PbS nanoparticles integrated microfiber device for Q-switched fiber laser

We experimentally demonstrated the all-fiber erbium-doped Q-switched fiber laser based on the evanescent field interaction with lead sulfide (PbS) as saturable absorber (SA). The SA was fabricated by depositing the dispersion of PbS nanoparticles onto the taper of the microfiber with a diameter of similar to 10 mu m. The intensity-dependent nonlinear optical absorption of SA was investigated, and its saturation intensity and modulation depth were similar to 3 MW/cm(2) and similar to 30.9 %, respectively. By incorporating the SA into the erbium-doped fiber laser (EDFL), stable Q-switched pulse at the central wavelength of 1558.68 nm can be obtained when the pump power was increased from 30 mW to 220 mW. The repetition rate frequency was increased from 17.21 kHz to 71.72 kHz, meanwhile, the pulse duration exhibited a decreasing trend from 10.67 mu s to 2.74 mu s and the signal-to-noise ratio was 48.31 dB. The maximum pulse energy was 53.24 nJ when pump power at 200 mw. On account of the results of the work, the PbS nanoparticles demonstrated a potential application value as an SA for fiber laser.