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Taking silicon photonics modulators to a higher performance level: state-of-the-art and a review of new technologies

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Advanced Photonics 2021年第2期3卷 38-60页

作者： Abdul Rahim Artur Hermans Benjamin Wohlfeil Despoina Petousi Bart Kuyken Dries Van Thourhout roel baets Ghent University Photonics Research GroupDepartment of Information TechnologyGhentBelgium Ghent University IMEC and Center for Nano-and BiophotonicsGhentBelgium ADVA Optical Networking BerlinGermany

Optical links are moving to higher and higher transmission speeds while shrinking to shorter and shorter ranges where optical links are envisaged even at the chip *** scaling in data speed and span of the optical links demands modulators to be concurrently performant and *** photonics(SiPh),a photonic integrated circuit technology that leverages the fabrication sophistication of complementary metal-oxide-semiconductor technology,is well-positioned to deliver the performance,price,and manufacturing volume for the high-speed modulators of future optical communication *** has relied on the plasma dispersion effect,either in injection,depletion,or accumulation mode,to demonstrate efficient high-speed *** high-speed plasma dispersion silicon modulators have been commercially deployed and have demonstrated excellent *** years have seen a paradigm shift where the integration of various electro-refractive and electro-absorptive materials has opened up additional routes toward performant SiPh *** modulators are in the early years of their *** promise to extend the performance beyond the limits set by the physical properties of *** focus of our study is to provide a comprehensive review of contemporary(i.e.,plasma dispersion modulators)and new modulator implementations that involve the integration of novel materials with SiPh.

关键词： high-speed modulators silicon photonics plasma dispersion effect ferroelectrics graphene III-V on Si organic(electro-optic)materials.

Widely tunable 2.3μm III-V-on-silicon Vernier lasers for broadband spectroscopic sensing

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Photonics Research 2018年第9期6卷 858-866页

作者： RUIJUN WANG STEPHAN SPRENGEL ANTON VASILIEV GERHARD BOEHM JORIS VAN CAMPENHOUT GuY LEPAGE PETER VERHEYEN roel baets MARKUS-CHRISTIAN AMANN GUNTHER roelKENS Photonics Research Group Ghent University-IMECTechnologiepark-Zwijnaarde 15B-9052 GhentBelgium Center for Nano-and Biophotonics(NB-Photonics) Ghent UniversityB-9052 GhentBelgium Walter Schottky Institut Technische Universitat MunchenAm Coulombwall 485748 GarchingGermany IMEC Kapeldreef 75Leuven B-3001Belgium

Heterogeneously integrating III-V materials on silicon photonic integrated circuits has emerged as a promising approach to make advanced laser sources for optical communication and sensing applications. Tunable semiconductor lasers operating in the 2–2.5 μm range are of great interest for industrial and medical applications since many gases(e.g., CO_2, CO, CH_4) and biomolecules(such as blood glucose) have strong absorption features in this wavelength region. The development of integrated tunable laser sources in this wavelength range enables low-cost and miniature spectroscopic sensors. Here we report heterogeneously integrated widely tunable III-V-on-silicon Vernier lasers using two silicon microring resonators as the wavelength tuning components. The laser has a wavelength tuning range of more than 40 nm near 2.35 μm. By combining two lasers with different distributed Bragg reflectors, a tuning range of more than 70 nm is achieved. Over the whole tuning range, the side-mode suppression ratio is higher than 35 dB. As a proof-of-principle, this III-V-on-silicon Vernier laser is used to measure the absorption lines of CO. The measurement results match very well with the high-resolution transmission molecular absorption(HITRAN) database and indicate that this laser is suitable for broadband spectroscopy.

关键词：硅光子集成电路通讯技术发展现状

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将激光集成到硅上的4种方法

科技纵览 2023年第5期 32-37,4页

作者： roel baets Joris Van Campenhout Bernardette Kunert Gunther roelkens 不详

在日常生活中,将一系列光电子功能集合在一块芯片上的光子集成电路越来越常见,它们被用于连接数据中心服务器机架的高速光收发器(包括用于提供本刊网站的光收发器)、保持自动驾驶汽车正常行驶的激光雷达、发现大气中化学物质的光谱仪,... 详细信息

在日常生活中,将一系列光电子功能集合在一块芯片上的光子集成电路越来越常见,它们被用于连接数据中心服务器机架的高速光收发器(包括用于提供本刊网站的光收发器)、保持自动驾驶汽车正常行驶的激光雷达、发现大气中化学物质的光谱仪,以及许多其他应用。所有这些系统都变得越来越便宜,并且在某些情况下,使用硅制造技术生产大部分集成电路也是经济可行的。

关键词：化学物质集成电路激光雷达自动驾驶汽车数据中心服务器光谱仪光电子硅

Silicon and silicon nitride photonic circuits for spectroscopic sensing on-a-chip [Invited]

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Photonics Research 2015年第5期3卷 47-59页

