Origin of spontaneous wave mixing processes in multimode GRIN fibers

We show that geometric parametric instability (GPI) in graded-index multimode fibers is strongly influenced by higher-order dispersion. By measuring the output spectrum for different core radii, we distinguish peaks generated by GPI from other coexisting parametric processes using phase-matching arguments and numerical simulations. We highlight for the first time a non-degenerate GPI process involving two pumps at different wavelengths. (C) 2021 Optical Society of America under the terms of the OSA Open Access Publishing Agreement

Automated summary

The study demonstrates that geometric parametric instability (GPI) in graded-index multimode fibers is significantly affected by higher-order dispersion. By measuring output spectra for different core radii and using phase-matching arguments and numerical simulations, the peaks generated by GPI are distinguished from other coexisting parametric processes. Furthermore, a non-degenerate GPI process involving two pumps at different wavelengths is highlighted for the first time.