L-band compact Q-switched fiber laser based on a thulium-doped fiber saturable absorber

In this paper, a compact and stable Q-switched erbium-doped fiber laser operating at around 1600 nm by employing a segment of 1-cm thulium-doped fiber saturable absorber (TDF-SA) is proposed. When the pump power is adjusted between 28 and 71 mW, the Q-switched operation can be maintained stably, and the output power increases from 74 µW to 2.6 mW. Furthermore, the peak power clamping effect is also observed when the pump power exceeds 60 mW. The structure of the cavity is greatly simplified by using all-optical and hybrid fiber components, which contributes to its long-term stability. Our results prove that the TDF can be a promising SA for all-fiber Q-switched pulses generation in the L-band.