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Ultralow-phase-noise and broadband frequency-hopping coupled optoelectronic oscillator under quiet point operation

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photonics Research 2024年第08期12卷 1785-1793页

作者： HUI LIU MINGYANG GUO TIAN ZHANG JIAN DAI KUN XU state key laboratory of information photonics and optical communications Beijing University of Posts and Telecommunications school of Electronic Engineering Beijing University of Posts and Telecommunications

Advancements in microwave photonics have yielded novel approaches for generating high-purity microwave sources. Among these, optoelectronic oscillators（OEOs） and coupled optoelectronic oscillators（COEOs） have demonstrated the capability to generate frequency-independent microwaves with exceptionally low phase ***, the tunability of the oscillators is rather limited due to the necessity for narrowband electronic bandpass filters, presenting challenges in achieving both wide and rapid tuning capabilities. Here, we present a COEO featuring ultralow phase noise, flexible tuning capability, and high robustness. This is achieved through a quiet point（QP）-operated harmonic mode-locked fiber laser, which effectively mitigates optical amplifier noise and supermode competition, thus significantly diminishing the necessity for ultra-narrow electronic filters. Due to the liberated tuning ability, we present an oscillator that can be tuned from 2 GHz to 18 GHz, with phase noise as low as-140 d Bc/Hz at 10 k Hz under the QP operation. We then illustrate the practical application of the proposed oscillator in generating frequency-hopping signals with consistent spurious modes less than-85 d Bc,absolute phase noise below-135 d Bc/Hz at 10 k Hz, hopping resolution of 1.25 MHz, and fractional frequency stability below 6.1 × 10-12at 1 s averaging time when locked to a reference. The presented COEO structure emerges as a compelling solution for agile and low-noise microwave sources in advanced wireless communication and radar systems.

关键词： Bandpass filters Beam splitters Microwave photonics Mode-locked fiber lasers optical amplifiers Phase noise

Optimizing depth of field in 3D light-field display by analyzing and controlling light-beam divergence angle

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Chinese Optics Letters 2024年第1期22卷 14-20页

作者：于迅博王一平高鑫李涵宇刘柯新颜玢玢桑新柱 state key laboratory of information photonics and optical communications Beijing University of Posts and Telecommunications(BUPT)Beijing 100876China

A concept of divergence angle of light beams(DALB)is proposed to analyze the depth of field(DOF)of a 3D light-field display *** mathematical model between DOF and DALB is established,and the conclusion that DOF and DALB are inversely proportional is *** reduce DALB and generate clear depth perception,a triple composite aspheric lens structure with a viewing angle of 100°is designed and experimentally *** DALB-constrained 3D light-field display system significantly improves the clarity of 3D images and also performs well in imaging at a 3D scene with a DOF over 30 cm.

关键词： 3D light-field display depth of field divergence angle of light beams compound lens

Road map for, and technical challenges of, carbon-nanotube integrated circuit technology

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National science Review 2024年第3期11卷 14-16页

作者： Jia Si Panpan Zhang Zhiyong Zhang key laboratory for the Physics and Chemistry of Nanodevices and Center for Carbon-based Electronics School of Electronics Peking University state key laboratory of information photonics and optical communications Beijing University of Posts and Telecommunications

The past decade has witnessed an explosion of research on carbon-nanotube(CNT) electronics due to their outstanding properties, including an ultrathin body, a high carrier mobility and a high saturation velocity.

关键词： TRANSISTORS

An isolated symmetrical 2T2R cell enabling high precision and high density for RRAM-based in-memory computing

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science China(information sciences) 2024年第5期67卷 287-294页

作者： Yaotian LING Zongwei WANG Yuhang YANG Lin BAO Shengyu BAO Qishen WANG Yimao CAI Ru HUANG school of Integrated Circuits Beijing Advanced Innovation Center for Integrated Circuits Peking University state key laboratory of information photonics and optical communications Beijing University of Posts and Telecommunications

In-memory computing(IMC), leveraging emerging memories, holds significant promise in overcoming memory limitations and improving energy efficiency. However, the prevailing IMC array structure based on serially connected transistors and memory cells(1T1R/2T2R), along with the signed weight mapping scheme, can lead to asymmetrical weight sensing issues(AWS) due to electrical asymmetry within the1T1R/2T2R structure, particularly in highly scaled cells where the transistor's resistance becomes significant. In this paper, we propose and fabricate an electrically symmetric memory cell based on a physically isolated 2T2R structure for IMC. This design aims to enhance the precision and density of RRAM-based IMC arrays. The 2T2R cells are manufactured using the back-end-of-line(BEOL) process of a commercial40 nm technology platform. The feasibility of this design is verified through measured and simulated results,showcasing its capability to address the issue of AWS. Compared to conventional 2T2R cells, this design achieves a considerably smaller transistor footprint without compromising accuracy, while also improving integration density by 42.2%. These innovative memory cell advancements have the potential to further advance high-energy-efficient IMC technology.

