High power Q-Switched thulium doped fibre laser using carbon nanotube polymer composite saturable absorber

Abstract

We have proposed and demonstrated a Q-switched Thulium doped fibre laser (TDFL) with a Yin-Yang all-fibre cavity scheme based on a combination of nonlinear optical loop mirror (NOLM) and nonlinear amplified loop mirror (NALM). Unidirectional lasing operation has been achieved without any intracavity isolator. By using a carbon nanotube polymer composite based saturable absorber (SA), we demonstrated the laser output power of ∼197 mW and pulse energy of 1.7 μJ. To the best of our knowledge, this is the highest output power from a nanotube polymer composite SA based Q-switched Thulium doped fibre laser.