Simple Fabrication of Paper-like Graphene Oxide for use as Saturable Absorber in Q-switching of Fiber Laser

The rise of graphene has made its derivatives a much sought-after research in nano-material science. One of which that has attracted substantial interest is graphene oxide. Due to its simple top-down synthesis and bandgap tunability, graphene oxide is suited in optoelectronics and photonics applications. Foil or paper-like graphene oxide possesses excellent mechanical strength especially. In this work, we demonstrated a home-made, paper-like graphene oxide for Q-switching operation in a ring erbium-doped fiber laser. The raw material was synthesized using simplified Hummers' method, and subsequently by simple filtration. The free-standing, orderly stacked material is about 6.5 nm thick, corresponding to about 67 layers of uniform sheets. The paper-like material was then transferred directly to a fiber ferrule and sandwiched between two connectors via a fiber adapter. Q-switched pulses were observed when the pump power of the ring laser was increased to about 68 mW. The Q-switched fiber laser has maximum repetition rate, pulse energy, pulse width and average power of 21.5 kHz, 52 nJ, 3.8 ms and 1.1 mW respectively.