关键词： RRAM 2T2R multi-level storage weight asymmetry in-memory computing

Multifunctional MXene/rGO aerogels loaded with Co/MnO nanocomposites for enhanced electromagnetic wave absorption,thermal insulation and pressure sensing

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Nano Research 2024年第9期17卷 7803-7813页

作者： Chan Guo Shiping Shao Xin Zhang Yunxiang Tang Luxue Wang Jiurong Liu Lili Wu Ke Bi Fenglong Wang key laboratory for Liquid-Solid Structural Evolution and Processing of Materials Ministry of Education Shandong UniversityJinan 250061China state key laboratory of information photonics and optical communications School of ScienceBeijing University of Posts and TelecommunicationsBeijing 100876China

Aerogel-based composites hold promising application prospects as potential electromagnetic wave(EMW)absorption materials,yet the construction of such materials with ingenious microstructures,appropriate magnetic/dielectric multi-components,and integrated multifunctionality remains considerably ***,a multicomponent Co/MnO/Ti_(3)C_(2)T_(x) MXene/rGO(CMMG)hybrid aerogel featured with three-dimensional(3D)vertical directional channel architecture is *** from the synergistic effect arising from the 3D conductive networking structure,diverse heterogeneous interfaces,magnetic/dielectric multicomponent,and multiple loss pathways,the optimized CMMG-2 aerogel delivers fascinating EMW absorption capabilities,characterized by a minimal reflection loss(RL_(min))of-77.41 dB and an effective absorption bandwidth(EAB)of 6.56 ***,the remarkable hydrophobicity,exceptional thermal insulation capabilities,and outstanding photothermal properties of CMMG-2 aerogel make it highly promising for multiple application in diverse and demanding ***,the distinctive pore structure of hybrid aerogel also allows it for sensitive and reliable detection of electrical signals caused by pressure changes and human ***,this research provides a viable design strategy for the development of lightweight,efficient,and multifunctional aerogel-based EMW absorption materials for various application scenarios.

关键词： electromagnetic wave absorption Ti_(3)C_(2)qT_(x)MXene reduced graphene oxide magnetic-dielectric nanoparticles multifunctional aerogel

Experimental demonstration of a quantum downstream access network in continuous variable quantum key distribution with a local local oscillator

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photonics Research 2024年第6期12卷 1262-1273页

作者： DENGKE QI XIANGYU WANG ZHENGHUA LI JIAYU MA ZIYANG CHEN YUEMING LU SONG YU state key laboratory of information photonics and optical communications Beijing University of Posts and TelecommunicationsBeijing 100876China key laboratory of Trustworthy Distributed Computing and Service(MoE) Beijing University of Posts and TelecommunicationsBeijing 100876China state key laboratory of Advanced optical Communication Systems and Networks School of Electronicsand Center for Quantum Information TechnologyPeking UniversityBeijing 100871China

Quantum networks provide opportunities and challenges across a range of intellectual and technical frontiers,including quantum computation,communication,and *** traditional communication networks,quantum networks utilize quantum bits rather than classical bits to store and transmit *** key distribution(QKD)relying on the principles of quantum mechanics is a key component in quantum networks and enables two parties to produce a shared random secret key,thereby ensuring the security of data *** this work,we propose a cost-effective quantum downstream access network structure in which each user can get their corresponding key information through terminal *** on this structure,we demonstrate the first four-end-users quantum downstream access network in continuous variable QKD with a local local *** contrast to point-to-point continuous variable QKD,the network architecture reevaluates the security of each user and accounts for it accordingly,and each user has a lower tolerance for excess noise as the overall network expands with more ***,the feasibility of the experiment is based on the analysis of the theoretical model,noise analysis,and multiple techniques such as the particle filter and adaptive equalization algorithm used to suppress excess *** results show that each user can get a low level of excess noise and can achieve secret key rates of 546 kbps,535 kbps,522.5 kbps,and 512.5 kbps under a transmission distance of 10 km,respectively,with the finite-size block of 1×10~*** not only verifies the good performance but also provides the foundation for the future multi-user quantum downstream access networks.

