Jul 23 – 26, 2018
Max Planck Institute for the science of light
Europe/Berlin timezone

Spatiotemporal pulse shaping in multimode nonlinear optical fibers

Jul 25, 2018, 9:00 AM
30m
Seminar room (Max Planck Institute for the science of light)

Seminar room

Max Planck Institute for the science of light

Staudtstraße 2 91058 Erlangen

Speaker

Prof. Stefan Wabnitz (Università degli Studi di Brescia)

Description

Nonlinear multimode optical fibers (MMFs) have recently emerged as easily accessible platform to control complex spatiotemporal beam reshaping phenomena. Light intensity oscillations associated to the self-imaging effect in graded-index (GRIN) MMFs lead, via the Kerr effect, to a dynamic long-period index grating which may phase-match the generation of ultra-broadband sideband series. For relatively short, virtually lossless GRIN fibers, beam self-cleaning activated by the Kerr effect is observed, at lower power thresholds than the Raman beam cleanup. The output highly multimode speckled beam evolves, at high powers, into a high brightness bell-shaped beam sitting on a low-power background of high-order modes. This Kerr beam self-cleaning is shown to be even reinforced in the presence of strong loss or gain, e.g., in a passive or active ytterbium doped MMF, which leads to its possible exploitation in high power multimode fiber laser sources. We shall overview recent experiments, which demonstrate the spatiotemporal pulse break-up and significant temporal compression that accompany the self-cleaning process. At the same time, we shall describe experiments revealing the dependence of the output beam shape and the efficiency of the self-cleaning process on the input beam conditions, such as transverse dimension and incidence angle.

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