Far-detuned cascaded intermodal four-wave mixing in a multimode fiber

We demonstrate far-detuned parametric frequency conversion
processes in a few mode graded-index optical fibers
pumped by a Q-switched picosecond laser at 1064 nm.
Through a detailed analytical and numerical analysis, we
show that the multiple sidebands are generated through a
complex cascaded process involving inter-modal four-wave
mixing. The resulting parametric wavelength detuning
spans in the visible down to 405 nm and in the nearinfrared
up to 1355 nm.