We demonstrate that two kinds of 2D nanomaterials are employed as saturable absorbers to realize infrared pulsed fiber lasers at 1.5 µm and 3 µm, respectively. Mode-locked optical pulses are achieved at 1.5 µm erbium-doped fiber lasers by using multilayer molybdenum disulfide (MoS2). In addition, Q-switched fiber lasers are realized at 3 µm region by using topological insulator:Bi2Te3. Experimental proofs are provided. Our work reveals that 2D nanomaterials like MoS2 and TI: Bi2Te3 are absolutely a class of promising and reliable saturable absorbers for optical pulse generation at infrared waveband.