Phase-locking and periodic evolution of solitons in passively mode-locked fiber lasers with slow saturable absorber

Passively mode-locked fiber lasers [1-6] are a unique source of solitons for telecommunications. Ultra-short pulse generation in laser systems is based on a variety of schemes including figure of eight fiber laser design [1], fast saturable absorber [3], coupled cavity [5], additive pulse mode-locking [6] and nonlinear polarization rotation [7,8]. The use of a semiconductor mirror-saturable absorber has been suggested for a passively mode-locked soliton laser [9] and its experimental verification has been reported in [10].