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Scalable parallel ultrafast optical random bit generation based on a single chaotic microcomb

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Light(Science & Applications) 2024年第4期13卷 637-644页

作者： Pu Li Qizhi Li Wenye Tang Weiqiang Wang Wenfu Zhang Brent ELittle Sai Tek Chu kAlan shore Yuwen Qin Yuncai Wang Institute of Advanced Photonics Technology School of Information EngineeringGuangdong University of TechnologyGuangzhou 51006China. key Laboratory of Photonic Technology for Integrated Sensing and Communication Ministry of Education of ChinaGuangdong University of TechnologyGuangzhou 51006China. Guangdong Provincial key Laboratory of Information Photonics Technology Guangdong University of TechnologyGuangzhou 51006China. key Laboratory of Advanced Transducers andIntelligent Control System Ministry of EducationTaiyuan University of TechnologyTaiyuan 030024China. State key Laboratory of Transient Optics and Photonics Xi’an Institute of Optics and Precision MechanicsChinese Academy of SciencesXi’an 710119China. Department of Physics and Materials Science City University of Hong KongHong KongChina. School of Electronic Engineering Bangor UniversityBangorWales LL571UTUK

Random bit generators are critical for information security,cryptography,stochastic modeling,and *** and scalability are key challenges faced by current physical random bit ***,we propose a massively parallel scheme for ultrafast random bit generation towards rates of order 100 terabit per second based on a single micro-ring resonator.A modulation-instability-driven chaotic comb in a micro-ring resonator enables the simultaneous generation of hundreds of independent and unbiased random bit streams.A proof-of-concept experiment demonstrates that using our method,random bit streams beyond 2 terabit per second can be successfully generated with only 7 comb *** bit rate can be easily enhanced by further increasing the number of comb lines *** approach provides a chip-scale solution to random bit generation for secure communication and high-performance computation,and offers superhigh speed and large scalability.

关键词： resonator random chaotic

Ultrafast and real-time physical random bit extraction with all-optical quantization

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Advanced Photonics 2022年第3期4卷 83-89页

作者： Ya Guo Qiang Cai Pu Li Ruonan Zhang Bingjie Xu k.Alan shore Yuncai Wang Taiyuan University of Technology Key Laboratory of Advanced Transducers and Intelligent Control SystemsMinistry of EducationTaiyuanChina Guangdong University of Technology School of Information EngineeringGuangdong Provincial Key Laboratory of Photonics Information TechnologyGuangzhouChina Northwestern Polytechnical University School of Electronics and InformationXi’anChina Institute of Southwestern Communication Science and Technology on Communication LaboratoryChengduChina Bangor University School of Electronic EngineeringWalesUnited Kingdom

Optical chaos generated by perturbing semiconductor lasers has been viewed,over recent decades,as an excellent entropy source for fast physical random bit generation(RBG)owing to its high bandwidth and large random ***,most optical-chaos-based random bit generators perform their quantization process in the electrical domain using electrical analog-to-digital converters,so their real-time rates in a single channel are severely limited at the level of Gb/s due to the electronic ***,we propose and experimentally demonstrate an all-optical method for RBG where chaotic pulses are quantized into a physical random bit stream in the all-optical domain by means of a length of highly nonlinear *** our proof-of-concept experiment,a 10-Gb/s random bit stream is successfully generated on-line using our *** that the single-channel real-time rate is limited only by the chaos *** that the kerr nonlinearity of silica fiber with an ultrafast response of few femtoseconds is exploited for composing the key part of quantizing laser chaos,this scheme thus may operate potentially at much higher real-time rates than 100 Gb/s provided that a chaotic entropy source of sufficient bandwidth is available.

关键词： chaos random number generation semiconductor lasers optical signal processing.

Slumping in the Upper Jurassic Baisakhi Formation of the Jaisalmer Basin, western India: Sign of synsedimentary tectonics?

