Bound soliton pulses with FWHM duration of 326 fs and separation of 938 fs in a passively mode locked fiber laser

Summary form only given. A passively mode locked fiber soliton laser was successfully setup. After adjusting the polarization controllers (PC) carefully, bound soliton pulses with FWHM width of 326 fs and fixed separation of 938 fs were achieved with existence of a strong CW component at the center of the soliton spectrum. Hysteresis of bound soliton operation was also observed. Only under lower pump power, can the number of bound soliton pairs be controlled, and they are destroyed one pair by one pair when pump power is decreased. But multi-bound soliton operation is formed suddenly while increasing pump power, because energy competition exists with CW. We found that the soliton pulse width increased with the transmission fiber length linearly, and the separation between bound solitons increased linearly after 5 m.