Passively Q-switched erbium-doped fiber laser utilizing lutetium oxide deposited onto D-shaped fiber as saturable absorber

We managed to produce a stable Q-switched pulse laser operating at 1563 nm using Lutetium (III) oxide (Lu2O3) material as a saturable absorber (SA). The Lu2O3 was deposited onto a D-shaped optical fiber and inserted into an erbium-doped fiber laser (EDFL) cavity for pulse generation. The D-shaped fiber was prepared by polishing wheel technique using rough and fine sandpapers to obtain a smooth surface and thus ensure an efficient light-matter interaction inside the SA. The proposed Q-switched EDFL generated pulses with duration as short as 11.84 mu s at a repetition rate of 19.7 kHz. The Q-switched laser output was stable within the pump power of 68mW-96mW with the corresponding pulse energy and output power of 0.16 mu J-0.18 mu J and 2.76mW-3.49mW respectively. The signal-to-noise ratio was around 46.26 dB, which indicates the stability of the laser. The results show that the proposed Lu2O3 SA based on D-shaped fiber is suitable for realizing a portable Q-switched light source.