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2021 Asia communications and Photonics Conference, ACP 2021

作者： Tang, Mengxue Zhao, Yunhe Wang, Wei Yang, Yongsheng He, Zuyuan Institute of Logistics Science and Engineering Shanghai Maritime University Shanghai201306 China State Key Laboratory of Advanced Optical Communication Systems and Networks Shanghai Jiao Tong University Shanghai200240 China

We proposed a refractive index (RI) sensor based on arc-discharged long-period fiber gratings in capillary. Sensing performance of the gratings have been investigated experimentally. The proposed RI sensor is insensit... 详细信息

ISBN: (纸本)9781957171005

关键词： Refractive index

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Topological Unidirectional Guided Resonances Emerged from Interband Coupling

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Physical Review Letters 2023年第5期130卷 056401-056401页

作者： Xuefan Yin Takuya Inoue Chao Peng Susumu Noda Department of Electronic Science and Engineering Kyoto University Kyoto-Daigaku-Katsura Nishikyo-ku Kyoto 615-8510 Japan State Key Laboratory of Advanced Optical Communication Systems and Networks School of Electronics and Frontiers Science Center for Nano-optoelectronics Peking University Beijing 100871 China Peng Cheng Laboratory Shenzhen 518055 China

Unidirectional guided resonances (UGRs) are optical modes in photonic crystal slabs that radiate toward one side without the need for mirrors on the other. In this Letter, we report a mechanism to realize UGRs by tuning the interband coupling effect originating from up-down symmetry breaking. We theoretically find that UGRs that reside along high-symmetric lines correspond to phase singularities of far-field radiation, depicted by phase winding numbers as a type of topological indices. We investigate the phase dislocation lines in three-dimensional parameter space and elaborate on the interplay between UGRs and non-Hermitian degeneracies accordingly. Our findings reveal the topological nature of UGRs about their generation, evolution, and annihilation in general parameter spaces, thus paving the way to new possibilities of light manipulation.

关键词： Electric polarization Phononic crystals Photonics Topological effects in photonic systems Polarization Band structure methods

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Holographic-Pattern Based Multi-User Beam Training in RHS-Aided Hybrid Near-Field and Far-Field communications

arXiv

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arXiv 2024年

作者： Zhang, Shupei Di, Boya Kaushik, Aryan Eldar, Yonina C. State Key Laboratory of Advanced Optical Communication Systems and Networks School of Electronics Peking University Beijing China The Department of Computing & Mathematics Manchester Metropolitan University United Kingdom The Faculty of Mathematics and Computer Science Weizmann Institute of Science Rehovot7610001 Israel

Reconfigurable holographic surfaces (RHSs) have been suggested as an energy-efficient solution for extremely large-scale arrays. By controlling the amplitude of RHS elements, high-gain directional holographic patterns can be achieved. However, the complexity of acquiring real-time channel state information (CSI) for beamforming is exceedingly high, particularly in large-scale RHS-assisted communications, where users may distribute in the near-field region of RHS. This paper proposes a one-shot multi-user beam training scheme in large-scale RHS-assisted systems applicable to both near and far fields. The proposed beam training scheme comprises two phases: angle search and distance search, both conducted simultaneously for all users. For the angle search, an RHS angular codebook is designed based on holographic principles so that each codeword covers multiple angles in both near-field and far-field regions, enabling simultaneous angular search for all users. For the distance search, we construct the distance-adaptive codewords covering all candidate angles of users in a real-time way by leveraging the additivity of holographic patterns, which is different from the traditional phase array case. Simulation results demonstrate that the proposed scheme achieves higher system throughput compared to traditional beam training schemes. The beam training accuracy approaches the upper bound of exhaustive search at a significantly reduced overhead. Copyright © 2024, The Authors. All rights reserved.

关键词： Beamforming

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Compact optical Frequency Standard Based on 87Rb D1 Line

Compact Optical Frequency Standard Based on 87Rb D1 Line

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European Frequency and Time Forum (EFTF)

作者： Jingming Chen Jie Miao Qiaohui Yang Tianyu Liu Zhendong Chen Duo Pan Jiqing Lian Jingbiao Chen State Key Laboratory of Advanced Optical Communication Systems and Networks School of Electronics Peking University Beijing China Science and Technology on Vacuum Technology and Physics Laboratory Lanzhou Institute of Physics Lanzhou China School of Mechano-Electronic Engineering Xidian University Xi'an China Hefei National Laboratory Hefei China

ISBN: (数字)9798350354270

ISBN: (纸本)9798350354287

In this paper, we investigate the modulation transfer spectroscopy (MTS) of 87Rb D1 line under noncycling transitions. The line shape of the MTS signal was determined, and the system's long-term stability was measured. Results showed that the system consistently performed at a short-term and long-term stability of E-14 level estimated from the residual error signal, indicating high performance of the compact optical frequency standard.

