Dr. Lendert Gelens Profile

Dr. Lendert Gelens

PhD Researcher at Vrije Univ Brussel

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Publications (13)

Proceedings Article | 27 April 2016 Presentation + Paper

Characterizing the dynamics of cavity solitons and frequency combs in the Lugiato-Lefever equation

P. Parra-Rivas, D. Gomila, L. Gelens

Proceedings Volume 9894, 989403 (2016) https://doi.org/10.1117/12.2225591

KEYWORDS: Dispersion, Solitons, Frequency combs, Microresonators, Chaos, Optical testing, Optical microcavities, Optical resonators, Nonlinear optics, Radio propagation, Modulation, Medicine

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Proceedings Article | 2 May 2014 Paper

Two semiconductor ring lasers coupled by a single-waveguide for optical memory operation

Guy Van der Sande, Werner Coomans, Lendert Gelens

Proceedings Volume 9134, 91341V (2014) https://doi.org/10.1117/12.2051961

KEYWORDS: Semiconductor lasers, Waveguides, Semiconductors, Optical storage, Laser resonators, Photonic integrated circuits, Phase shifts, Laser optics, Switching, Integrated optics

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Semiconductor ring lasers are semiconductor lasers where the laser cavity consists of a ring-shaped waveguide. SRLs are highly integrable and scalable, making them ideal candidates for key components in photonic integrated circuits. SRLs can generate light in two counterpropagating directions between which bistability has been demonstrated. Hence, information can be coded into the emission direction. This bistable operation allows SRLs to be used in systems for all-optical switching and as all-optical memories. For the demonstration of fast optical flip-flop operation, Hill et al. [Nature 432, 206 (2004)] fabricated two SRLs coupled by a single waveguide, rather than a solitary SRL. Nevertheless, the literature shows that a single SRL can also function perfectly as an all-optical memory. In our recent paper [W. Coomans et al., Phys. Rev. A 88, 033813, (2013)], we have raised the question whether coupling two SRLs to realize a single optical memory has any advantage over using a solitary SRL, taking into account the obvious disadvantage of a doubled footprint and power consumption. To provide the answer, we have presented in that paper a numerical study of the dynamical behavior of semiconductor ring lasers coupled by a single bus waveguide, both when weakly coupled and when strongly coupled. We have provided a detailed analysis of the multistable landscape in the coupled system, analyzed the stability of all solutions and related the internal dynamics in the individual lasers to the field effectively measured at the output of the waveguide. We have shown which coupling phases generally promote instabilities and therefore need to be avoided in the design. Regarding all-optical memory operation, we have demonstrated that there is no real advantage for bistable memory operation compared to using a solitary SRL. An increased power suppression ratio has been found to be mainly due to the destructive interference of the SRL fields at the low power port. Also, multistability between several modal configurations has been shown to remain unavoidable.

Proceedings Article | 1 May 2014 Paper

Spatio-temporal stability of 1D Kerr cavity solitons

L. Gelens, P. Parra-Rivas, F. Leo, D. Gomila, Manuel Matias, S. Coen

Proceedings Volume 9136, 91360J (2014) https://doi.org/10.1117/12.2052455

KEYWORDS: Solitons, Chaos, Resonators, Bistability, Microresonators, Radio propagation, Complex systems, Optical turbulence, Fabry–Perot interferometers, Frequency combs

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Proceedings Article | 1 May 2014 Paper

Modeling Kerr frequency combs using the Lugiato-Lefever equation: a characterization of the multistable landscape

P. Parra-Rivas, D. Gomila, M. Matias, F. Leo, S. Coen, L. Gelens

Proceedings Volume 9136, 91361V (2014) https://doi.org/10.1117/12.2052383

KEYWORDS: Frequency combs, Resonators, Chaos, Microresonators, Continuous wave operation, Dispersion, Light, Solitons, Modulation, Optical testing

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Proceedings Article | 15 May 2012 Paper

Experimental and numerical study of square wave oscillations due to asymmetric optical feedback in semiconductor ring lasers

Lilia Mashal, Guy Van der Sande, Lendert Gelens, Stefano Beri, Thomas Erneux, Jan Danckaert, Guy Verschaffelt

Proceedings Volume 8432, 84321R (2012) https://doi.org/10.1117/12.921953

KEYWORDS: Semiconductor lasers, Semiconductors, Optical fibers, Continuous wave operation, Backscatter, Waveguides, Polarization, Optical semiconductors, Stochastic processes

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Proceedings Article | 15 May 2012 Paper

Semiconductor ring lasers as optical neurons

W. Coomans, L. Gelens, L. Mashal, S. Beri, G. Van der Sande, J. Danckaert, G. Verschaffelt

Proceedings Volume 8432, 84321I (2012) https://doi.org/10.1117/12.922269

KEYWORDS: Semiconductor lasers, Laser optics, Semiconductors, Neurons, Waveguides, Neural networks, Integrated optics, Numerical simulations, Continuous wave operation

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Proceedings Article | 15 May 2012 Paper

Nonlinear dynamics in directly modulated semiconductor ring lasers

S. Takougang Kingni, G. Van der Sande, L. Gelens, J. Danckaert

Proceedings Volume 8432, 84321Q (2012) https://doi.org/10.1117/12.921949

KEYWORDS: Modulation, Semiconductor lasers, Chaos, Nonlinear dynamics, Semiconductors, Backscatter, Physics, Adaptive optics, Applied physics

