Passively Q-switched 1.3 μm bismuth doped-fiber laser based on transition metal dichalcogenides saturable absorbers

Abstract

In this work, Q-switched fiber laser has been demonstrated in a bismuth-doped fiber laser (BDFL) system using tungsten ditelluride (WTe2) and tungsten disulfide (WS2) as saturable absorbers (SAs). The solution casting method was used to prepare both WTe2 and WS2 thin films SAs. At the threshold pump power, the generation of Q-switched pulse using WTe2 SA resulted in a pulse width of 10.4μ s and a repetition rate of 21.20 kHz. When the pump power was increased to maximum, the pulse width reduced to 8.0μ s, while the repetition rates increased to 22.46 kHz. Similarly, a Q-switched pulse was generated using WS2 SA, with an initial repetition rate of 18.86 kHz and a pulse width of 14.4μ s. The repetition rate of the pulses then increased to 19.53 kHz and pulse width reduced to 11.2 μs with the increasing pump power. The maximum pulse energy obtained for WTe2 and WS2 SAs was 13.93 nJ and 11.36 nJ, respectively, with a maximum average output power of 0.313 mW (WTe2) and 0.222 mW (WS2). This work uses the transition metal dichalcogenides (TMDs) materials to generate Q-switched pulses in BDFL operating at 1.3 µm region.