Spatio-Temporal Self-Focusing in Femtosecond Pulse Transmission Through Multimode Optical Fibers

We numerically investigate ultra-short pulse propagation in multimode optical fibers with launch peak powers approaching the critical power for self-focusing using a generalized multimode nonlinear Schrödinger equation approach. Nonlinear spatial and temporal effects combined with fiber dispersion govern pulse compression in space and time which can result in damage-inducing intensity levels. Here we identify pulse parameters for which damage is avoided and high-power delivery through optical fiber is possible near the fiber zero-dispersion wavelength.