U. Röpke

Leibniz Institute of Photonic Technology

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Co-Authors

Hartmut Bartelt

Leibniz Institute of Photonic Technology

Kay Schuster

Heraeus (Germany)

J. Kobelke

Leibniz Institute of Photonic Technology

Stefan Nolte

Fraunhofer Institute for Applied Optics and Precision Engineering

Falk Eilenberger

Fraunhofer Institute for Applied Optics and Precision Engineering

Thomas Pertsch

Friedrich Schiller University Jena

S. Jetschke

Leibniz Institute of Photonic Technology

Stefano Minardi

OSRAM (United States)

Andreas Tünnermann

Friedrich Schiller University Jena

J. Kirchhof

Leibniz Institute of Photonic Technology

Cooperative Institutions

Leibniz Institute of Photonic Technology

Helmholtz Institute Jena

Friedrich Schiller University Jena

Albert Einstein College of Medicine

Klinik für Psychosomatik

Fraunhofer Institute for Applied Optics and Precision Engineering

Schiller International University

Foundation for Research and Technology Hellas

Heidelberg University

University of Geneva

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Nonlinear Spectral Symmetry Breaking of Light Bullets in Waveguide Arrays

Conference on Lasers and Electro-Optics (2012)

Falk Eilenberger Stefano Minardi Alexander Szameit U. Röpke Jens Kobelke

We investigate the impact of the wavelength dependence of the discrete diffraction on the dynamics of Light Bullets (LBs) in a periodic medium. This dependence gives rise to a strong spatiotemporal coupling, which in turn leads to a spatiotemporally modified LB spectrum. This nonlinear spectral reshaping is measured and analyzed. It is found numerically and in experiment that it can be used to measure the strength of spatiotemporal coupling.

Waveguide

Coupling strength

Dynamics

10.1364/qels.2012.qf1g.6

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Light bullets in waveguide arrays: spacetime-coupling, spectral symmetry breaking and superluminal decay [Invited]

Optics Express (2011)

Falk Eilenberger Stefano Minardi Alexander Szameit U. Röpke Jens Kobelke

We investigate the effects of the space-time coupling (STC) on the nonlinear formation and propagation of Light Bullets, spatiotemporal solitons in which dispersion and diffraction along all dimensions are balanced by nonlinearity, through periodic media with a weak transverse modulation of the refractive index, i.e. waveguide arrays. The STC arises from wavelength dependence of the strength of inter-waveguide coupling and can be tuned by variation of the array geometry. We show experimentally and numerically that the STC breaks the spectral symmetry of Light Bullets to a considerable degree and modifies their group velocity, leading to superluminal propagation when the Light Bullets decay.

Superluminal motion

Slow Light

Waveguide

Group velocity

Ray

10.1364/oe.19.023171

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Citations (35)

Nonlinear, discrete-continuous propagation of ultrashort pulses in 2-dimensional, periodic fibre arrays

Falk Eilenberger Thomas Pertsch Stefan Nolte F. Lederer U. Röpke

We investigate the propagation of ultrashort pulses in 2D fibre arrays both numerically and experimentally. The nonlinearity suppresses discrete diffraction and dispersion, leading to spatiotemporal contraction, as well as pulse breaking and supercontinuum (SC) generation.

Supercontinuum

Ultrafast optics

10.1109/oeccacoft.2008.4610496

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Sensor Fibres and a New Concept for Distributed Temperature and Strain Sensing by Brillouin Scattering

Optical Fiber Sensors (1996)

Dieter Garus E. Geinitz Torsten Gogolla S. Jetschke Katerina Krebber

For distributed measurements of strain and temperature with high spatial resolution we prepared and investigated silica fibres with various dopants and propose a new sensor concept based on a frequency domain approach and Brillouin scattering.

Brillouin zone

Distributed Acoustic Sensing

Strain (injury)

10.1364/ofs.1996.th328

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Citations (3)

Discrete-continuous spatio-temporal light localization in nonlinear fiber arrays

Falk Eilenberger Alexander Szameit Thomas Pertsch Stefan Nolte F. Lederer

In this paper, we present major improvements in nonlinear field, since we have been able to fabricate homogeneous fiber bundles, which allow us to study the clean spatial nonlinear dynamics of light. Furthermore, it becomes possible to observe the combined effects of temporal and spatial dynamics.