关键词： quantum oscillator local

Investigation and mitigation of Mott neuronal oscillation fluctuation in spiking neural network

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science China(information sciences) 2024年第2期67卷 291-301页

作者： Lindong WU Zongwei WANG Lin BAO Linbo SHAN Zhizhen YU Yunfan YANG Shuangjie ZHANG Guandong BAI Cuimei WANG John ROBERTSON Yuan WANG Yimao CAI Ru HUANG school of Integrated Circuits Peking University Beijing Advanced Innovation Center for Integrated Circuits state key laboratory of information photonics and optical communications Beijing University of Posts and Telecommunications Department of Engineering University of Cambridge

Mott devices, featuring low hardware cost and high energy efficiency, have been demonstrated as a key oscillatory element in artificial neurons to enable spiking neural networks(SNNs) such as conversionbased SNNs(CSNNs). However, there will be inevitably non-ideal fluctuation in the oscillation behavior,causing the accuracy degradation of networks. In this paper, we investigate the Mott neuronal oscillation fluctuation(NOF) through experiments and modeling. The results show that the NOF phenomenon conforms to Gaussian distribution and originates from thermal fluctuation induced switching voltage variations. We construct a two-layer CSNN for image recognition tasks to study the NOF effect and propose the activation function boundary(AFB) method to strengthen the stability of the network. The results indicate that AFB can improve the accuracy of CSNN by up to 15.5% by tightening output distribution.

关键词： Mott neuron oscillation fluctuation variation-aware Mott neuronal model conversion-based spiking neural network activation function boundary

Tunable artificial plasmonic nanolaser with wide spectrum emission operating at room temperature

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Chinese Physics B 2024年第5期33卷 466-471页

作者：周鹏郭佳琦梁琨金磊梁熊玉李俊强邓绪彦秦建宇张家森于丽 state key laboratory of information photonics and optical communications School of ScienceBeijing University of Posts and TelecommunicationsBeijing 100876China state key laboratory for Artificial Microstructures and Mesoscopic Physics School of PhysicsPeking UniversityBeijing 100876China Peking University Yangtze Delta Institute of Optoelectronics Peking UniversityNantong 226010China

With the rapid development of information and communication technology,a key objective in the field of optoelectronic integrated devices is to reduce the nano-laser size and energy *** nanolasers are unable to exceed the diffraction limit and typically exhibit low modulation rates of several *** contrast,plasmonic nanolaser utilizes highly confined surface plasmon polariton(SPP)mode that can exceed diffraction limit and their strong Purcell effect can accelerate the modulation rates to several ***,we propose a parametrically tunable artificial plasmonic nanolasers based on metal–insulator–semiconductor–insulator–metal(MISIM)structure,which demonstrates its ability to compress the mode field volume toλ/*** the pump power increases,the proposed artificial plasmonic nanolaser exhibits 20-nm-wide output ***,we investigate the effects of various cavity parameters on the nanolaser’s output threshold,offering potentials for realizing low-threshold artificial plasmonic ***,we observe a blue shift in the center wavelength of the nanolaser output with thinner gain layer thickness,predominantly attributed to the increased exciton–photon coupling *** work brings inspiration to several areas,including spaser-based interconnects,nano-LEDs,spontaneous emission control,miniaturization of photon condensates,eigenmode engineering of plasmonic nanolasers,and optimal design driven by artificial intelligence(AI).

关键词： surface plasmon polaritons nanolaser ultrafast MISIM

Dual-band dynamic reconfigurable intelligent surface for signal enhancement in millimeter wave

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science China(Technological sciences) 2024年第4期67卷 1133-1138页

作者： YAO HuiMing DU XinRun WANG HengBin GAO Song PANG YaChen ZHENG HaiRong GONG HuiWen LI Yi XU JianChun ZHANG JianHua BI Ke state key laboratory of information photonics and optical communications School of ScienceBeijing University of Posts and TelecommunicationsBeijing 100876China Beijing key laboratory of Intelligent Telecommunications Software and Multimedia Beijing University of Posts and TelecommunicationsBeijing 100876China state key laboratory of Networking and Switching Technology Beijing University of Posts and TelecommunicationsBeijing 100876China

Millimeter wave with large bandwidth,high transmission rate,and low delay is considered a reliable alternative to cope with the spectrum ***,the fast attenuation and narrow beam characteristics make it difficult to achieve long-distance or wide-range ***,a 1-bit dual-band reflective reconfigurable intelligent surface(RIS)for signal enhancement in millimeter wave with 16×16 elements is designed,fabricated,and *** from most existent RIS,dynamic programming is realized at two separate frequency bands by integrating the PIN diodes and field-programmable gate array(FPGA).Particularly,the beam deflection,dual-beam,and multi-beam are created based on the coding theory and convolution operation,proving the effectiveness of wavefront ***,the far-field patterns and signal power with different coding sequences are measured and *** is indicated that the received signal power is 6–7 dB stronger than that without coding,which shows good agreement with the desired *** proposed reconfigurable metasurface exhibits great potential in beam forming,making it a promising candidate for progressive wireless communication applications.

关键词： dual-band millimeter wave reconfigurable intelligent surface signal enhancement