Spatiotemporal Turbulence in a Multimode Fiber Laser

We demonstrate the occurrence of spatial mode-cleaning in a normal dispersion regime, provided by graded-dissipation in a multimode fiber. It was found that the contribution of excited "internal soliton modes" in the soliton destabilization process becomes crucial when the dissipative soliton energy scales higher (see the Figure, presenting the contour plot of laser field intensity: the wavelength is of 1.03 mm, the pulse power is of 100 kW, the Gaussian beam size is of 10 mm, the input pulse width is of 150 fs, the propagation length is of 1.5 cm). We consider such a mode-cleaning enforced by spatially graded and spectral dissipation, as a realization of distributed Kerr-lens modelocking in a multimode fiber laser, where the turbulent dynamics can be suppressed by the adjustment of dissipative factors. The proposed photonic devices could provide an efficient tool for metaphorical modeling of strongly localized coherent structures, emerging in nonlinear nonequilibrium dissipative systems, e.g., in a Bose-Einstein condensate in the weakly-dissipative limit.