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Proceedings Article | 28 April 2010 Paper

Analysis of multistability in semiconductor ring lasers

L. Gelens, S. Beri, G. Van der Sande, G. Mezosi, M. Sorel, J. Danckaert, G. Verschaffelt

Proceedings Volume 7720, 772029 (2010) https://doi.org/10.1117/12.854761

KEYWORDS: Semiconductor lasers, Waveguides, Semiconductors, Oscilloscopes, Space operations, Bismuth, Multimode fibers, Time metrology, Stochastic processes

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Proceedings Article | 28 April 2010 Paper

Dynamical regimes in an optically injected semiconductor ring laser

W. Coomans, S. Beri, G. Van der Sande, L. Gelens, J. Danckaert

Proceedings Volume 7720, 77201Z (2010) https://doi.org/10.1117/12.854342

KEYWORDS: Semiconductor lasers, Laser optics, Semiconductors, Optical semiconductors, Laser systems engineering, Numerical simulations, Integrated optics, Waveguides, Switching

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Proceedings Article | 28 April 2010 Paper

Study of excitability in semiconductor ring lasers: theory and experiment

Lilia Mashal, Stefano Beri, Lendert Gelens, Guy Van der Sande, Gabor Mezosi, Marc Sorel, Jan Danckaert, Guy Verschaffelt

Proceedings Volume 7720, 772028 (2010) https://doi.org/10.1117/12.854741

KEYWORDS: Semiconductor lasers, Waveguides, Semiconductors, Stochastic processes, Optical fibers, Biomedical optics, Bistable lasers, Laser optics, Photodiodes

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Semiconductor Ring Lasers (SRLs) are a novel class of semiconductor lasers whose active cavity is characterized by a circular geometry. SRLs have attracted attention due to the possibility of monolithical integration of thousands of them on the same chip in a cheap and reliable way. SRLs are interesting for applications that rely on the presence of two counter-propagating modes inside the optical cavity. For instance, fully symmetric coupled SRLs have been proposed as candidates for the realisation of small and fast all-optical memories. At the same time, a wealth of nonlinear and stochastic dynamics have been predicted and observed in symmetric SRLs which is a consequence of the underlying Z2-symmetry of the device. However, unavoidable fabrication defects, material roughness and chip-cleaving break the device symmetry in an uncontrolled and unpredictable way, which may result in a deterioration of the device's performance in applications such as all-optical signal-processing. Despite their importance, the effects of symmetry breaking in SRLs remain unaddressed. In this contribution we investigate theoretically and experimentally the stochastic dynamics of SRLs with weakly broken Z2-symmetry . We show how the symmetry of an SRL can be experimentally manipulated using the reflection from a cleaved facet of a multi-mode optical fibre and a control electrode on the bus waveguide. The experiments are performed on an InP-based multi-quantum well SRL operating in single-longitudinal mode regime. The power at the CCW output is collected using a fast photodiode connected to an oscilloscope with a sampling rate of 4.0 ns. For a not-too-weak symmetry breaking, we reveal that SRLs become excitable and therefore can emit large, deterministic power bursts as a response to stochastic fluctuations. The origin of excitability is explained by investigating the topology of the invariant manifolds of an asymptotic two-dimensional phase space model with broken Z2-invariance. The results of the experiments confirm the prediction of the theory.

Proceedings Article | 27 April 2010 Paper

Theoretical and experimental investigation of mode-hopping in semiconductor ring lasers

Stefano Beri, Lendert Gelens, Miquel Mestre, Guy Van der Sande, Gabor Mezosi, Marc Sorel, Guy Verschaffelt, Jan Danckaert

Proceedings Volume 7720, 77200O (2010) https://doi.org/10.1117/12.854371

KEYWORDS: Semiconductor lasers, Stochastic processes, Semiconductors, Waveguides, Numerical simulations, Oscilloscopes, Complex systems, Diffusion, Backscatter

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Proceedings Article | 8 May 2008 Paper

The dynamic behavior of a semiconductor ring laser

Guy Van der Sande, Lendert Gelens, Philippe Tassin, Alessandro Scirè, Jan Danckaert

Proceedings Volume 6997, 699718 (2008) https://doi.org/10.1117/12.781503

KEYWORDS: Semiconductor lasers, Backscatter, Semiconductors, Laser damage threshold, Modes of laser operation, Carbon dioxide lasers, Continuous wave operation, Mathematical modeling, Laser stabilization, Solid state lasers

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Proceedings Article | 6 May 2008 Paper

Sub-diffraction-limited localized structures: influence of linear non-local interactions

L. Gelens, G. Van der Sande, P. Tassin, D. Gomila, P. Colet, M. A. Matías, M. Tlidi, P. Kockaert, I. Veretennicoff, J. Danckaert

Proceedings Volume 6987, 69870B (2008) https://doi.org/10.1117/12.781366

KEYWORDS: Diffraction, Solitons, Metamaterials, Resonators, Solids, Optical resonators, Nonlinear optics, Modulation, Stereolithography, Microresonators

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Showing 5 of 13 publications

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