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Nonlinear correction of terahertz FMCW based on time-domain phase compensation

Optics Letters 2025年第8期50卷 2630-2633页

作者： Liang, Bin Shen, Sishi Wang, Tianyi Wang, Yue Hao, Congjing Liu, Defeng Liu, Jinsong Wang, Kejia Yang, Zhengang Wuhan National Laboratory for Optoelectronics School of Optical and Electronic Information Optics Valley Laboratory Huazhong University of Science and Technology Wuhan430074 China Huazhong Institute of Electro-Optics Wuhan430299 China AVIC Beijing Changcheng Aeronautical Measurement and Control Technology Research Institute Beijing101111 China

Terahertz frequency-modulated continuous-wave (THz FMCW) technology has become a widely used nondestructive testing tool due to its imaging and detection advantages. Nonlinearity is one of the most common problems with FMCW technology. This is due to the inability to maintain strict linearity during the high-frequency sweep process, resulting in multiple frequencies in the calculated intermediate frequency (IF) signal. This reduces the detection capability of the system, as the effective frequencies are swamped. This paper proposes a nonlinear correction method based on the time-domain phase compensation technique. The causes of nonlinear distortion are analyzed, and the corrected signal is obtained after phase compensation of the instantaneous time-domain signal. Experimental results obtained froman actual terahertz imaging system proved the effectiveness of the proposed method, achieving precise positioning of three-dimensional objects. The range resolution was improved by an order of magnitude, reaching the theoretical resolution of the experimental system. The method improves the detection accuracy of the system without the need for additional equipment. © 2025 Optica Publishing Group.

关键词： Terahertz waves

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Underwater arbitrary ranging based on chirped pulse interferometry with a mode-locked laser

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Journal of Lightwave technology 2025年

作者： Shi, Haonan Zhao, Haihan Xu, Xinyang Zhu, Zhiwei Zhai, Jingsheng Li, Xiaobo Tianjin University School of Marine Science and Technology Tianjin300072 China Research Institute of China Electronics Technology Group Corporation Science and Technology on Electro-Optical Information Security Control Laboratory No. 53 Tianjin300308 China The Chinese University of Hong Kong Department of Mechanical and Automation Engineering Hong Kong999077 Hong Kong Nanjing University of Aeronautics and Astronautics Key Laboratory of Space Photoelectric Detection and Perception Ministry of Industry and Information Technology Nanjing211106 China

Underwater distance measurement and length sensing, as fundamental functions of geoscience, are integrated into underwater robots and vessels in various forms of sensor payloads and play a crucial role in a wide range of remote sensing applications. Advanced laser-based detection systems and algorithms are essential for underwater tasks, such as detecting damage in underwater pipelines and conducting detailed structural health assessments. In this paper, we experimentally demonstrated an arbitrary underwater ranging system by the chirped pulse interferometry with a mode-locked laser. Water's inherent characteristic introduces dispersion, enabling unique distance discrimination. Adjusting the repetition frequency allows us to acquire the interference spectrum. A long fiber delay line, stabilized by the servo-controlled system, eliminates the ranging dead zone. The widest fringe of the interference spectrum, corresponding to an instantaneous repetition frequency, indicates the arbitrary measured distance. Leveraging a charge-coupled device detection module, we achieved an update rate of 13.5 Hz for the interference spectrum. Experimental results show a precise distance difference within 59.8 μm at the 5 m range underwater without the dead zone. © 2025 IEEE. All rights reserved.

关键词： Laser mode locking

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Research on the Construction of a Novel Cyberspace security Ecosystem

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Engineering 2018年第1期4卷 47-52页

作者： Xiao-Niu Yang Wei Wang Xiao-Feng Xu Guo-Rong Pang Chun-Lei Zhang Science and Technology on Communication Information Security Control Laboratory Jiaxing Zhejiang 314033 China Science and Technology on Electro-Optical Information Security Control Laboratory Tianfin 300300 China

Given the challenges facing the cyberspace of the nation, this paper presents the tripartite theory of cyberspace, based on the status quo of cyberspace. Corresponding strategies and a research architecture are proposed for common public networks （C space）, secure classified networks （S space）, and key infras- tructure networks （K space）, based on their individual characteristics. The features and security require- ments of these networks are then discussed. Taking C space as an example, we introduce the SMCRC （which stands for ＂situation awareness, monitoring and management, cooperative defense, response and recovery, and countermeasures and traceback＂） loop for constructing a cyberspace security ecosys- tem. Following a discussion on its characteristics and information exchange, our analysis focuses on the critical technologies of the SMCRC loop. To obtain more insight into national cyberspace security, special attention should be paid to global sensing and precise mapping, continuous detection and active manage- ment, cross-domain cooperation and systematic defense, autonomous response and rapid processing, and accurate traceback and countermeasure deterrence.

