Relative intensity noise characterization of supercontinuum generation in graded-index and step-index multimode fibers.

Multimode fibers have recently attracted significant attention due to their high-power handling capability and beam self-cleaning property that results in a single-mode profile at the fiber output. Here, we perform a detailed experimental comparison of the relative intensity noise (RIN) of all-fiber supercontinuum (SC) generated in multimode step-index (MMF) and graded-index (GRIN) fibers. We also characterize the spatial intensity profile of the SC in different wavelength bands, showing that it is near single mode across the full spectrum.