Kerr beam self-cleaning and supercontinuum generation in a graded-index few-mode photonic crystal fiber

Multimode optical fibers (MMFs) are an excellent alternative to single-mode fibers for applications where high power level is required or for investigating spatiotemporal nonlinear wave propagation [1] . Recent experiments have shown that it is possible to achieve a speckleless output beam in MMF through a novel nonlinear effect called Kerr-induced beam self-cleaning (KBSC) [2] . This effect has been observed in a wide variety of MMFs, including standard graded-index (GRIN) MMFs and photonic crystal fibers (PCFs). Here, we report on the observation of low-peak-power KBSC and supercontinuum generation (SCG) in a few-mode PCF with a GRIN core.