Effective cavity dispersion shift induced by nonlinearity in a fiber laser

We report on the experimental observation of high peak power stretched-pulse emission in a dispersion-managed (DM) fiber laser with large positive net cavity dispersion. As stretched pulses are normally observed in DM fiber lasers with around zero cavity dispersion, it suggests that the effective cavity dispersion of a DM fiber laser is not a fixed value but varies with the laser operation conditions. Based on numerical simulations we further show that a stretched pulse could indeed be obtained in our laser under the laser operation condition when a high peak power pulse is formed, suggesting that the effective cavity dispersion shifts with the cavity nonlinearity.