Passively Q-switched and femtosecond mode-locked erbium-doped fiber laser based on a 2D palladium disulfide (PdS₂) saturable absorber

Stable Q-switched and mode-locked erbium-doped fiber lasers (EDFLs) are first demonstrated by using the novel layered palladium disulfide (PdS₂), a new member of group 10 transition metal dichalcogenides (TMDs)-based saturable absorbers (SAs). Self-started Q-switched operation at 1567 nm was achieved with a threshold pump power of 50.6 mW. The modulation ranges of pulse duration and repetition rate were characterized as 12.6–4.5 μs and 17.2–26.0 kHz, respectively. Meanwhile, a mode-locked EDFL was also obtained with a pump power threshold of 106.4 mW. The achieved pulse duration is 803 fs, corresponding to a center wavelength of 1565.8 nm and 4.48 nm 3 dB bandwidth. To the best of our knowledge, the achieved pulse duration of the mode-locked EDFL in this work is the narrowest compared with all other group 10 TMD SA-based lasers.