Sc<sub>2</sub>O<sub>3</sub> Thin Film for Q-Switching Application in Erbium-Doped Fiber Laser

This study demonstrates the utilization of a Scandium Oxide (Sc<sub>2</sub>O<sub>3</sub>) film as a passive saturable absorber (SA) for pulse generation within the C-band region in an Erbium-Doped Fiber Laser (EDFL) cavity for possible applications in metrology, sensing, and medical diagnostics. The SA was fabricated using Sc<sub>2</sub>O<sub>3</sub> powder, with polyvinyl alcohol (PVA) employed to form the film. The experimental setup utilized an all-fiber ring cavity configuration. Q-switching was achieved over a range of pump powers from 48.8 mW to 84.8 mW. It is observed that as the pump power increased, the repetition rate rose from 42.3kHz to 82.8 kHz, accompanied by a reduction in pulse width from 5.04 μs to 2.82 μs. At a pump power of 84.8 mW, the system achieved a maximum output power of 6.75 mW and a maximum pulse energy of 81.6 nJ. The EDFL also has a high signal-to-noise ratio (SNR) at the fundamental frequency which is 55.4 dB, highlighting the stability of the Q-switched pulses.