Noise-like pulse in a gain-guided soliton fiber laser.

We report on the operation of a passively mode-locked fiber ring laser made of purely positive dispersion fibers and mode-locked by using the nonlinear polarization rotation technique. It was experimentally found that apart from the gain-guided soliton operation the laser can also emit a kind of noise-like pulse. We show numerically that the noise-like pulse emission is caused by the peak power clamping effect of the laser cavity on the gain-guided soliton.