作者： Ananth Z.Subramanian Eva Ryckeboer Ashim Dhakal Frédéric Peyskens Aditya Malik Bart Kuyken Haolan Zhao Shibnath Pathak Alfonso Ruocco Andreas De Groote Pieter Wuytens Daan Martens Francois Leo Weiqiang Xie Utsav Deepak Dave Muhammad Muneeb Pol Van Dorpe Joris Van Campenhout Wim Bogaerts Peter Bienstman Nicolas Le Thomas Dries Van Thourhout Zeger Hens Gunther roelkens roel baets Photonics Research Group INTEC Department Ghent University-imec Centre for Nano and Biophotonics Ghent University University of California Department of Molecular Biotechnology Ghent University imec Kapeldreef 75 Physics and Chemistry of Nanostructures Ghent University

There is a rapidly growing demand to use silicon and silicon nitride（Si3N4） integrated photonics for sensing applications, ranging from refractive index to spectroscopic sensing. By making use of advanced CMOS technology,complex miniaturized circuits can be easily realized on a large scale and at a low cost covering visible to mid-IR wavelengths. In this paper we present our recent work on the development of silicon and Si3N4-based photonic integrated circuits for various spectroscopic sensing applications. We report our findings on waveguide-based absorption, and Raman and surface enhanced Raman spectroscopy. Finally we report on-chip spectrometers and on-chip broadband light sources covering very near-IR to mid-IR wavelengths to realize fully integrated spectroscopic systems on a chip.

关键词： Invited SOI mode

Is a catalyst always beneficial in plasma catalysis? Insights from the many physical and chemical interactions

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Journal of Energy Chemistry 2023年第10期85卷 501-533,I0013页

作者： Björn Loenders roel Michiels Annemie Bogaerts Research group PLASMANT Department of ChemistryUniversity of AntwerpUniversiteitsplein 1B-2610 Wilrijk-AntwerpBelgium

Plasma-catalytic dry reforming of CH_(4)(DRM) is promising to convert the greenhouse gasses CH_(4) and CO_(2) into value-added chemicals, thus simultaneously providing an alternative to fossil resources as feedstock for the chemical industry. However, while many experiments have been dedicated to plasma-catalytic DRM, there is no consensus yet in literature on the optimal choice of catalyst for targeted products,because the underlying mechanisms are far from understood. Indeed, plasma catalysis is very complex,as it encompasses various chemical and physical interactions between plasma and catalyst, which depend on many parameters. This complexity hampers the comparison of experimental results from different studies, which, in our opinion, is an important bottleneck in the further development of this promising research field. Hence, in this perspective paper, we describe the important physical and chemical effects that should be accounted for when designing plasma-catalytic experiments in general, high-lighting the need for standardized experimental setups, as well as careful documentation of packing properties and reaction conditions, to further advance this research field. On the other hand, many parameters also create many windows of opportunity for further optimizing plasma-catalytic ***, various experiments also reveal the lack of improvement in plasma catalysis compared to plasma-only, specifically for DRM, but the underlying mechanisms are unclear. Therefore, we present our newly developed coupled plasma-surface kinetics model for DRM, to provide more insight in the underlying reasons. Our model illustrates that transition metal catalysts can adversely affect plasmacatalytic DRM, if radicals dominate the plasma-catalyst interactions. Thus, we demonstrate that a good understanding of the plasma-catalyst interactions is crucial to avoiding conditions at which these interactions negatively affect the results, and we provide some recommendations for im

关键词： Plasma catalysis Dry reforming of methane Discharges Reaction kinetics Modelling

Do birds in flight respond to(ultra)violet lighting?

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Avian Research 2017年第4期8卷 192-201页

作者： roel May Jens Astrom Oyvind Hamre Espen Lie Dahl Terrestrial Ecology Department Norwegian Institute for Nature Research(NINA)TrondheimNorway Steinoysund SmolaNorway.

Background: Concerns for bird collisions with wind turbines affect the deployment of onshore and offshore windpower *** avoid delays in consenting processes and to streamline the construction and operation phase,functional mitigation measures are required which efficiently reduces bird *** is the primary sensory system in birds,which for a number of species also includes the ultraviolet *** bird species that are known to collide with offshore wind turbines are sensitive in the violet or ultraviolet *** species that are mainly active at lower ambient light levels,lighting may deter birds from the lit ***(ultra)violet lights may in addition not disturb ***,we do not know whether UV-sensitive birds in flight actually respond behaviourally to UV ***: We therefore tested the efficacy of two types of lights within the violet(400 nm) and ultraviolet(365 nm) spectrum to deter birds from the lit *** lights were placed vertically and monitored continuously between dusk and dawn using an avian radar ***: Relative to control nights,bird flight activity(abundance) was 27% lower when the ultraviolet light was *** light resulted in a 12% decrease in overall abundance,and in addition,a vertical displacement was seen,increasing the average flight altitude by 7 *** temporal changes occurred,this effect persisted over the season below 40 m above sea ***: Although the results from this pilot study are promising,we argue there still is a long way to go before a potentially functional design to mitigate collisions that has proven to be effective in situ may be in place.

