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Versatile photonic molecule switch in multimode microresonators

Light(Science & Applications) 2024年第3期13卷 498-509页

作者： Zihan Tao Bitao Shen Wencan Li Luwen Xing Haoyu Wang Yichen Wu Yuansheng Tao Yan Zhou yandong he Chao Peng Haowen Shu Xingjun Wang State Key Laboratory of Advanced Optical Communications System and Networks School of ElectronicsPeking UniversityBeijing 100871China College of Engineering Peking UniversityBeijing 100871China School of Integrated Circuits Peking University100871 BejingChina Peking University Yangtze Delta Institute of Optoelectronics Nantong 226010China Frontiers Science Center for Nano-optoelectronics Peking UniversityBeijing 100871China Peng Cheng Laboratory Shenzhen 518055China

Harnessing optical supermode interaction to construct artificial photonic molecules has uncovered a series of fundamental optical phenomena analogous to atomic ***,the distinct energy levels and interactions in such two-level systems were provided by coupled *** reconfigurability is limited,as they often require delicate external field stimuli or mechanically altering the geometric *** highly specific approaches also limit potential ***,we propose a versatile on-chip photonic molecule in a multimode microring,utilizing a flexible regulation methodology to dynamically control the existence and interaction strength of spatial *** transition between single/multi-mode states enables the“switched-off/on”functionality of the photonic molecule,supporting wider generalized applications *** particular,“switched-on”state shows flexible and multidimensional mode splitting control in aspects of both coupling strength and phase difference,equivalent to the *** *** effect.“Switched-off”state allows for perfect low-loss single-mode transition(Qi~10 million)under an ultra-compact bend size(FSR~115 GHz)in a foundry-based silicon *** breaks the stereotyped image of the FSR-Q factor trade-off,enabling ultra-wideband and high-resolution millimeter-wave photonic *** demonstration provides a flexible and portable solution for the integrated photonic molecule system,extending its research scope from fundamental physics to real-world applications such as nonlinear optical signal processing and sixth-generation wireless communication.

关键词： switched multimode millimeter

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A low-fabrication-temperature, high-gain chip-scale waveguide amplifier

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Science China(Information Sciences) 2022年第6期65卷 247-255页

作者： Bo WANG Peiqi ZHOU Xingjun WANG yandong he State Key Laboratory of Advanced Optical Communication Systems and Networks Department of ElectronicsSchool of Electronics Engineering and Computer Science Peking University Institute of Microelectronics School of Electronics Engineering and Computer Science Peking University Frontier Science Center for Nano-optoelectronics Peking University Peking University Yangtze Delta Institute of Optoelectronics Peng Cheng Laboratory

The increasing prevalence of integrated on-chip optoelectronic devices has identified serious issues regarding inter-device transmission and coupling losses, highlighting an urgent need for on-chip waveguide amplifiers to compensate for these losses. Compared with other Er-based optical materials, erbium silicate is ideally suited to high-efficiency on-chip amplifiers and lasers because of its extremely high Er3+concentration(1022cm-3). Nevertheless, erbium silicate must be annealed above 1000℃ to crystallize and activate the Er3+, which damages other on-chip optoelectronic components and is not conducive to device ***, we report a low-fabrication-temperature, high-luminescence-efficiency gain material by adding Bi2O3to an erbium-ytterbium silicate mixed film. Our experiments demonstrate that the proposed film crystallizes at 600℃ while the activation of Er3+is also achieved, which is the lowest activation temperature of on-chip waveguide amplifier to our knowledge. This material forms the basis for a new chip-scale waveguide amplifier design, with a theoretical multi-energy-level model of Bi-Er-Yb in the mixed thin films used to analyze its signal enhancement properties. We achieve a peak on-chip gain of 23 dB in a 3.3-mm-long waveguide under the pump and signal powers of 300 mW and 1 μW, respectively. These results highlight the potential of the proposed material for realizing on-chip amplifiers and lasers for large-scale nanophotonic integrated circuits.