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Journal of Palaeogeography 2017年第4期6卷 321-332页

作者： Matthias Alberti Dhirendra k.Pandey Jitendra k.Sharma Narendra k.Swami Alfred Uchman Institut für Geowissenschaften Christian-Albrechts-Universitt zu Kiel Department of Geology University of Rajasthan Earth & Planetary Sciences Group/Palaeontology Manipal Center for Natural Sciences Manipal University Institute of Geological Sciences Jagiellonian University

A spectacularly exposed slump is described from a 120-m-long road cut between the villages of kanod and Deva in the northeastern Jaisalmer Basin of Rajasthan,*** Upper Jurassic part of the sediments at the outcrop was formed in a near-shore setting and belongs to the Ludharwa Member of the Baisakhi *** 3-m-thick unit shows a number of asymmetric folds and thrust faults leading to an imbrication of partly lithified sandstone *** deformation structures allow the reconstruction of a movement towards the *** agrees well with the basin configuration that shows a deepening into this *** the determination of a specific trigger mechanism is difficult for soft-sediment deformation structures,an earthquake caused by synsedimentary tectonics in the basin seems to be the most likely explanation.

关键词： Sedimentology Mass movements Slumping Soft-sediment deformation structures Jaisalmer Basin Jurassic

High-pressure investigations on Piplia kalan eucrite meteorite using in-situ X-ray diffraction and ^(57)Fe Mssbauer spectroscopic technique up to 16 GPa

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Geoscience Frontiers 2016年第2期7卷 265-271页

作者： Usha Chandra k.k. Pandey G. Parthasarathy Surinder M. Sharma Department of Physics University of Rajasthan Jaipur 302 004 India High Pressure & Synchrotron Radiation Physics Division Bhabha Atomic Research Centre Trombay Mumbai 400 085 India CSIR-National Geophysical Research Institute Uppal Road Hyderabad 500 007 India

We report here high-pressure investigations on Piplia kalan eucrite-a member of HED （Howardite -Eucrite-Diogenite） family from asteroid 4-Vesta based on synchrotron X-ray diffraction （up to 16 GPa） and ^57Fe Mossbauer spectroscopy （up to 8 GPa）. Dominant with anorthite-rich plagioclase, pigeonite-rich pyroxene and clino-ferrosilite, the sample displayed various phase transitions attaining amorphous character at 16 GPa. These phase transitions of individual components could be explained simultaneously through variations in high-pressure XRD patterns and the Mossbauer parameters. Most prominent P21/c to C2/c transition of pigeonite and ferrosilite was exhibited both as sudden variation in Mossbauer parameters and population inversion of Fe^2＋ in M1 and M2 sites between 2.9 and 3.8 GPa and variation in intensity profile in XRD patterns at 3.56 GPa. Anorthite seemed to respond more to such impact than other components in the sample. Complete amorphization in anorthite which occurred at lower pressure of - 12 GPa implied residual stress experienced due to shock impact. The presence of high pressure （monoclinic） phase of pigeonite and ferrosilite at ambient condition in this eucrite sample confirmed earlier suggestions of an early shock event. This report is an attempt to emphasize the role of anorthite in the determination of the residual stress due to impact process in the parent body thus to understand the behavioral differences amongst HED members.

关键词： Meteorites High pressure X-ray diffraction Mossbauer spectroscopy Eucrites synchrotron radiation Ferrosilite

Real-time and ultrafast optical pulse quantization based on slicing the supercontinuum

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Chinese Optics Letters 2021年第8期19卷 69-74页

