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Channel characterization at 12. GHz for future indoor communication systems

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chinese Physics B 2013年第5期22卷 650-656页

作者：陈镇曹俊诚 key laboratory of {2. solid-state technology Shanghai Institute of Microsystem and Information TechnologyChinese Academy of Sciences

We present a simulation on the spatial and temporal characteristics of the indoor propagation channel at 12. GHz. The simulation, applied to a dynamic scenario with randomly placed objects and moving people in a room, is based on a three-dimensional ray-tracing method. Propagation and reflection mechanisms of electromagnetic waves are discussed in the channel model. The received power in a 0.95-m-height plane is obtained. Comparison between walls and ceiling covered with dielectric mirrors and those with three common wall and ceiling materials are presented. The result shows that the holistic received power level with dielectric mirrors is about 10 dB higher than with other materials.

关键词： sub-terahertz communication channel models ray tracing electromagnetic propagation

Performance analysis of LDPC codes on OOK terahertz wireless channels

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chinese Physics B 2016年第2期25卷 553-557页

作者：刘纯王长曹俊诚 key laboratory of {2. solid-state technology Shanghai Institute of Microsystem and Information TechnologyChinese Academy of Science

Atmospheric absorption, scattering, and scintillation are the major causes to deteriorate the transmission quality of terahertz（THz） wireless communications. An error control coding scheme based on low density parity check（LDPC） codes with soft decision decoding algorithm is proposed to improve the bit-error-rate（BER） performance of an on-off keying（OOK） modulated THz signal through atmospheric channel. The THz wave propagation characteristics and channel model in atmosphere is set up. Numerical simulations validate the great performance of LDPC codes against the atmospheric fading and demonstrate the huge potential in future ultra-high speed beyond Gbps THz communications.

关键词： terahertz wireless channels low density parity check codes atmospheric turbulence gamma-gamma models

Suppressed Antiferromagnetism and Superconductivity in As-deficient Iron-based Superconductor of SrFe_(1.8)Co_(0.2.As_x

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稀有金属材料与工程 2011年第S3期40卷 358-361页

作者： Liu Zhiyong1, Lu Yuming1, Liu Jinlei1, Qu Chunqing1,2.3, Chen Changzhao1, Cai Chuanbing1, Huang Fuqiang3, Xie Xiaoming2.1 shanghai University, shanghai 2.0444, {2. 2.state key laboratory of Functional Materials for Informatics,shanghai Institute of microsystem and information technology,chinese academy of sciences,shanghai 2.0050, {2. 3 shanghai Institute of Ceramics, chinese academy of sciences, shanghai 2.0050, {2. shanghai Univ Res Ctr Superconductors & Appl Technol Shanghai 200444 Peoples R China chinese Acad Sci Shanghai Inst Microsyst & Informat Technol State Key Lab Funct Mat Informat Shanghai 200050 Peoples R China chinese Acad Sci Shanghai Inst Ceram Shanghai 200050 Peoples R China

Iron-based superconductors namely Sr(Fe1.8Co0.2.As1.8 (FeAs1.8) and Sr(Fe1.8Co0.2.As1.85 (FeAs1.85) with As deficiency are prepared by solid-state reaction. X-ray diffraction reveals that the polycrystalline phase forms in the studied samples, identical to typical SrFe2.s2.(12.) matrix. Resistive and magnetic measurements show that the superconducting transition temperatures (Tc) are about 19 K for both FeAs1.8 and FeAs1.85. Compared with the performances of typical iron-based 12. superconductors arising from Co doping, the present samples show the suppressed superconductivity. Moreover, the antiferromagnetic (AFM) phase correlated with spin-density-wave (SDW) is reduced as well. The AFM transition temperature decreases to 12. K for FeAs1.85, while such a phase transition is absent at all for FeAs1.8, one sample with less As, implying that the existence of SDW and antiferromagnetism is more sensitive to As content.

