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

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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Towards silicon photonic neural networks for artificial intelligence

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Science China(Information Sciences) 2020年第6期63卷 105-118页

作者： Bowen BAI Haowen SHU xingjun wang Weiwen ZOU State Key Laboratory of Advanced Optical Communications System and Networks School of Electronics Engineering and Computer Science Peking University Frontiers Science Center for Nano-optoelectronics Peking University State Key Laboratory of Advanced Optical Communication Systems and Networks Intelligent Microwave Lightwave Integration Innovation Center(iMLic) Department of Electronic Engineering Shanghai Jiao Tong University

Brain-inspired photonic neural networks for artificial intelligence have attracted renewed interest. For many computational tasks, such as image recognition, speech processing and deep learning, photonic neural networks have the potential to increase the computing speed and energy efficiency on the orders of magnitude compared with digital electronics. Silicon Photonics, which combines the advantages of electronics and photonics, brings hope for the large-scale photonic neural network integration. This paper walks through the basic concept of artificial neural networks and focuses on the key devices which construct the silicon photonic neuromorphic systems. We review some recent important progress in silicon photonic neural networks, which include multilayer artificial neural networks and brain-like neuromorphic systems, for artificial intelligence. A prototype of silicon photonic artificial intelligence processor for ultra-fast neural network computing is also proposed. We hope this paper gives a detailed overview and a deeper understanding of this emerging field.

关键词： photonic neural networks artificial intelligence deep learning photonic computing accelerator silicon photonics

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A design method for high fabrication tolerance integrated optical mode multiplexer

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Science China(Information Sciences) 2020年第6期63卷 184-194页

作者： Bitao SHEN Haowen SHU Linjie ZHOU xingjun wang State Key Laboratory on Advanced Optical Communication Systems and Networks Department of ElectronicsSchool of Electronics Engineering and Computer Science Peking University State Key Laboratory of Advanced Optical Communication Systems and Networks Department of Electronic Engineering Shanghai Jiao Tong University Nano-optoelectronics Frontier Center of Ministry of Education Peking University

The tapered asymmetric directional coupler has the potential to realize high fabrication tolerance and high transmission efficiency on-chip mode multiplexer. However, the geometry parameter selection of tapered structure remains empirical. In this paper, we propose a design method for the tapered structure based on genetic algorithm. Combined with the adjusted coupling equations and interpolation method, lowtime-cost optimization can be realized. Three mode multiplexers(TE0&TE1, TE0&TE2 and TE0&TE5)are designed by our method. According to simulation results, the insertion loss of the designed devices is lower than 1.8 dB and the crosstalk is lower than-15 dB when the fabrication error is within required range(±10 nm for TE0&TE2 and TE0&TE5, and ±20 nm for TE0&TE1) in the bandwidth of 1.5–1.6 μm. In addition, the entire optimization process takes only 2 h for each device, which is around the time cost of a single 3 D simulation.

关键词： mode multiplexer directional coupler taper structure coupled-mode theory genetic algorithm

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Towards an intelligent photonic system

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Science China(Information Sciences) 2020年第6期63卷 80-96页

作者： Weiwen ZOU Bowen MA Shaofu XU Xiuting ZOU xingjun wang State Key Laboratory of Advanced Optical Communication Systems and Networks Intelligent Microwave Lightwave Integration Innovation Center (iMLic) Department of Electronic EngineeringShanghai Jiao Tong University State Key Laboratory of Advanced Optical Communication Systems and Networks School of Electronics Engineering and Computer Science Peking University

The emerging intelligence technologies represented by deep learning have broadened their applications to various fields. Beyond the conventional electronics-based processing systems, the convergence of photonics and artificial intelligence(AI) technology enhances the performance and learning ability of AI. In this review, we propose the concept of an intelligent photonic system(IPS), illustrating it as a developing architecture with three different versions. For each version of IPS, we review several representative *** we discuss the challenges towards an IPS and provide some prospects for the future development.

