Nanosecond passively Q-switched fibre laser using a NiS₂ based saturable absorber

Q-switched pulse laser generation is successfully demonstrated in both Erbium-doped fibre laser (EDFL) and Thulium-doped fibre laser (TDFL) cavities by employing Nickel disulfide (NiS₂) as a saturable absorber (SA). Q-switched pulse laser operation at 1.55 μm and 2.0 μm is obtained at low pump power levels of 37 mW and 48 mW, respectively. For the EDFL, stable passively Q-switched laser output at a wavelength of 1561.86 nm is achieved, with a minimum pulse duration of 237 ns and a repetition rate of 243.9 kHz. For the TDFL, the centre wavelength of the laser output is 1915.5 nm, with a minimum pulse duration of 505 ns and a repetition rate of 214.68 kHz. NiS₂ is used as SA for Q-switched laser generation over a broadband wavelength for the first time.