关键词： photonic circuit integration low fabrication temperature high gain rare earth material waveguide amplifier

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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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Improved turn-on behavior in a diode-triggered silicon-controlled rectifier for high-speed electrostatic discharge protection

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Science China(Information Sciences) 2019年第6期62卷 79-86页

作者： Lizhong ZHANG Yuan WANG Yize WANG Xing ZHANG yandong he Key Laboratory of Microelectronic Devices and Circuits (MoE) Institute of MicroelectronicsPeking University

A conventional diode-triggered silicon-controlled rectifier(DTSCR) structure with a layout strategy for electrostatic discharge(ESD) protection is presented and confirmed in a 65-nm CMOS *** modified device is featured by a scaled-down trigger-diode string, which shortens its turn-on time using a variable scaling factor. To confirm the parasitic resistance adjustments of the modified DTSCR, transmission line pulsing(TLP)/very fast transmission line pulsing(VF-TLP) tests and simulations are performed on the device. Compared to a conventional DTSCR, this structure exhibits an improved turn-on speed and robustness, which are suitable for I/O protection of ESD events in the nanosecond range, particularly the charged-device model(CDM) event.

关键词： diode triggered silicon controlled rectifier(DTSCR) electrostatic discharge(ESD) transmission line pulsing(TLP) very fast transmission line pulsing(VF-TLP) turn-on behavior

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Insight into multiple-triggering effect in DTSCRs for ESD protection

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Journal of Semiconductors 2017年第7期38卷 93-96页

作者： Lizhong Zhang Yuan Wang Yize Wang yandong he Key Laboratory of Microelectronic Devices and Circuits (MoE) Institute of Microelectronics Peking UniversityBeijing 100871 China

The diode-triggered silicon-controlled rectifier（DTSCR） is widely used for electrostatic discharge（ESD） protection in advanced CMOS process owing to its advantages, such as design simplification, adjustable trigger/holding voltage, low parasitic capacitance. However, the multiple-triggering effect in the typical DTSCR device may cause undesirable larger overall trigger voltage, which results in a reduced ESD safe margin. In previous research, the major cause is attributed to the higher current level required in the intrinsic SCR. The related discussions indicate that it seems to result from the current division rule between the intrinsic and parasitic SCR formed in the triggering process. In this letter, inserting a large space into the trigger diodes is proposed to get a deeper insight into this issue. The triggering current is observed to be regularly reduced along with the increased space, which confirms that the current division is determined by the parasitic resistance distributed between the intrinsic and parasitic SCR paths. The theoretical analysis is well confirmed by device simulation and transmission line pulse（TLP） test results. The reduced overall trigger voltage is achieved in the modified DTSCR structures due to the comprehensive result of the parasitic resistance vs triggering current, which indicates a minimized multipletriggering effect.

关键词： electrostatic discharge(ESD) diode-triggered silicon-controlled rectifier(DTSCR) double snapback transmission line pulse(TLP) test

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Microstructures and micromechanical behaviors of high -entropy alloys investigated by synchrotron X-ray and neutron diffraction techniques: A review

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International Journal of Minerals,Metallurgy and Materials 2024年第6期31卷 1333-1349页

作者： Yubo Huang Ning Xu Huaile Lu Yang Ren Shilei Li yandong Wang Beijing Advanced Innovation Center of Materials Genome Engineering State Key Laboratory for Advanced Metals and MaterialsUniversity of Science and Technology BeijingBeijing 100083China AnSteel Beijing Research Institute Co.Ltd. Beijing 102200China Spallation Neutron Source Science Center Dongguan 523803China Department of Physics City University of Hong KongHong Kong 999077China Institute for Materials Intelligent Technology Liaoning Academy of MaterialsShenyang 110004China