关键词： intelligent photonic system deep learning artificial intelligence optical neural network neuromorphic photonics

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Spontaneous emission rate and optical amplification of Er3+ in double slot waveguide

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Science China(Physics,Mechanics & Astronomy) 2015年第12期58卷 166-172页

作者： wang xingjun JIANG LingJun GUO RuiMin YE Rui ZHOU ZhiPing State Key Laboratory of Advanced Optical Communication Systems and Networks School of Electronics Engineering and Computer SciencePeking University Division of Biological Energy and Environmental Measurement National Institute of Metrology

The spontaneous emission(SE) of Er3+ embedded in a double slot dielectric structure was studied by a quantum-electrodynamical formalism. The study shows that the slot width and the position of Er3+ in slot structure have a significant effect on the SE. The double slot waveguides were fabricated by embedding two low-index Er/Yb silicate material layers into high-index silicon. The radiative efficiency of Er3+ in the double slot waveguides is found to be higher than that of the single slot waveguide, which is consistent with the theory simulation. The 0.67 d B signal enhancement at 1.53 ?m in a 4.6-mm-long slot waveguide was observed pumped by 1476 nm laser. These results show the relevance of our model to study the SE processes in multilayer structures and are important for future realization of silicon-compatible active optical devices.

关键词： slot waveguide spontaneous emission rate quantum efficiency

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High performance architecture for unified forward and inverse transform of HEVC

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The Journal of China Universities of Posts and Telecommunications 2017年第3期24卷 16-23页

作者： Jiang Lin wang xingjun Wu Xin Deng Junyong Huang Xingjie School of Electronic Engineering Xi'an University of Posts and Telecommunications College of Computer and Information Science Northeastern University

High efficiency video coding （HEVC） transform algorithm for residual coding uses 2-dimensional （2D） 4 × 4 transforms with higher precision than H.264＇s 4 ×4 transforms, resulting in increased hardware complexity. In this paper, we present a shared architecture that can compute the 4 ~4 forward discrete cosine transform （DCT） and inverse discrete cosine transform （IDCT） of HEVC using a new mapping scheme in the video processor array structure. The architecture is implemented with only adders and shills to an area-efficient design. The proposed architecture is synthesized using ISE 14.7 and implemented using the BEE4 platform with the Virtex-6 FF1759 LX550T field programmable gate array （FPGA）. The result shows that the video processor array structure achieves a maximum operation frequency of 165.2 MHz. The architecture and its implementation are presented in this paper to demonstrate its programmable and high performance.

关键词： HEVC forward and inverse transform reconfigurable architecture video processor array structure

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A real-time tunable arbitrary power ratios graphene based power divider

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Science China(Information Sciences) 2018年第8期61卷 104-106页

作者： Haowen SHU Yuansheng TAO Ming JIN xingjun wang Zhiping ZHOU State Key Laboratory of Advanced Optical Communications System and Networks School of Electronics Engineering and Computer Science Peking University

Dear editor,Recently,photonics integrated circuits have attracted extensive consideration for its realization of large-scale integration of various devices and functionalities on a single chip[1].As a fundamental buil... 详细信息

关键词： Figure A real-time tunable arbitrary power ratios graphene based power divider length GOS

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Facile Route to Synthesize Pore Expanded Platelet SBA-15 for Enhanced Amidoxime-Functionalization and Efficient Extraction of U(Ⅵ) from Aqueous Solution

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Journal of Ocean University of China 2020年第5期19卷 1103-1115页

作者： JI Guojia wang xingjun ZHU Guiru SONG Chenghao YUAN Junsheng GAO Congjie Key Laboratory of Marine Chemistry Theory and Technology Ministry of EducationCollege of Chemistry and Chemical EngineeringOcean University of ChinaQingdao 266100China College of Chemical Engineering Hebei Normal University of Science and TechnologyQinhuangdao 066600China School of Chemical Engineering Hebei University of TechnologyTianjin 300130China

Short channel platelet SBA-15 mesoporous material is one of the effective adsorbent for the recovery of U(Ⅵ) from aqueous solution. Nevertheless, the defect is that the mesoporous size limits the total stripping of attached U(Ⅵ) in recycling use and the increasing densities of organic groups after functionalization. Thus, a simple and controllable method was adopted to prepare SBA-15-type material with expanded pore channel by adding trimethylbenzene in synthesis procedure. The structure, morphology and functional groups were characterized by scanning electron microscope, powder X-ray diffraction, thermogravimetric analysis, transmission electron microscope, FTIR and N_2 adsorption-desorption isotherm analysis. Furthermore, the adsorption behavior of obtained product was test under various factors such as initial concentration, pH, elution rate and contact time. The pore expanded platelet SBA-15 exhibited higher U(Ⅵ) adsorption capacity, higher elution rate, and more bearing of amidoxime groups. Due to the higher amidoxime groups, the adsorption capacity of U(Ⅵ) on the amidoxime functionalized pore-expanded SBA-15 was 674 mg-Ug^-1. The results show that the simple and controllable pore-expanded method is an effective strategy to enhance the elution effect and increase grafting amount of organic groups on the mesoporous materials.