作者： Ya Guo Qiang Cai Zhiwei Jia Bingjie Xu Zhensen Gao Qianwu Zhang Ruonan Zhang Adonis Bogris k.Alan shore Yuncai Wang Pu Li key Laboratory of Advanced Transducers and Intelligent Control System Ministry of EducationTaiyuan University of TechnologyTaiyuan 030024China School of Information Engineering Guangdong University of TechnologyGuangzhou 510006China key Laboratory of Specialty Fiber Optics and Optical Access Networks Shanghai UniversityShanghai 200444China School of Electronics and Information Northwestern Polytechnical UniversityXi’an 710072China Science and Technology on Communication Security Laboratory Institute of Southwestern CommunicationChengdu 610041China Department of Informatics and Computer Engineering University of West AtticaAthens 12243Greece School of Electronic Engineering Bangor UniversityWales LL571UTUnited Kingdom

All-optical analog-to-digital conversion is a paramount issue in modern science. How to implement real-time and ultrafast quantization to optical pulses with different intensities in an all-optical domain is a central problem. Here, we report a realtime demonstration of an all-optical quantization scheme based on slicing the supercontinuum in a nonlinear fiber. In comparison with previous schemes through off-line analysis of the power of different optical spectral components in the supercontinuum, this, to the best of our knowledge, is the first demonstration of such functionality online in the time ***, the extinction ratio among the quantized outputs can exceed 10 d B, which further confirms the feasibility of the proposed quantization scheme. The current 3 bit resolution in the proof-of-principle experiment is limited by the current experimental condition, but it can be expected to be greatly enhanced through improving both the spectral width of the generated supercontinuum and the number of filtering channels used.

关键词： all-optical analog-to-digital conversion photonic quantization all-optical signal processing supercontinuum generation

Hydrodynamic modeling along the southern tip of India: A special emphasis on kanyakumari coast

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Journal of Ocean Engineering and Science 2017年第4期2卷 229-244页

作者： k.Gurumoorthi R.Venkatachalapathy Faculty of Marine Sciences Annamalai UniversityParangipettai 608502India CSIR-National Institute of Oceanography Dona PaulaGoa 403004India Department of Physics Annamalai UniversityChidambaram 608002India

Hydrodynamic models are important to many coastal engineering designs and application,especially addressing sediment and water *** this study,MIkE 21 two-dimensional(2D)hydrodynamic model based on the flexible mesh(FM)technique was used to simulate the surface currents forced by tides and winds in kanyakumari *** model results of the tidal level along shore and cross shore currents are agreed well with measured data in kanyakumari *** major components of tides and currents are analyzed by harmonic analysis *** mean square error(RMSE)values for the measured and model tides(0.017 m and 0.079 m)and currents(0.025 m/s and 0.009 m/s)during the northeast(NE)and southwest(SW)monsoon period are calculated.A series of scenario runs for NE and SW monsoon season are used to understand the regional *** model result shows that the kanyakumari coast is dominated by tides and surface currents flow,which are influenced by the seasonal reversal wind *** around this coastal water have been evidenced small scale cyclonic and anti-cyclonic eddies ranged from∼55 to 120 km in *** cyclonic and anti-cyclonic eddies are mostly appeared in near kanyakumari and SE coast of kerala due to local/remotely generated forces.

关键词： Hydrodynamic model Tide Surface circulation Eddy kanyakumari Southern tip of India

Review of near-shore satellite derived bathymetry: Classification and account of five decades of coastal bathymetry research

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Journal of Ocean Engineering and Science 2021年第4期6卷 340-359页

作者： Mohammad Ashphaq Pankaj k Srivastava D Mitra National Hydrographic Office DehradunIndia University of Petroleum&Energy Studies(UPES) DehradunIndia Indian Institute of Remote Sensing DehradunIndia

