Passively Q-switched ytterbium-doped fiber laser based on a SWCNT@AFI saturable absorber

An all-fiber passively Q-switched ytterbium-doped fiber laser (YDFL) was successfully achieved by using a single-walled carbon nanotube (SWCNT) as a saturable absorber (SA). The SWCNT was fabricated by pyrolyzing tripropylamine in the one-dimensional channel of zeolite single crystal (ZnAPO-5, framework type code: AFI). Zn 2+ metal cations were doped to promote the filling density and quality of the SWCNT. Subsequently, by incorporating the SA into an YDFL ring cavity, a stable Q-switched pulse train at 1039.4 nm with a repetition rate of 54.28 kHz was obtained when the pump power elevated to the starting threshold of 245 mW. It proved that this SWCNT@AFI SA can be used as an effective passively Q-switched for operation at 1.0 µm region.