Explanation of stimulated Raman scattering in high power fiber systems

We present investigations on the seed source dependence of stimulated Raman scattering (SRS) created in a high power fiber amplifier. It is shown that fiber oscillators are much worse in terms of SRS than other seed sources. The longitudinal mode composition was found to be of less importance. We reinforce the experimental observations by a numerical investigation, which shows that temporal power variations on the ps-scale and their propagation along the fiber are crucial for the SRS creation in high-power fiber systems, extending the well-known but simplified SRS threshold description.