关键词： Cyberspace security ecosystem SMCRC loop Tripartite theory of cyberspace

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Widely Tunable Middle Infrared optical Parametric Oscillator Pumped by the Q-Switched Ho：GdVO_4 Laser

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Chinese Physics Letters 2018年第5期35卷 48-51页

作者： Xiao-Ming Duan Cheng Chen Yu Ding Bao-Quan Yao Yue-Zhu Wang National Key Laboratory of Tunable Laser Technology Harbin Institute of Technology Harbin 150001 Science and Technology on Electro-Optical Information Security Control Laboratory Tianjin 300308

We demonstrate a middle infrared ZnGeP_2 optical parametric oscillator pumped by the Q-switched Ho：GdVO_4 laser. When the incident Ho pump power is 4.12 W, the maximum average output power of the ZGP-OPO laser is 2.05 W, corresponding to a slope efficiency of 74.6%. The ZGP-OPO laser produces 4.2 ns mid-infrared pulses at a pulse repetition rate of 5 kHz. In addition, we obtain 0.8 um of tunable range for the signal wave and 2.1 um of tunable range for the idler wave.

关键词： Ho OPO Widely Tunable Middle Infrared optical Parametric Oscillator Pumped by the Q-Switched Ho:GdVO4 Laser

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Fast Fourier single-pixel imaging based on Sierra–Lite dithering algorithm

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Chinese Physics B 2019年第6期28卷 189-194页

作者： Zhen-Yu Liang Zheng-Dong Cheng Yan-Yan Liu Kuai-Kuai Yu Yang-Di Hu National University of Defense Technology State Key Laboratory of Pulsed Power Laser TechnologyHefei 230037China Science and Technology on Electro-Optical Information Security Control Laboratory Tianjin 300000China

The single-pixel imaging(SPI) technique is able to capture two-dimensional(2 D) images without conventional array sensors by using a photodiode. As a novel scheme, Fourier single-pixel imaging(FSI) has been proven capable of reconstructing high-quality images. Due to the fact that the Fourier basis patterns(also known as grayscale sinusoidal patterns)cannot be well displayed on the digital micromirror device(DMD), a fast FSI system is proposed to solve this problem by binarizing Fourier pattern through a dithering algorithm. However, the traditional dithering algorithm leads to low quality as the extra noise is inevitably induced in the reconstructed images. In this paper, we report a better dithering algorithm to binarize Fourier pattern, which utilizes the Sierra–Lite kernel function by a serpentine scanning method. Numerical simulation and experiment demonstrate that the proposed algorithm is able to achieve higher quality under different sampling ratios.

关键词： single-pixel imaging binary Fourier basis pattern the dithering algorithm

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Temperature control system of air-conditioning based on the fuzzy theory

Temperature control system of air-conditioning based on the ...

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2011 IEEE International Conference on Mechatronics and Automation, ICMA 2011

作者： Jing, Jiang Xuesong, Zhang Science and Technology on Electro-optical Information Security Control Laboratory Beijing China Science and Technology on Electro-optical Information Security Control Laboratory Northeast Institute of Electronics Technology Hebei China

ISBN: (纸本)9781424481149

Two-dimensional fuzzy temperature controller was used in the system of inverter air-conditioner to control the room temperature. Self-adjustment PID fuzzy controller was proposed to realize real-time control function. V/F control mode was used to compensate with low voltage, the average sampling algorithm was proposed to implement SPWM waveform modulation. Finally, the feasibility of self-adjustment PID fuzzy controller was verified by simulation, the actual operation results had proved that self-adjustment PID fuzzy controller had reliable, good output waveform and small harmonic wave, which could meet operational requirements of inverter air-conditioner. © 2011 IEEE.

