We demonstrate a stable passive Q-switched fiber laser operating at 1560 nm. To realize pulsing generation, a piece of rose gold as a saturable absorber. The self-started Q-switching operation presence from 35 mW and stable until 142 mW pump power. By increasing the pump power to maximum level, generated pulse train has a maximum repetition rate of 89.89 kHz and short pulse width of 2.64 μs with a pulse energy of 103.08 nJ. The maximum output power is 8.56 mW. The obtained pulse is stable with a signal-to-noise ratio of 69 dB at 35 mW pump level.
A multiwavelength Q-switched pulse operation obtained directly using a Tm-doped fiber laser and employing gold nanoparticles (GNPs) as a saturable absorber (SA material) is reported. The GNPs SA exhibits a modulation depth of 5.4% and a nonsaturable loss of 21.3%. Due to the saturable absorption and the high nonlinearity, dual-wavelength and triple-wavelength Q-switched pulse operations are obtained at pump power levels of 200 and 500 mW. To the best of our knowledge, this is the first ever reported use of GNPs as SA in multiwavelength Q-switched lasing generation.