Period-doubling of multiple solitons in a passively mode-locked fiber laser

We report on the experimental observation of period-doubling of randomly distributed multiple solitons in a passively mode-locked fiber laser. We show that after a period-doubling bifurcation, the period of each soliton in the cavity becomes doubled. However, the intensity variation of the solitons is not necessarily synchronized, indicating that their period-doubling is unrelated. Numerical simulations verified the experimental observations. (C) 2007 Elsevier B.V. All rights reserved.