关键词： Air conditioning

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All solid state Mid-IR laser

All solid state Mid-IR laser

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2011 Academic International Symposium on Optoelectronics and Microelectronics technology, AISOMT 2011

作者： Xiao-Juan, Zhang Hai-Bo, Yang Hong, Xu Jun, Cai Science and Technology on Electro-Optical Information Security Control Laboratory Hebei China

ISBN: (纸本)9781457707964

A Tm laser pumped Mid-IR all solid-state laser is reported. A thulium laser is used to directly drive a ZnGeP2 optical parametric oscillator (OPO) with 1.99μm output to generate the 3∼5μm wavelength. Diode pumped Tm:YAP laser operates on 1.99μm, repetition frequency of 10KHz, the optical to optical conversion efficiency is 28%. The all solid-state Mid-IR laser runs at room temperature and achieves over 1W at 3∼5μm with an optical to optical conversion efficiency of 5.4% starting from the pump diode. © 2011 IEEE.

关键词： optical parametric oscillators

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Teachers cooperation:team-knowledge distillation for multiple cross-domain few-shot learning

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Frontiers of Computer science 2023年第2期17卷 91-99页

作者： Zhong JI Jingwei NI Xiyao LIU Yanwei PANG School of Electrical and Information Engineering Tianjin UniversityTianjin 300072China Science and Technology on Electro-Optical Information Security Control Laboratory Tianjin 300308China Tianjin Key Laboratory of Brain-Inspired Intelligence Technology Tianjin 300072China

Although few-shot learning(FSL)has achieved great progress,it is still an enormous challenge especially when the source and target set are from different domains,which is also known as cross-domain few-shot learning(CD-FSL).Utilizing more source domain data is an effective way to improve the performance of ***,knowledge from different source domains may entangle and confuse with each other,which hurts the performance on the target ***,we propose team-knowledge distllation networks(TKD-Net)to tackle this problem,which explores a strategy to help the cooperation of multiple ***,we distill knowledge from the cooperation of teacher networks to a single student network in a meta-learning *** incorporates task-oriented knowledge distillation and multiple cooperation among teachers to train an efficient student with better generalization ability on unseen ***,our TKD-Net employs both response-based knowledge and relation-based knowledge to transfer more comprehensive and effective *** experimental results on four fine-grained datasets have demonstrated the effectiveness and superiority of our proposed TKD-Net approach.

关键词： cross-domain few-shot learning meta-learning knowledge distillation multiple teachers

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Design of the linear array CCD acquisition system that line frequency and integration time adjustable

Design of the linear array CCD acquisition system that line ...

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International Conference on electronics and Optoelectronics

作者： Hu, Tao Chen, Ya-Nan Science and Technology on Electro-Optical Information Security Control Laboratory Sanhe Hebei China

ISBN: (纸本)9781612842738

Linear array CCD acquisition system is generally used for high precision measurement and control field. In this paper, firstly introduce a design of linear array CCD acquisition system that provide two features of adjustable line frequency and integration time, and secondly present linear array CCD acquisition system components, linear array CCD device principles, timing-driven design, signal processing circuit and data acquisition circuit, then highlights the linear array CCD timing-driven design, the design of line frequency and integration time adjustable, and illustrate the advantages of the system such as the convenience, the agility and the reliability, etc. © 2011 IEEE.

关键词： Data acquisition

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SDM-based electronic defense intelligent networking technology 8

SDM-based electronic defense intelligent networking technolo...

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8th Symposium on Novel Photoelectronic Detection technology and Applications

作者： Ma, Baoqiang Liu, Tongyu Yong, Zhang Shuai, Jia Dong, Liu Science and Technology on Electro-Optical Information Security Control Laboratory Tianjin300308 China

ISBN: (数字)9781510653122

ISBN: (纸本)9781510653115

With the increasingly prominent role of high-tech weapons in modern warfare, electronic warfare has also become a topic that has attracted worldwide attention. At present, global electronic warfare is in an important period of transformation and development. In particular, the US military has made substantial progress in electronic warfare in recent years. The development of electronic defense has played a decisive role in future wars[1]. This article introduces the application system architecture and operating mechanism of SDM. At the same time, it introduces the application of plug-and-play SDM software in modern electronic defense system operations, and expounds the role of intelligent command in future electronic warfare. SDM software can realize the plug-and-play of sensor equipment, and it plays a key role in the intelligent network of electronic defense. © 2022 SPIE

关键词： electronic warfare

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