Experimental observation of Kerr beam self-cleaning in graded-index multimode fiber from higher-order mode to fundamental mode

Hundred-watt level all-fiber visible supercontinuum generation from a graded-index multimode fiber

“…The near-field beam profile deteriorates slightly as the wavelength decreases, and resulting from that, more high-order modes are excited in the GRIN MMF at the shorter wavelength [23] . Overall, these differences of beam profile are not great because the Kerr selfcleaning effect existing in the GRIN MMF will shorten these differences by converting more energy from the high-order modes to the fundamental modes [9][10][11] . Figure 4(b) plots the SC output power varying with the pump laser power, and the results show that the conversion efficiency of the pump laser to SC is about 47%.…”

“…In comparison with the step-index MMF, the graded-index multimode fiber (GRIN MMF) has attracted much attention due to its unique properties. First, the GRIN MMF has a lower Kerr self-cleaning threshold because its periodic index gratings caused by strong periodic oscillation will convert more energy from the higher-order modes to the fundamental mode [9][10][11] . In terms of SC generation, the combined action of the Kerr effect and the Raman effect achieves a bellshaped beam output in the GRIN MMF [12] .…”

Working with Multimode Fibers using ps and fs Pulses

“…It is observed that number of Raman peaks reduce when the pump is launched in LP02 mode. The spectral peaks location on the blue-side of the pump (IMFWM) re-mains invariant except the spectral power level as compared to the LP01 for same average input pump power [5]. This suggests that it might be possible to achieve a Raman free system in near-IR range by launching higher-order spatial modes which is currently under investigation.…”