Tunable passively Q-switched ytterbium-doped fiber laser using MoWS2/rGO nanocomposite saturable absorber

We demonstrated a tunable Q-switched ytterbium-doped fiber laser (YDFL) using MoWS2/rGO nanocomposite as passive saturable absorber. Further, the Mo1-xWS2/rGO nanosheets, with x proportion of 0.2, are synthesized using hydrothermal exfoliation technique. The proposed nanocomposite-PVA based thin film is fabricated by mixing the MoWS2/rGO nanosheets with polyvinyl alcohol (PVA). The fabricated thin film is sandwiched between two fiber ferrules to realize the proposed saturable absorber (SA). Further, the proposed MoWS2/rGO-PVA based thin film SA exhibits a fast relaxation time and a high damage threshold which are suitable to realize a Q-switched pulsed laser with a tunable wavelength range of 10 nm that extends from 1028 nm to 1038 nm. For the highest pump power of 267.4 mW, the generated Q-switched pulses exhibit a narrow pulse width of 1.22 vs, the pulse repetition rate of 90.4 kHz, the highest pulse energy of 2.13 nJ and its corresponding average power of 0.193 mW. To the best of author's knowledge, this is the first realization of a tunable Q-switching fiber laser in a 1 pin wavelength using MoWS2/rGO nanocomposite saturable absorber. (C) 2018 Association of Polish Electrical Engineers (SEP). Published by Elsevier B.V. All rights reserved.