High-entropy alloys(heAs)possess outstanding features such as corrosion resistance,irradiation resistance,and good mechan-ical properties.A few heAs have found applications in the fields of aerospace and *** studies on the deformation mech-anisms of heAs can guide microstructure control and toughness design,which is vital for understanding and studying state-of-the-art structural *** X-ray and neutron diffraction are necessary techniques for materials science research,especially for in situ coupling of physical/chemical fields and for resolving macro/microcrystallographic information on ***,several re-searchers have applied synchrotron X-ray and neutron diffraction methods to study the deformation mechanisms,phase transformations,stress behaviors,and in situ processes of heAs,such as variable-temperature,high-pressure,and hydrogenation *** this review,the principles and development of synchrotron X-ray and neutron diffraction are presented,and their applications in the deformation mechanisms of heAs are *** factors that influence the deformation mechanisms of heAs are also *** review fo-cuses on the microstructures and micromechanical behaviors during tension/compression or creep/fatigue deformation and the application of synchrotron X-ray and neutron diffraction methods to the characterization of dislocations,stacking faults,twins,phases,and intergrain/interphase stress *** on future developments of synchrotron X-ray and neutron diffraction and on research directions on the deformation mechanisms of novel metals are discussed.

关键词： high-entropy alloys microstructures micromechanical behaviors synchrotron X-ray diffraction neutron diffraction

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TibetanGoTinyNet:a lightweight U-Net style network for zero learning of Tibetan Go

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Frontiers of Information Technology & Electronic Engineering 2024年第7期25卷 924-937页

作者： Xiali LI Yanyin ZHANG Licheng WU yandong CheN Junzhi YU Key Laboratory of Ethnic Language Intelligent Analysis and Security Governance Ministry of EducationMinzu University of ChinaBeijing 100081China School of Information Engineering Minzu University of ChinaBeijing 100081China Department of Advanced Manufacturing and Robotics College of EngineeringPeking UniversityBeijing 100871China

The game of Tibetan Go faces the scarcity of expert knowledge and research ***,we study the zero learning model of Tibetan Go under limited computing power resources and propose a novel scaleinvariant U-Net style two-headed output lightweight network *** lightweight convolutional neural networks and capsule structure are applied to the encoder and decoder of TibetanGoTinyNet to reduce computational burden and achieve better feature extraction *** autonomous self-attention mechanisms are integrated into TibetanGoTinyNet to capture the Tibetan Go board’s spatial and global information and select important *** training data are generated entirely from self-play *** achieves 62%–78%winning rate against other four U-Net style models including Res-UNet,Res-UNet Attention,Ghost-UNet,and Ghost *** also achieves 75%winning rate in the ablation experiments on the attention mechanism with embedded positional *** model saves about 33%of the training time with 45%–50%winning rate for different Monte–Carlo tree search(MCTS)simulation counts when migrated from 9×9 to 11×11 *** for our model is available at https://***/paulzyy/TibetanGoTinyNet.

关键词： Zero learning Tibetan Go U-Net Self-attention mechanism Capsule network Monte-Carlo tree search

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A study on vector mediator top-philic dark matter

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Communications in Theoretical Physics 2024年第08期76卷 69-80页

作者： Yanyan Hu yandong Liu Yuanyuan Liu College of Nuclear Science and Technology Beijing Normal University Joint Laboratory of Jinping Ultra-low Radiation Background Measurement of Ministry of Ecology and Environment Jinping Deep Underground Frontier Science and Dark Matter Key Laboratory of Sichuan Province Key Laboratory of Beam Technology of Ministry of Education Beijing Radiation Center

We conducted a study on a simplified dark matter model that introduces a vector-like intermediate particle, facilitating exclusive interactions between dark matter and the top quark in the Standard Model. The analysis focused on the relic density of Dirac-type fermion dark matter and highlighted the complementary role of direct detection in constraining the dark matter model. Notably, in instances when dark matter mass is small, the tree-level two-body annihilation process experiences suppression. In such scenarios, the contributions of the threebody process(■) and the one-loop process(■ → gg) dominate the relic *** regard to direct detection, calculations were performed for the two-loop contribution to the dark-matter–gluon interaction, yielding the corresponding spin-independent scattering cross section.

