Fig. 8
From: Accelerated nonlinear interactions in graded-index multimode fibers
Theoretical stability diagram for a locally uniform multimode fiber. a Change in the stability diagram when the fiber radius is reduced from 40 to 10 µm. A reduction in the radius of the multimode fiber shifts the unstable gain regions, thus leading to new spectral lines. b and c are the stability diagrams corresponding to parabolic multimode fibers with core radii of 40 and 10 µm, respectively. In all cases, the input spot-size was chosen to be 1.5 times that of the fundamental mode and the input peak power was assumed to be 180 kW. The parameters α and δ are defined as \(\alpha = \frac{{a_0^2}}{{2{\mathrm{\Delta }}}}\beta _e^2\), \(\delta = \frac{{a_0^2}}{{2{\mathrm{\Delta }}}}\beta _ek_0n_2E_0^2w_0^2\)
