Q-switched erbium-doped fiber lasers with ITO thin film saturable absorbers: A comprehensive cavity configuration study

This study presents the utilization of an indium tin oxide (ITO) thin film as a saturable absorber (SA) in various cavity configurations to illustrate a Q-switched erbium-doped fiber laser (EDFL). The system is designed in three distinct configurations, including linear, single-ring, and Figure-8 cavities, by integrating ITO in the setup, which has a modulation depth of 48.04 %. The research findings highlight that the single-ring cavity design has better performance over linear and Figure-8 designs in terms of Q-switched EDFL performance. The advantage of the single-ring cavity design is demonstrated by the higher values of the repetition rate and signal-to-noise ratio, which are 37.60 kHz and 57.45 dB, respectively. Subsequently, this single-ring cavity can be employed in applications of tunable, switchable dual-wavelength systems and optical fiber sensing.