关键词： antiferromagnetism superconductivity iron-based superconductors

Impact of Al addition on the formation of Ni germanosilicide layers under different temperature annealing

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chinese Physics B 2017年第9期26卷 509-514页

作者：孟骁然平云霞俞文杰薛忠营魏星张苗狄增峰张波赵清太 shanghai University of Engineering Science Shanghai 201600China state key {2. of Functional Material for Informatics Shanghai Institute of Microsystem and Information TechnologyChinese Academy of SciencesShanghai 200050China Peter Grunberg Institute 9(PGI 9-IT) and JARA-Fundamentals of Future Information TechnologyForschungszentrum JuelichJuelich 52425Germany

solid reactions between Ni and relaxed Si0.7Ge0.3 substrate were systematically investigated with different Al interlayer thicknesses. The morphology, composition, and micro-structure of the Ni germanosilicide layers were analyzed with different annealing temperatures in the appearance of Al. The germanosilicide layers were characterized by Rutherford backscattering spectrometry, cross-section transmission electron microscopy, scan transmission electron microscopy, and secondary ion mass spectroscopy. It was shown that the incorporation of Al improved the surface and interface morphology of the germanosilicide layers, enhanced the thermal stabilities, and retarded the Ni-rich germanosilicide phase to mono germanosilicide phase. With increasing annealing temperature, Al atoms distributed from the Ni/Si0.7Ge0.3 interface to the total layer of Ni2.i0.7Ge0.3, and finally accumulated at the surface of NiSi0.7Ge0.3. We found that under the assistance of Al atoms, the best quality Ni germanosilicide layer was achieved by annealing at 700？C in the case of 3 nm Al.

关键词： germanosilicide Al Ni

Electron dynamics of active mode-locking terahertz quantum cascade laser

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chinese Physics B 2020年第12期29卷 438-441页

作者： Qiushi Hou Chang Wang juncheng cao key laboratory of {2. solid-state technology Shanghai Institute of Microsystem and Information TechnologyChinese Academy of SciencesShanghai 200050China Center of Materials Science and Optoelectronics Engineering University of Chinese Academy of SciencesBeijing 100049China

The pulse generation from active mode-locking terahertz quantum cascade laser is studied by Maxwell-Bloch *** is shown that longer dephasing time will lead to multiple pulses generation from the *** dependence of output field on modulation length and radio-frequency parameters is *** order to achieve short pulse generation,the DC bias should close to threshold value and modulation length should be shorter than 0.2.6 *** output pulse is unstable and the envelope shows many oscillations in the presence of spatial hole burning,resulting destabilization of mode-locking.

关键词： terahertz(THz) quantum cascade lasers(QCLs) mode-locking spatial hole burning(SHB)

Ultrafast optical modulation of the fluorescence from a single-photon emitter in silicon carbide

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Photonics Research 2024年第5期12卷 941-946页

作者： MENGTING HE YUJING cao JUNJIE LIN ZHIPING JU BOTAO WU E WU state key {2. of Precision Spectroscopy East China Normal UniversityShanghai 200241China Photon technology(Zhejiang)Co. Ltd.Jiaxing 314100China National key laboratory of Materials for Integrated Circuits Shanghai Institute of Microsystem and Information TechnologyChinese Academy of SciencesShanghai 200000China Department of Physics and shanghai key {2. for Magnetic Resonance East China Normal UniversityShanghai 200241China Chongqing key laboratory of Precision Optics Chongqing Institute of East China Normal UniversityChongqing 401120China Collaborative Innovation Center of Extreme Optics Shanxi UniversityTaiyuan 030006China

The quest for the room-temperature optical transistor based on nonlinearities in single atoms or molecules is attracting a lot of *** this work,a single-photon emitter in cubic silicon carbide is verified that can operate as an optical switch at room temperature under pulsed green laser illumination with a near-infrared pulsed laser as the control *** demonstrated an ultrafast and reversible optical modulation with a high photoluminescence intensity suppression ratio up to 97.9%and a response time as short as 2.7.9±5.7 *** current development provides insights for high-precision and ultrafast optical switches,with possibilities for integration with emerging electronic installations to realize more intelligent photoelectric integrated devices.