关键词： Avian radar Displacement Habituation Mitigation Seabirds Ultraviolet Wind turbine

Sino-European Space Cooperation——A Comparative Analysis of Galileo and Double Star

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Sino-European Space Cooperation——A Comparative Analysis of...

作者： roel Gremmen 上海交通大学

学位级别：硕士

The solution of many international challenges,like climate change and ozone depletion,depends on effective international scientific and technological（S＆T）***,numerous international security concerns depend on *** China and the EU emphasise the development of space science and technology,and the process of institution-building has been paving the way for the further development of bilateral ***,history suggests that space technology often originates from military defence,and then spreads to the field of civilian ***,space S ＆ T has an important significance both on a security level as well as on a commercial *** S ＆ T is highly advanced technology,vital for national security and often top-secret,and it has been regarded as a competitive and closed *** is it possible for China and Europe to cooperate in a strategic field? Which vital factors drive the cooperative motivation of both actors? Are they looking for a balance of power,pursuing common interests,or operating on mutual trust? Why do some joint programmes advance smoothly,such as the Double Star programme,and do some programmes,such as the Galileo cooperation,fail? Two in-depth case studies are presented in this *** making a comparative analysis between the successful Double Star Project and the unsuccessful Galileo project to determine which factors contributed to the ultimate outcome of the programmes.I argue that the EU is motivated by its goal to move away from dependence on US technology,and the idea of utilizing space solely for maximisation of security,rather than treating it as a common good that can be *** on its turn is mainly looking to further develop and modernise its space technology and partnered with Europe to circumvent the restrictions of the ***,scientific institutions encourage cooperation for the sake of science ***,those institutions are currently the main way through wh

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Application of the Point-Descriptor-Precedence representation for micro-scale traffic analysis at a non-signalized T-junction

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Geo-Spatial Information Science 2023年第3期26卷 406-430页

作者： Amna Qayyum Bernard De baets Laure De Cock Frank Witlox Guy De Tré Nico Van de Weghe Department of Geography Ghent UniversityGhentBelgium Department of Data Analysis and Mathematical Modelling Ghent UniversityGhentBelgium Department of Telecommunications and Information Processing Ghent UniversityGhentBelgium

An intersection of two or more roads poses a risk for potential conflicts among *** the reasons triggering such conflicts are not clear,as they might be too subtle for the human *** environment also plays a part in understanding where,when,and why a particular vehicle interaction has occurred in a certain ***,it is of paramount importance to dive deeper into the vehicle interaction at a micro-scale within the embedded geographical environment,particularly at the *** would in turn assist in evaluating the association of vehicle interactions with conflict risks and near-miss ***,detection of such micro traffic interactions could also be used to improvise the complexity of the already established transport ***,traffic at intersections has been explored mainly for flow estimation,capacity and width measurements,and traffic congestion,etc.,whereas the detection of micro-scale traffic interactions at intersections remains relatively *** this paper,we present a novel approach to retrieve and represent micro-scale traffic movement interactions at a non-signalized T-junction by extending a recently introduced qualitative spatiotemporal Point-Descriptor-Precedence(PDP)*** study how the PDP representation offers a fine solution to study the interaction of traffic flows at *** permits tracking the micro-movement of vehicles in much finer detail,which is used later to retrieve movement patterns from a motion *** conventional approaches,we start our approach with the actual movements before modeling the static intersection ***,with the aid of illustrative examples,we discuss how the length,width,and speed of the vehicles can be exploited in our approach to detect specific patterns more ***,we address the potential benefits of our approach for traffic safety assessment and how it can be extended to a network of

关键词： Vehicle interaction traffic research pattern identification traffic safety spatiotemporal representation movement pattern

Equipartitioning is not sufficient for Green's function extraction

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Earthquake Science 2010年第5期23卷 403-415页

作者： roel Snieder Yuanzhong Fan Evert Slob Kees Wapenaar Center for Wave Phenomena Colorado School of Mines Golden CO 80401 USA Faculty of Civil Engineering and Geosciences Delft University of Technology 2600 GA Delft Netherlands

The extraction of the Earth＇s Green＇s function from field fluctuations is a rapidly growing area of research. The principle of Green＇s function extraction is often related to the requirement of equipartitioning, which stipulates that the energy of field fluctuations is distributed evenly in some sense. We show the meaning of equipartitioning for a variety of different formulations for Green＇s function retrieval. We show that equipartitioning is not a sufficient condition, and provide several examples that illustrate this point. We discuss the implications of lack of equipartitioning for various schemes for the reconstruction of the Green＇s function in seismology. The theory for Green＇s function extraction is usually based on a statistical theory that relies on ensemble averages. Since there is only one Earth, one usually replaces the ensemble average with a time average. We show that such a replacement only makes sense when attenuation is taken into account, and show how the theory for Green＇s function extraction for oscillating systems can be extended to incorporate attenuation.

关键词： seismic interferometry Green's function retrieval equipartitioning