Nonlinear pulse dynamic in a weak coupled normal dispersion multicore fiber

Linear and non-linear propagation of ultrashort pulses in a seven-core fiber was investigated experimentally and numerically in a normal dispersion regime. We observed non-uniform coupling conditions between different cores that may be the result of a random refractive index deviation. It was characterized by measurements of the power distribution and FROG traces at the output of a multicore fiber. The cores were excited by a spatial light modulator using the weighted Gerchberg-Saxton algorithm to generate phase masks. It allows us to switch-on any combination without manual alignment of the experimental setup. Finally, as the input power increased, a nonlinear coupling was observed between the selected cores, similar to a saturable absorber. So we believe that such a device could be useful for a development of high-power ultrashort fiber lasers and pulse shaping applications.