The number of civilian,commercial and military applications are dependant on accurate knowledge of bathymetry of coastal ***,hydrographic surveying methods are used for bathymetric surveys carried by ship-based acoustic systems,but needs highcost *** technology has provided a cost-effective alternate means for charting near shore and inaccessible *** optical satellite data have capabilities to offer alternate solution in near-shore region,which has been researched for past 50 years,using evolving algorithms to estimate Satellite Derived Bathymetry(SDB).However,there is no agreement on use of terms like approach,model,method and techniques,which have been used varyingly and interchangeably as per context of SDB *** paper suggests a classification scheme for SDB algorithms which is also applicable to other Marine Remote Sensing *** this paper,based on literature available on SDB for the past five decades,an insight on SDB classification has been offered grounded in research *** SDB approaches,models,methods and techniques have been elaborated with chronological development,along with SDB studies based on them,their accuracy and errors in SDB *** have suggested a matrix of prerequisite satellite data,in-situ data resolution,methods and algorithms of SDB based on level of accuracy needs to be achieved,which will guide future researchers to select one as per their context of research.

关键词： Satellite derived bathymetry Hydrography Bio-optical model Physio-optical model

Long-term coastal erosion assessment along the coast of karnataka,west coast of India

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International Journal of Sediment Research 2019年第4期34卷 335-344页

作者： k.Sowmya M.Dhivya Sri Aparna S.Bhaskar k.S.Jayappa Department of Marine Geology Mangalore University Department of Geography University of Madras Department of Civil Engineering SRM Institute of Science and Technology

Coastal areas are always under frequent threat from various natural processes and man-induced *** erosion is recognized as the permanent loss of land along the shoreline resulting in the transformation of the coast. The current study focuses on long-term coastal erosion analysis of the entire karnataka coast using Remote Sensing, Geographical Information System(GIS), Linear Regression Rate(LRR), and End Point Rate(EPR) techniques. Analysis of 26(1990 to 2016) years of erosion using Landsat images by the use of the Digital shoreline Analysis System(DSAS) tool has been done. The results show a high erosion rate at Ullal during this period(LRR-1.3 m/yr) and accretion at Devbagh(LRR 3.2 m/yr). The southern karnataka coast faces severe erosion especially at Ullal, where the settlement is high. At Thanirbhavi, Mukka, kota,and Om Beaches erosion also is noticed. Both anthropogenic activities like ports, seawalls, breakwaters, *** natural processes like long shore drift, seasonal variation, etc. are factors affecting the shoreline change along the karnataka coast.

关键词： karnataka coast Landsat images Erosion Linear Regression Rate End Point Rate

Characterization and seasonal distribution of microplastics in the nearshore sediments of the south-east coast of India,Bay of Bengal

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Frontiers of Environmental Science & Engineering 2022年第1期16卷 129-139页

作者： k.Dhineka M.Sambandam S.k.Sivadas T.kaviarasan Umakanta Pradhan Mehmuna Begum Pravakar Mishra M.V.Ramana Murthy National Centre for Coastal Research(NCCR) Ministry of Earth Science(MoES)Chennai 600100India*

In view of increasing Microplastics(MPs)contamination in the marine environment and dearth of baseline data,a study was conducted on the abundance,characterization,and seasonal distribution of MPs in the nearshore sediments of the south-east coast of *** samples(n=130)were collected at a distance of 1 km and 10 km from the shore region at varying depths(8–45 m)along the Chennai to Puducherry coast(165 km stretch),representing two seasons,i.e.,south-west(July 2019 and July 2020)and north-east(January 2020)*** average abundance of MPs at the 22 offshore sites along the Chennai to Puducherry coast varied from 9±4.3 to 19±12.9 particles/50 g dry weight,in July 2019 and January 2020,*** 2020 had an average abundance of 10±4.5 particles/50 g dry ***,high levels of MPs were found at 1km stations and transects in proximity to the river inlets,and temporally,the north-east month recorded the maximum *** dominant morphotype was the filament,and the major polymers were polyethylene and *** Electron Microscope(SEM)images revealed the surface irregularity and degradation of MPs due to *** study highlights that high sediment contamination by MPs occurs during heavy rainfall and accumulates closer to river ***,this study suggests that appropriate management of plastic wastes on the landside will reduce MP contamination in the marine environment.

关键词： Microplastics Coastal sediment Characterization Bay of Bengal India