关键词： dark matter effective field theory new physics

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Process optimization of plasma nitridation SiON for 65 nm node gate dielectrics

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Science China(Information Sciences) 2011年第12期54卷 2693-2699页

作者： he yandong , ZHANG Xing & WANG YangYuan Institute of Microelectronics, Peking University, Beijing 100871, China Institute of Microelectronics Peking University Beijing China

The gate leakage current and reliability concern become more serious due to the aggressive scaling-down of the gate oxide thickness. Developing advanced gate dielectrics process for mass production is essential in China. In this paper, the gate leakage current reduction and reliability optimization for plasma nitridation SiON aimed at 65 nm node CMOS application was explored. A three-step fabrication process based on single wafer tools for plasma nitridation SiON has been demonstrated. The effects of each process condition on the electrical and reliability characteristics of plasma nitridation SiON have been investigated in terms of nitrogen concentration, equivalent oxide thickness(EOT), gate leakage current, mobility, time-dependent dielectric breakdown (TDDB) and negative bias temperature instability (NBTI). The optimized plasma nitrided oxide demonstrated good gate leakage reduction and high carrier mobility without sacrificing the reliability performance. This optimized plasma nitridation process has been implemented into the mass production to meet the throughput and reliability requirement.

关键词： plasma nitridation post-nitridation annealing gate leakage current NBTI TDDB

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Abnormal mechanochemical effect in ultraprecision machining of an additively manufactured precipitation-strengthened high-entropy alloy

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Journal of Materials Science & Technology 2024年第3期170卷 221-237页

作者： Long Xu Yuchao Bai Yunfa Guo Chang Ren Xiaohua Tan yandong Jia Gang Wang Hao Wang Institute of Materials Shanghai UniversityShanghai 200444China Zhejiang Institute of Advanced Materials Shanghai UniversityJiashan 314100China Department of Mechanical Engineering National University of SingaporeSingapore 117575Singapore

Recently,researchers have explored the use of precipitation strengthening and finer microstructures with high-density dislocations in additive manufacturing to produce high-entropy alloys(heAs)with adjustable ***,the inherent surface roughness and lack of machinability research in AMed heAs limit their engineering *** this study,we systematically investigated the microstructural characteristics,mechanical properties,and machinability of Fe_(29.3)Co_(28.7)Ni_(28.6)Al_(6.8)Ti_(6.6)(at.%)heAs with three different structures:single FCC phase cellular(SPC),dual precipitation-strengthened(DPS),and single precipitation-strengthened(SPS).These structures were fabricated by selective laser melting and isothermally annealing at 780 and 940℃.Compared to SPC heA,DPS heA exhibits a significant increase in yield strength and ultimate tensile strength but with a dramatic sacrifice in *** heA exhibits similar mechanical properties to SPC heA due to the pronounced coarsening of L21 *** ultraprecision machining micro-cutting test showed that SPC heA had a significant mechanochem-ical effect,as evidenced by a sharp drop in cutting force for inked workpieces,but not DPS *** abnormal finding was that the negligible reflection of cutting force for SPS heAs suggested a negative mechanochemical effect,even though SPS heA had equally excellent plasticity like SPC *** was found that nanocrystallization-induced strength enhancement and ductility reduction of SPS heA lead to chips’deformation dominated by shear avalanche rather than chip folding of SPC heA,which involves the reduction of surface energy and friction of chips’***,these results and our research findings may guide the machining of AMed precipitation-strengthened heAs and accelerate their engineering ap-plication.

关键词： High-entropy alloy Selective laser melting Precipitation strengthening Machinability Mechanochemical effect

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