关键词： emitter carbide photon

4.3 THz quantum-well photodetectors with high detection sensitivity

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chinese Physics B 2018年第3期27卷 201-204页

作者： Zhenzhen Zhang Zhanglong FU Xuguang Guo juncheng cao key laboratory of {2. solid-state technology Shanghai Institute of Microsystem and Information TechnologyChinese Academy of SciencesShanghai 200050China Ministry of Education and shanghai key {2. of Modern Optical System and shanghai terahertz Research Center.University of shanghai for Science and technology Shanghai 200093China University of chinese academy of sciences Beijing 100049China

We demonstrate a high performance GaAs/AlGaAs-based quantum-well photodetector(QWP)device with a peak response frequency of 4.3 *** negative differential resistance(NDR)phenomenon is found in the dark currentvoltage(I-V)curve in the current sweeping measurement mode,from which the breakdown voltage is *** photocurrent spectra and blackbody current responsivities at different voltages are *** on the experimental data,the peak responsivity of 0.3 A/W(at 0.15 V,8 K)is derived,and the detection sensitivity is higher than 10^(11)Jones,which is in the similar level as that of the commercialized liquid-helium-cooled silicon *** attribute the high detection performance of the device to the small ohmic contact resistance of-2.and the big breakdown bias.

关键词： terahertz quantum-well photodetector negative differential resistance detection sensitivity pho-tocurrent spectra

Symmetry-broken silicon disk array as an efficient terahertz switch working with ultra-low optical pump power

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chinese Physics B 2020年第8期29卷 72-77页

作者： Zhanghua Han Hui Jiang Zhiyong Tan juncheng cao Yangjian Cai Shandong Provincial key laboratory of Optics and Photonic Devices School of Physics and ElectronicsShandong Normal UniversityJinan 250358China key laboratory of {2. solid-state technology Shanghai Institute of Microsystems and Information TechnologyChinese Academy of SciencesShanghai 200050China Center of Materials Science and Optoelectronics Engineering University of Chinese Academy of SciencesBeijing 100049China

The advancement of terahertz technology in recent years and its applications in various fields lead to an urgent need for functional terahertz components,among which a terahertz switch is one example of the most importance because it provides an effective interface between terahertz signals and information in another physical *** date many types of terahertz switches have been investigated mainly in the form of metamaterials made from metallic structures and optically-active ***,these reported terahertz switches usually suffer from an inferior performance,e.g.,requiring a high pump laser power density due to a low quality factor of the metallic metamaterial *** this paper,we report and numerically investigate a symmetry-broken silicon disk based terahertz resonator array which exhibits one resonance with ultrahigh quality factor for normal incidence of the terahertz *** resonance,which can never be excited for regular circular Si disks,can help to realize a superior terahertz switch with which only an ultra-low optical pump power density is required to modify the free carrier concentration in Si and its refractive index in the terahertz *** findings demonstrate that to realize a high terahertz transmittance change from 0 to above 50%,the required optical pump power density is more than 3 orders of magnitude smaller than that required for a split-ring resonator(SRR)based terahertz switch reported in the literature.

关键词： silicon disk symmetry-broken terahertz switch photocarrier bound state in continuum

terahertz Direct Modulation Techniques for High-speed Communication Systems

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china Communications 2021年第5期18卷 221-244页

作者： Tianchi Zhou Yaxin Zhang Bo Zhang Hongxin Zeng Zhiyong Tan Xilin Zhang Lan Wang Zhi Chen juncheng cao Kaijun Song Ziqiang Yang University of Electronic Science and technology of china ChengduChina Yangtze Delta Region Institute(Huzhou) University of Electronic Science and Technology of ChinaHuzhou 313001China key laboratory of {2. solid state technology Shanghai Institute of Microsystem and Information TechnologyChinese Academy of Sciences865 Changning RoadShanghai 200050China Center of Materials Science and Optoelectronics Engineering University of Chinese Academy of SciencesBeijing 100049China

terahertz communication technology can provide abundant frequency resources,strong confidentiality,antijamming capability,communication tracking capability and the ability to achieve highspeed data transmissions and can serve as an important technical method for high-speed communications in the *** these terahertz communication technologies,terahertz direct modulation technology is a key means to achieve low system complexity and power *** this paper,a review and outlook of terahertz direct modulation technology are proposed from the aspects of high-electron-mobilitytransistor-based terahertz direct modulation,parallelswitch terahertz direct modulation,diode-based terahertz direct modulation,quantum cascade laser-based terahertz direct modulation and new-material-based terahertz direct *** hope through this paper that more readers can gain knowledge about the development and challenges of terahertz direct modulation technology for high-speed communication systems,thus promoting the development of high-speed terahertz communication technology based on direct modulation.

关键词： THz communication THz direct modulation HEMT switches diode QCL new-material