关键词： platelet SBA-15 pore expanded amidoxime-functionalization U(Ⅵ)adsorption

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Enhanced near-zero-CO2-emission chemicals-oriented oil production from coal with inherent CO2 recycling: Part I—PRB coal fast pyrolysis coupled with CO2/CH4 reforming

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International Journal of Coal Science & Technology 2020年第3期7卷 433-443页

作者： xingjun wang Bin Wei Xin Huang Maohong Fan Yonggang wang Xueli Chen School of Resources and Environment Engineering East China University of Science and TechnologyShanghai200237China School of Chemical and Environmental Engineering China University of Mining and TechnologyBeijing100080China Departments of Petroleum and Chemical Engineering University of WyomingLaramieWY82071USA School of Energy Resources University of WyomingLaramieWY82071USA

In this study,the Powder River Basin(PRB)coal fast pyrolysis was conducted at 700°C in the atmosphere of syngas produced by CH4-CO2 reforming in two different patterns,including the double reactors pattern(the first reactor is for syngas production and the second is for coal pyrolysis)and double layers pattern(catalyst was at upper layer and coal was at lower layer).Besides,pure gases atmosphere including N2,H2,CO,H2-CO were also tested to investigate the mechanism of the coal pyrolysis under different *** pyrolysis products including gas,liquid and char were characterized,the result showed that,compared with the inert atmosphere,the tar yield is improved with the reducing atmospheres,as well as the tar *** hydrogen partial pressure is the key point for that *** the atmosphere of H2,the tar yield was increased by 31.3%and the contained BTX(benzene,toluene and xylene)and naphthalene were increased by 27.1%and 133.4%.The double reactors pattern also performed outstandingly,with 25.4%increment of tar yield and 25.0%and 79.4%for the BTX and *** double layers pattern is not effective enough due to the low temperature(700°C)in which the Ni-based catalyst was not fully activated.

关键词： Coal pyrolysis Coal tar CO2/CH4 reforming BTX

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In-situ study on structure evolution and gasification reactivity of biomass char with K and Ca catalysts at carbon dioxide atmosphere

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Carbon Resources Conversion 2023年第1期6卷 27-33页

作者： xingjun wang Qian Chen Huaili Zhu Xueli Chen Guangsuo Yu School of Resources and Environmental Engineering East China University of Science and TechnologyShanghai 200237China Shanghai Engineering Research Center of Coal Gasification Shanghai 200237China

The structural evolution and gasification reactivity of biochar prepared from the pyrolysis of wheat straw were investigated by in-situ Raman spectroscopy and thermogravimetric *** Raman spectra consisted of a combination of four Lorentzian bands(D1,D2,D4,G)and one Gaussian band(D3)in the first-order *** experimental results showed that the addition of catalysts or the presence of ash could improve the CO_(2) gasification reactivity of biochar and result in a larger ID1/IG ratio and a lower IG/IALL ratio,meaning that the carbon structure was less ordered,and there were also more active sites such as amorphous carbon and cross-linked structures;Ca-based catalysts and K-based catalysts changed the evolution of biochar structure in a different way in CO_(2) atmosphere,the ID3/ID1 of Ca-based biochar was close to the value of non-catalyst biochar and decreased slowly,indicating that the Ca-based catalysts can stabilize the aromatic rings,while the IG/IALL of K-based biochar decreases significantly and the ID3/ID1 increased significantly,indicating the increase of carbon structure defects and the cracking of large aromatic rings in bio-char into small ones;a scheme of K and Ca reaction with biochar in CO_(2) gasification process was proposed.

关键词： In-situ Raman spectroscopy K and Ca catalysts Gasification reactivity Structure evolution Biomass char

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