Abstract
Graphene is the thinnest material in the world with the lowest electrical resistance at room temperature among others. It is highly transparent and a good conductor. Graphene is not only used as new electronic materials but also recognized as novel optoelectronic devices, such as solar cells, transparent touch screens, and saturable absorber (SA). In this chapter, a stable optical pulse generation of graphene-based SA in ultra fast fiber laser system is investigated. Two different fabrica tion processes of graphene samples are reported, which are chemical vapor deposition (CVD) and graphene-mediated SA employing different nano-dispersants. For monolayer graphene grown by CVD, linear and non linear optical properties of different stacking of atomic-layers graphene-based SA are investigated and compared. Same optical properties are also performed on dispersed few layers of graphene samples prepared by two different dispersants including fluorinated MICA clay and poly(oxyethylene)-segmented imide (POEM). Pulse duration of mode-locked fiber lasers (MLFLs) can be controlled through the modula tion depth of SA by optimal selection of the number of layers of stacking of monolayer graphene SA. MLFLs with dispersed few layers of graphene SA reveal shortened pulsewidth and enhanced modulation depth as the thickness and concentration product (TCP) of dispersed layer-graphene SAs increases.