Dynamics

10.1109/cleoe-iqec.2007.4386852

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Three-Dimensional Light Bullets in Arrays of Waveguides

Physical Review Letters (2010)

Stefano Minardi Falk Eilenberger Yaroslav V. Kartashov Alexander Szameit U. Röpke

We report the first experimental observation of three-dimensional light bullets, excited by femtosecond pulses in a system featuring quasi-instantaneous cubic nonlinearity and a periodic, transversally modulated refractive index. Stringent evidence of the excitation of light bullets is based on time-gated images and spectra which perfectly match our numerical simulations. Furthermore, we reveal a novel evolution mechanism forcing the light bullets to follow varying dispersion or diffraction conditions, until they leave their existence range and decay.

10.1103/physrevlett.105.263901

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Citations (229)

Investigation of fiber laser pulses by a fiber-Bragg-grating (FBG) spectrum analyzer

S. Jetschke V. Hugemann U. Röpke G. Shtyterman v. Langeweyde K. Mori

We prepared two fiber-Bragg-gratings (FBG)-arrays for the wavelength range 1074 - 1100 nm, both with a spectral width of 0.1 nm and a reflectivity of about 1% of the individual gratings so that pulses are investigated from an Yb fiber laser, Q-switched by an acousto-optical modulator with a repetition rate of 2.6 kHz. Using FBG-array the development of high spikes over some roundtrips in the fiber laser resonator was observed and spectrally analyzed.

Fiber Bragg Grating

PHOSFOS

10.1109/cleoe.2003.1313705

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Preparation and application of functionalized photonic crystal fibres

physica status solidi (a) (2007)

Hartmut Bartelt J. Kirchhof J. Kobelke Kay Schuster Anka Schwuchow

The concept of microstructured and photonic band gap fibres opens a wide range of flexibility to introduce specific functionality in fibre light guiding properties and to adapt optical fibres to specific applications. In addition to flexible structural parameters, the use of specific material properties further increases the design freedom in optical fibres. In order to demonstrate the wide functional capabilities of such fibres, we have investigated different index guiding and photonic band gap fibres made from pure and modified silica and from non-silica materials. The main interest in the use of different materials than the well-known high-purity silica is to utilize special optical properties such as high nonlinearity, specific dispersion or extended infrared transmission windows. A main challenge for such unconventional materials is to transfer the excellent properties of silica-based photonic crystal fibres, like low spectral loss or good durability, to the modified or non-silica materials. The preparation of modified silica-based photonic crystal fibres was implemented by the MCVD doping process or by the use of high-melting lanthanium or lead silicate special glasses. Highly germanium-doped silica rods were used for the preparation of index guiding and for band gap guiding fibres. The prepared fibres were investigated in their mode propagation properties and compared to model calculations. Application examples are presented for spectral fibre sensing and for supercontinuum generation. (© 2007 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)

Supercontinuum

Subwavelength-diameter optical fibre

10.1002/pssa.200776406

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Citations (6)

Characterization of photodarkening processes in Yb doped fibers

Proceedings of SPIE, the International Society for Optical Engineering/Proceedings of SPIE (2009)

S. Jetschke U. Röpke Sonja Unger J. Kirchhof

The time-dependence of photodarkening (PD) in Yb-doped fibers is commonly fitted with a stretched exponential function to determine typical parameters of the process. But, the experimental conditions to obtain consistent results from the comparison of PD for different pump powers, various concentrations of the dopants, or fibers from different manufacturers are not adequately regarded up to now. We discuss the requirements concerning the measurement method as well as the impact of the initial state of the fiber under test. Further on, the experimental results of PD characteristics are discussed in the framework of a kinetic model of the observed processes. The discussion of the measurable PD loss is expanded by introducing the concept of the "PD state" that defines the PD loss as a weighted mean and takes effect on the further evolution of the process. In this way, the basis of fiber characterization and the understanding of the PD kinetics will be improved.

Photodarkening

Characterization

10.1117/12.807544

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Citations (21)

Spatio-temporal light propagation in complex two-dimensional waveguide lattices

Thomas Pertsch Falk Eilenberger Stefano Minardi Stefan Nolte F. Lederer

We investigate the dynamics of spatio-temporal nonlinear localization in arrays of evanescently coupled silica fiber arrays. In contrast to continuous systems the formation of stable light bullets becomes possible.

Waveguide

Dynamics

10.1109/leoswt.2009.4771708

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