Investigations of mode-locked fiber laser based on CVD fabricated graphene saturable absorber

A stable mode-locked fiber laser employing graphene as a saturable absorber is presented. One monolayer graphene can obtain mode-locking when the cavity is around 12m, but when the cavity decreases to 6m, no stable pulses can be formed. In order to solve this problem, cascade of two monolayer graphenes is used and stable mode locked pulses with a frequency of 44.53MHz, a bandwidth of 2.4nm, a pulse width of 43.89ps and an average power of 19.10mW have been directly obtained from the laser. Our results show the atomic-layer graphene may be a promising satrurable absorber for stable pulses formation of fiber laser.