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Jan Danckaert

Bio: Jan Danckaert is an academic researcher from Vrije Universiteit Brussel. The author has contributed to research in topics: Semiconductor laser theory & Laser. The author has an hindex of 37, co-authored 255 publications receiving 4686 citations. Previous affiliations of Jan Danckaert include École nationale supérieure d'électronique et de radioélectricité de Grenoble & University of Pavia.


Papers
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Journal ArticleDOI
TL;DR: This work introduces a novel architecture that reduces the usually required large number of elements to a single nonlinear node with delayed feedback and proves that delay-dynamical systems, even in their simplest manifestation, can perform efficient information processing.
Abstract: Novel methods for information processing are highly desired in our information-driven society. Inspired by the brain's ability to process information, the recently introduced paradigm known as 'reservoir computing' shows that complex networks can efficiently perform computation. Here we introduce a novel architecture that reduces the usually required large number of elements to a single nonlinear node with delayed feedback. Through an electronic implementation, we experimentally and numerically demonstrate excellent performance in a speech recognition benchmark. Complementary numerical studies also show excellent performance for a time series prediction benchmark. These results prove that delay-dynamical systems, even in their simplest manifestation, can perform efficient information processing. This finding paves the way to feasible and resource-efficient technological implementations of reservoir computing.

1,121 citations

Journal ArticleDOI
TL;DR: In this article, a mechanism for polarization switching in slightly anisotropic vertical-cavity surface-emitting lasers (VCSELs) based on index guiding due to the effect of thermal lensing was demonstrated.
Abstract: We demonstrate a new mechanism for polarization switching in slightly anisotropic vertical-cavity surface-emitting lasers (VCSEL's) based on index guiding due to the effect of thermal lensing. This polarization switching takes place when the laser operates on the short-wavelength side of the gain maximum. The two orthogonal linear polarizations correspond to slightly different wavelengths and switching occurs from shorter toward longer laser wavelength as the drive current increases. Polarization modulation has been observed up to 50 MHz with a polarization contrast ratio of 20:1.

144 citations

Journal ArticleDOI
TL;DR: In this paper, the effect of the photon energy and temperature dependence of both the gain and the total losses inside the cavity was analyzed to understand the polarization behavior of vertical-cavity surface-emitting lasers.
Abstract: We have analyzed the effect of the photon energy and temperature dependence of both the gain and the total losses inside the cavity to understand the polarization behavior of vertical-cavity surface-emitting lasers. The assumption that the losses are dominated by free-carrier absorption in the p-doped mirror is made. Developing a new theoretical approach, we are able to predict different polarization switching regimes in which switching occurs from the high- to the low-frequency mode, from the low- to the high-frequency mode, or both consecutively. All these predictions have been experimentally verified by our measurements on GaAs/AlGaAs proton-implanted vertical-cavity surface-emitting lasers.

130 citations

Journal ArticleDOI
22 Sep 2008-Chaos
TL;DR: The relation between the theoretical results on delay-coupled Kuramoto oscillators and the synchronization properties of networks consisting of real-world delay-Coupled oscillators, such as semiconductor laser arrays and neuronal circuits is discussed.
Abstract: We investigate the effect of coupling delays on the synchronization properties of several network motifs. In particular, we analyze the synchronization patterns of unidirectionally coupled rings, bidirectionally coupled rings, and open chains of Kuramoto oscillators. Our approach includes an analytical and semianalytical study of the existence and stability of different in-phase and out-of-phase periodic solutions, complemented by numerical simulations. The delay is found to act differently on networks possessing different symmetries. While for the unidirectionally coupled ring the coupling delay is mainly observed to induce multistability, its effect on bidirectionally coupled rings is to enhance the most symmetric solution. We also study the influence of feedback and conclude that it also promotes the in-phase solution of the coupled oscillators. We finally discuss the relation between our theoretical results on delay-coupled Kuramoto oscillators and the synchronization properties of networks consisting of real-world delay-coupled oscillators, such as semiconductor laser arrays and neuronal circuits.

129 citations

Journal ArticleDOI
TL;DR: In this article, the presence of switching between two fundamental modes with orthogonal linear polarization in vertical-cavity surface-emitting lasers and the current at which this phenomenon occurs depend on both the magnitude and the orientation of an externally induced in-plane anisotropic strain.
Abstract: We experimentally demonstrate that the presence of switching between two fundamental modes with orthogonal linear polarization in vertical-cavity surface-emitting lasers and the current at which this phenomenon occurs depend on both the magnitude and the orientation of an externally induced in-plane anisotropic strain. We interpret this behavior by considering the anisotropy in gain and in refractive index, both induced by the in-plane strain, and by accounting for a redshift of the two gain curves as a result of current-induced heating.

113 citations


Cited by
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[...]

08 Dec 2001-BMJ
TL;DR: There is, I think, something ethereal about i —the square root of minus one, which seems an odd beast at that time—an intruder hovering on the edge of reality.
Abstract: There is, I think, something ethereal about i —the square root of minus one. I remember first hearing about it at school. It seemed an odd beast at that time—an intruder hovering on the edge of reality. Usually familiarity dulls this sense of the bizarre, but in the case of i it was the reverse: over the years the sense of its surreal nature intensified. It seemed that it was impossible to write mathematics that described the real world in …

33,785 citations

28 Jul 2005
TL;DR: PfPMP1)与感染红细胞、树突状组胞以及胎盘的单个或多个受体作用,在黏附及免疫逃避中起关键的作�ly.
Abstract: 抗原变异可使得多种致病微生物易于逃避宿主免疫应答。表达在感染红细胞表面的恶性疟原虫红细胞表面蛋白1(PfPMP1)与感染红细胞、内皮细胞、树突状细胞以及胎盘的单个或多个受体作用,在黏附及免疫逃避中起关键的作用。每个单倍体基因组var基因家族编码约60种成员,通过启动转录不同的var基因变异体为抗原变异提供了分子基础。

18,940 citations

01 Jan 2016
TL;DR: In this paper, the authors present the principles of optics electromagnetic theory of propagation interference and diffraction of light, which can be used to find a good book with a cup of coffee in the afternoon, instead of facing with some infectious bugs inside their computer.
Abstract: Thank you for reading principles of optics electromagnetic theory of propagation interference and diffraction of light. As you may know, people have search hundreds times for their favorite novels like this principles of optics electromagnetic theory of propagation interference and diffraction of light, but end up in harmful downloads. Rather than enjoying a good book with a cup of coffee in the afternoon, instead they are facing with some infectious bugs inside their computer.

2,213 citations

Journal ArticleDOI
01 Jul 2017
TL;DR: A new architecture for a fully optical neural network is demonstrated that enables a computational speed enhancement of at least two orders of magnitude and three order of magnitude in power efficiency over state-of-the-art electronics.
Abstract: Artificial Neural Networks have dramatically improved performance for many machine learning tasks. We demonstrate a new architecture for a fully optical neural network that enables a computational speed enhancement of at least two orders of magnitude and three orders of magnitude in power efficiency over state-of-the-art electronics.

1,955 citations