Leventoux Y, Granger G, Krupa K, Mansuryan T, Fabert M, Tonello A, Wabnitz S, Couderc V, Février S
Opt Lett. 2021 Aug 1;46(15):3717-3720. doi: 10.1364/OL.428623.
We present a new, to the best of our knowledge, spatial-spectral mapping technique permitting measurement of the beam intensity at the output of a graded-index multimode fiber (GIMF) with sub-nanometric spectral resolution. We apply this method to visualize the fine structure of the beam shape of a sideband generated at 1870 nm by geometric parametric instability (GPI) in a GIMF. After spatial-spectral characterization, we amplify the GPI sideband with a thulium-doped fiber amplifier to obtain a microjoule-scale picosecond pump whose spectrum is finally broadened in a segment of optical fiber to achieve a supercontinuum ranging from 1.7 up to 3.4 µm.
