Performance of Q-Switched Fiber Laser Using Optically Deposited Reduced Graphene Oxide as Saturable Absorber
Yuenkiat Yap, Wu Yi Chong, S. A. Razgaleh, Nay Ming Huang, Chinkhai Ong, H. Ahmad
Abstract
Graphene is one of the most attractive two-dimensional nanomaterials widely used as saturable absorber for pulsing laser, owing to its unique non-linear optical responses. However, fabrication and integration of graphene saturable absorber into a laser cavity involves complex processes and procedures. Mass production of graphene-based saturable absorbers requires simplification of the fabrication process with minimum material wastage. Reduced graphene oxide, a functionalized graphene, is found to have saturable absorption property as well. Comparatively, it is easier and more cost-effective to produce. On the other hand, optical deposition is a saturable absorber deposition technique that maximizes material utilization. In this work, commercially available reduced graphene oxide in N-methyl-2-pyrrolidone was used to fabricate a saturable absorber device via optical deposition, due to its simplicity and high efficacy. Optical pulse generation via Q-switching were successfully demonstrated with the optically deposited rGO-SA incorporated into a ring erbium-doped fiber laser. Pulse repetition rate of up to ~85.0 kHz and pulse durations as short as ~2.0 μs were achieved. Its performance as a saturable absorber in a Q-switched fiber laser is then compared with previous works. Comparatively, optically deposited rGO has a much lower Q-switched threshold and holds huge potential for mass production with maximum material utilization.