Observation of Spatio-temporal Instability of Femtosecond Pulses in Normal Dispersion Multimode Graded-Index Fiber

Abstract

We study the spatio-temporal instability generated by a universal unstable attractor in normal dispersion graded-index multimode fiber (GRIN MMF) for femtosecond pulses. Our results present the generation of geometric parametric instability (GPI) sidebands with ultrashort input pulse for the first time. Observed GPI sidebands are 91 THz detuned from the pump wavelength, 800 nm. Detailed analysis carried out numerically by employing coupled-mode pulse propagation model including optical shock and Raman nonlinearity terms. A simplified theoretical model and numerically calculated spectra are well-aligned with experimental results. For input pulses of 200-fs duration, formation and evolution of GPI are shown in both spatial and temporal domains. The spatial intensity distribution of the total field and GPI sidebands are calculated. Numerically and experimentally obtained beam shapes of first GPI features a Gaussian-like beam profile. Our numerical results verify the unique feature of GPI and generated sidebands preserve their inherited spatial intensity profile from the input pulse for different propagation distances particularly for focused and spread the total field inside the GRIN MMF.

arXiv comment6 pages, 6 figures

References in corpus (5)

• Spatial beam self-cleaning in multimode fiber
• Optical solitons in graded-index multimode fiber
• Observation of geometric parametric instability induced by the periodic spatial self-imaging of multimode waves
• Self-organized instability in graded-index multimode fibres
• Spatiotemporal Characterization of Supercontinuum Extending from the Visible to the Mid-Infrared in Multimode Graded-Index Optical Fiber

Cited by in corpus (8)

• Multimode Nonlinear Fiber Optics: Massively Parallel Numerical Solver, Tutorial and Outlook
• Scalable Optical Learning Operator
• Spatiotemporal self-similar fiber laser
• Spatiotemporal mode-locking in lasers with large modal dispersion
• All-fiber all-normal-dispersion femtosecond laser with nonlinear multimodal interference based saturable absorber
• Controlling spatiotemporal nonlinearities in multimode fibers with deep neural networks
• High power high repetition rate supercontinuum generation in graded-index multimode fibers
• Spatiotemporal solitons in dispersion-managed multimode fibers