Multimode solitons in step-index fibers

We experimentally generate multimode solitons in step-index fibers, where nonlinearity compensates for both chromatic and modal dispersion. These solitons are subject to Raman self-frequency shift, and their energy is gradually transfered to the fundamental fiber mode. We compare multimode soliton dynamics in both step-index and graded index fibers, in excellent agreement with numerical predictions.