Christensen Simon L, Michieletto Mattia, Johansen Mette M, Maack Martin D, Lægsgaard Jesper
Opt Lett. 2021 Nov 15;46(22):5755-5758. doi: 10.1364/OL.444158.
We report a novel, to the best of our knowledge, analysis of high power rod fiber amplifiers by monitoring the cross-polarization of the output. Spatially and temporally resolved imaging of co- and cross-polarizations at high power amplification reveals dynamic eigenmode behavior of the rod fiber. The dynamic of the eigenmodes is caused by the moving refractive index grating written by the modal interference pattern of transverse mode instability and is the first direct observation of this refractive index grating, to our knowledge.
