized to their utmost capacity to generate the final multimodal data representation. Experiments on multimodal remote sensing datasets reveal that the proposed network has attained performance levels comparable to state-of-the-art methods. © 2008-2012 IEEE.
  Accession Number: 20234314966856
• Record 238 of
  
  Title:Harvey-Shack theory for a converging-diverging Gaussian beam
  
  Author(s):Ma, Zhanpeng(1,2,3,4); Hansen, Poul-Erik(3); Wang, Hu(1,2); Karamehmedović, Mirza(4); Chen, Qinfang(1)
  Source: Journal of the Optical Society of America B: Optical Physics  Volume: 40  Issue: 5  Article Number: null  DOI: 10.1364/JOSAB.478801  Published: May 2023  
  Abstract:The scattering characteristics of random rough surfaces illuminated with a 3D converging-diverging Gaussian beam are investigated by applying the conventional Harvey-Shack theory in conjunction with 2D plane-wave decomposition. The Gaussian beam is assumed to have an arbitrary angle of incidence and to be linearly s-polarized. Using data obtained from laser BRDF measurements on isotropic random rough surfaces with low surface roughness, we demonstrate that the Gaussian beam Harvey-Shack theory is in better accordance with the experimental data than the conventional Harvey-Shack theory. The two models become identical for a large beam waist radii but are significantly different for smaller ones. © 2023 Optica Publishing Group under the terms of the Optica Open Access Publishing Agreement.
  Accession Number: 20231914078637
• Record 239 of
  
  Title:Optimization of the quality control parameters in sapphire single crystal preparation using the Kyropoulos method
  
  Author(s):Xu, Jia(1); Qiao, Tiezhu(1,2); Dong, Huijie(2); Zhang, Haifeng(3); Yan, Gaowei(4)
  Source: CrystEngComm  Volume: 25  Issue: 7  Article Number: null  DOI: 10.1039/d2ce01675c  Published: January 25, 2023  
  Abstract:The production of sapphire single crystals with high quality and low cost is an important goal of the sapphire industry. The quality of seeding has a direct impact on the final growth quality of sapphire crystals when sapphire is prepared using the Kyropoulos method. Keeping the crystal/melt contact stable is essential for lowering the number of seeding defects. In order to reduce the preparation cost of sapphire, an optimization strategy integrating computational fluid dynamics, artificial neural networks, and genetic algorithm is proposed to optimize the growth parameters of crystal seeding. The optimization goals are to stabilize the crystal/melt growth interface and increase seeding effectiveness. Three growth parameters, namely, melt temperature, seed crystal rotation speed and pulling speed, are selected as optimization variables. The samples produced by numerical calculation are combined with the actual production data to train and test the neural networks. The genetic algorithm is coupled with artificial neural networks to solve the multi-objective conflict between improving seeding efficiency and reducing the formation of crystal defects in the seeding process. The influence of the mechanism of different combinations of seeding parameters on seeding quality is discussed, and the optimization of seeding growth process is realized. The results show that the optimized combination of parameters gained in this study can improve the seeding speed and ensure the stability of the solid-liquid interface. This work is helpful to reduce the formation of seeding defects, improve the seeding quality, and shorten the seeding time. © 2023 The Royal Society of Chemistry
  Accession Number: 20230613537564
• Record 240 of
  
  Title:Study of Sub-Pixel Gray Degree Reconstruction Method for Simulation of Faint Star Element Target Position
  
  Author(s):Wu, Linghao(1); Wang, Jiaan(1); Jia, Wentao(2); Zhang, Jian(3); Sun, Jingrui(3)
  Source: SSRN  Volume: null  Issue: null  Article Number: null  DOI: 10.2139/ssrn.4423797  Published: April 19, 2023  
  Abstract:The simulation accuracy of the faint star element target (FSET) position is a key factor that affects the accuracy of the precision test of the star sensor. In order to solve the problem that the position accuracy of FSET is restricted by the size of its component elements, the mathematical representation of FSET position correction and the grayscale distribution of the component elements is derived, and the Gaussian radius and grayscale energy coefficient model of FSET is established. According to the measured distribution results of the position error of the full-field FSET, the gray distribution of the basic element is reconstructed by reconstructing each correction set to simulate FSET, and the correction accuracy of the sub-pixel level FSET position is realized. The experimental results show that, compared with the existing correction methods, the position accuracy of FSET is improved by 1.64 times after subpixel gray reconstruction. © 2023, The Authors. All rights reserved.
  Accession Number: 20230133034