Relative Intensity Noise Characterization of Supercontinuum Generation in Multimode Fibers

Multimode fibers (MMFs) have recently attracted significant attention due to their high-power handling capability [1] and beam self-cleaning dynamics [2] that results in a near single-mode profile at the fiber output. Here, we perform a detailed experimental comparison of wavelength-resolved relative intensity noise (RIN) of all-fiber supercontinuum (SC) generated in multimode step-index and graded-index (GRIN) MMFs and show that the intensity noise of SC in the GRIN fibers is similar to that of SC generated in a single-mode fiber (SMF). 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. Our results open the way to generate high-power high beam quality SC sources.