关键词： Laser theory Time-frequency analysis Spectroscopy Shape Atomic beams Shape measurement Laser stability Adaptive optics Standards Physics

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Multi-frequency terahertz Smith-Purcell radiation via momentum-mismatch-driven quasi-bound states in the continuum

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Photonics Research 2025年第3期13卷 593-603页

作者： ZI-WEN ZHANG JUAN-FENG ZHU FENG-YUAN HAN XIAO LIN CHAO-HAI DU Center for Carbon-based Electronics School of ElectronicsPeking UniversityBeijing 100871China State Key Laboratory of Advanced Optical Communication Systems and Networks School of ElectronicsPeking UniversityBeijing 100871China Science Mathematicsand Technology(SMT)Singapore University of Technology and DesignSingapore 487372Singapore Interdisciplinary Center for Quantum Information State Key Laboratory of Extreme Photonics and InstrumentationZJU-Hangzhou Global Scientific and Technological Innovation CenterCollege of Information Science&Electronic EngineeringZhejiang UniversityHangzhou 310027China International Joint Innovation Center The Electromagnetics Academy at Zhejiang UniversityZhejiang UniversityHaining 314400China

Bound states in the continuum(BICs)have gained considerable attention for their ability to strengthen light-matter interactions,enabling applications in lasing,sensing,and *** properties also show great promise for intensifying free-electron ***,researchers realized momentum-mismatch-driven quasi-BICs in compound grating *** category of quasi-BICs exhibits high Q factors over a broad frequency *** this paper,we explore the possibility of achieving multi-frequency terahertz Smith-Purcell radiation empowered by momentum-mismatch-driven quasi-BICs in silicon compound grating *** leveraging the low-loss properties of silicon in the terahertz range,quasi-BICs are achieved through guided-mode resonance,delivering exceptionally high Q factors over a broad frequency *** broadband nature of these quasi-BICs enables efficient energy extraction from electron beams across varying voltages,while their multimode characteristics support simultaneous interactions with multiple modes,further boosting radiation *** findings demonstrate significant enhancement of free-electron radiation at multiple frequencies,addressing the limitations of narrowband methods and high-loss metallic *** integrating broadband performance with the advantages of low-loss dielectric platforms,this work advances the development of compact,tunable terahertz free-electron radiation sources and provides valuable insights into optimizing quasi-BIC systems for practical applications.

关键词： multi frequency momentum mismatch compound grating waveguides terahertz smith purcell radiation compound grating waveguidesthis bound states continuum bics silicon

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Influence of thermal effects on atomic Bloch oscillation

arXiv

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arXiv 2024年

作者： Yin, Guoling Lai, Chi-Kin Chang, Nana Liang, Yi Mao, Dekai Zhou, Xiaoji State Key Laboratory of Quantum Optics and Quantum Optics Devices Institute of Opto-Electronics Shanxi University Taiyuan030006 China State Key Laboratory of Advanced Optical Communication Systems and Networks School of Electronics Peking University Beijing100871 China Institute of Carbon-based Thin Film Electronics Peking University Taiyuan Shanxi030012 China

Advancements in the experimental toolbox of cold atoms have enabled the meticulous control of atomic Bloch oscillation within optical lattices, thereby enhancing the capabilities of gravity interferometers. This work delves into the impact of thermal effects on Bloch oscillation in 1D accelerated optical lattices aligned with gravity by varying the system’s initial temperature. Through the application of Raman cooling, we effectively reduce the longitudinal thermal effect, stabilizing the longitudinal coherence length over the timescale of its lifetime. The atomic losses over multiple Bloch oscillation is measured, which are primarily attributed to transverse excitation. Furthermore, we identify two distinct inverse scaling behaviors in the oscillation lifetime scaled by the corresponding density with respect to temperatures, implying diverse equilibrium processes within or outside the Bose-Einstein condensate regime. The competition between the system’s coherence and atomic density leads to a relatively smooth variation in the actual lifetime versus temperature. Our findings provide valuable insights into the interaction between thermal effects and Bloch oscillation, offering avenues for the refinement of quantum measurement technologies. © 2024, CC BY.

关键词： optical lattices

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The influence of proton radiation on the performance of silicon Mach-Zehnder modulator

The influence of proton radiation on the performance of sili...

