Passive synchronization between a self-similar pulse and a bound-soliton bunch in a two-color mode-locked fiber laser

We report the first (to our knowledge) experimental observation of passive synchronization between a 1.03 microm self-similar pulse and a 1.56 microm bound-soliton bunch in a two-color mode-locked fiber laser. The self-similar pulse can form an effective potential well of several picoseconds to trap the copropagating bound solitons in the shared-fiber section. Such synchronization mechanism is supported by the experimental evidence of smaller time separation between the bound solitons under synchronization. In addition, the self-similar pulse and bound solitons can still remain locked under the periodic collision of another 1.56 microm unlocked pulse train.