Nearly Perfect Raman Self-Cleaning in Graded-Index Multimode Fibers Using Pearcey-Gaussian Pulses

We propose a temporal manipulation scheme for the inner-mode interactions in graded-index multimode fibers (GRIN-MMF). In this scheme, a so-called Pearcey-Gaussian (PeG) wave packet is constructed for the pulse profile, which allows the manipulation of the self-compressing control by the second- and third-order dispersions. Our simulations show that such linear compressing cooperates with the nonlinear compressing of the Kerr effect when the wavelength is close to the zero-dispersion point of the fiber, which enables the manipulation of the nonlinear energy transfer from the higher modes to the fundamental one. Such cooperation of the linear and nonlinear effects triggers a Stokes soliton in the fundamental mode while the Raman red-shifts in the higher modes are negligible. After the proper filter in the spectrum, a nearly perfect Raman self-cleaning with the energy of the fundamental mode reaching 97.2 % is observed.