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2021 Asia communications and Photonics Conference, ACP 2021

作者： Han, Changhao Hu, Zhaoyi Tao, Yuansheng Fu, Engang Wang, Xingjun State Key Laboratory of Advanced Optical Communications System and Networks Department of Electronics School of Electronics Engineering and Computer Science Peking University Beijing100871 China State Key Laboratory of Nuclear Physics and Technology School of Physics Peking University Beijing100871 China

The influence of proton radiation on silicon Mach-Zehnder modulator performance was studied for space environment. The modulator was sensitive to proton radiation while still demonstrated a certain working ability aft... 详细信息

ISBN: (纸本)9781957171005

关键词： Silicon

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Quantum noise of dark pulse microcombs

Quantum noise of dark pulse microcombs

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CLEO: QELS_Fundamental Science, QELS 2022

作者： Lao, Chenghao Jin, Xing Chang, Lin Xie, Weiqiang Shu, Haowen Wang, Xingjun Bowers, John E. Yang, Qi-Fan State Key Laboratory for Artificial Microstructure and Mesoscopic Physics Frontiers Science Center for Nano-Optoelectronics School of Physics Peking University Beijing100871 China Department of Electrical and Computer Engineering University of California Santa BarbaraCA93106 United States State Key Laboratory of Advanced Optical Communications System and Networks Department of Electronics School of Electronics Engineering and Computer Science Peking University Beijing100871 China

We investigate the fundamental timing jitter of dark pulse microcombs generated in an AlGaAs microresonator, where the quantum-limited frequency noise of the 91-GHz repetition rate is measured to be 0.5 Hz2/Hz. ©... 详细信息

ISBN: (纸本)9781557528209

关键词： Aluminum gallium arsenide

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Velocity-comb modulation transfer spectroscopy

arXiv

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arXiv 2025年

作者： Guan, Xiaolei Xiao, Zheng Liu, Zijie Wang, Zhiyang Zhang, Jia Gao, Xun Chang, Pengyuan Shi, Tiantian Chen, Jingbiao State Key Laboratory of Advanced Optical Communication Systems and Networks Institute of Quantum Electronics School of Electronics Peking University Beijing100871 China Institute of Quantum Information and Technology Nanjing University of Posts and Telecommunications Nanjing210003 China National Key Laboratory of Advanced Micro and Nano Manufacture Technology School of Integrated Circuits Peking University Beijing100871 China Hefei National Laboratory Hefei230088 China

Sub-Doppler laser spectroscopy is a crucial technique for laser frequency stabilization, playing a significant role in atomic physics, precision measurement, and quantum communication. However, recent efforts to improve frequency stability appear to have reached a bottleneck, as they primarily focus on external technical approaches while neglecting the fundamental issue of low atomic utilization ( Copyright © 2025, The Authors. All rights reserved.

关键词： Frequency stability

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Proton radiation effects on high-speed silicon Mach-Zehnder modulators for space application

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Science China(Information Sciences) 2022年第12期65卷 301-312页

作者： Changhao HAN Zhaoyi HU Yuansheng TAO Engang FU Yandong HE Fenghe YANG Jun QIN Xingjun WANG State Key Laboratory of Advanced Optical Communication Systems and Networks School of Electronics Peking University State Key Laboratory of Nuclear Physics and Technology School of Physics Peking University Institute of Microelectronics School of Integrated Circuits Peking University Peking University Yangtze Delta Institute of Optoelectronics Frontier Science Center for Nano-optoelectronics Peking University Peng Cheng Laboratory

In this paper, performance degradation effects on high-speed silicon Mach-Zehnder modulators under proton radiation were investigated for future space environment applications. The test devices were exposed to 3-MeV protons of three fluence levels(5×1013, 2×1014, and 5×1015ions/cm2), which is comparable to the radiation amount for operating in a harsh space environment after several decades. The performance of the silicon modulator after radiation was characterized in terms of modulation efficiency and eye *** results illustrate that the modulation efficiency is significantly reduced after proton radiation and shows an obvious decrease with increasing radiation fluence. The extinction ratios of the on-off keying（OOK） eye diagram are obviously dropped with increasing radiation fluence and correspond well to modulation efficiency degradation. Furthermore, three representative states for data transmission are demonstrated under three fluences, from still working to the critical state and eventually complete fail. Displacement damage and ionization damage are the two major mechanisms during proton radiation, which lead to the bulk defects and accumulating defect charges and cause performance degradation of silicon Mach-Zehnder modulators.

关键词： silicon Mach-Zehnder modulator proton radiation space application silicon photonics optical communication

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