Q-switched erbium-doped fiber laser using multi-layer graphene based saturable absorber

Abstract

The performance of a stable passive Q-switched Erbium Ytterbium co-doped fiber laser (EYFL) operating at 1532.5 nm is demonstrated using a multi-layer graphene film based saturable absorber. The graphene is synthesized by electrochemical exfoliation of graphite at room temperature in 1% sodium dodecyl sulphate (SDS) aqueous solution. Graphene flakes obtained from the process are mixed with polyethylene oxide (PEO) as the host polymer to produce free standing composite thin film which acts as a passive Q-switcher in the EYFL ring cavity. At 980 nm pump power of 44 mW, the EYFL generates optical pulse train with a repetition rate of 12.33 kHz and pulse width of 9.36 μs. The highest energy of 5.8 nJ and the lowest pulse width of 2.68 μs are achieved at the maximum pump power of 78 mW. Further increase in the pump power is expected to further improve both the pulse energy and pulse width.