Mode-locked fiber laser stabilized by semiconductor saturable absorber modulated with the residual pump

Summary form only given. We present an harmonic passively mode-locked fiber laser employing two saturable absorbers - one absorber is responsible for starting up the mode-locking process, while the other is optimized to provide a high modulation index of the cavity loss by optically pumping it above the band-gap. The unique aspect of this work is that the pulse organization is accomplished by modulating the 980-nm light used for both pumping the gain medium and optical modulation of the absorber. We show that this approach can be used for efficient pulse synchronization to an external RF signal and for considerable reduction of the timing jitter. In addition we demonstrate, for what is believed to be the first time, that optimized semiconductor saturable absorber mirror (SESAM) structures can provide modulation depth of the absorption by optical pumping, which is sufficient to initiate active mode-locking.