Effect of output coupling ratio on performance of Q-switched fiber laser based on MgQ2 organic saturable absorber

This study experimentally investigates an organic 8-Hydroxyquinoline magnesium (MgQ2) thin-film saturable absorber (SA). The MgQ2-SA is prepared using the drop-casting method to create a solid polymer film. The results show that the optical properties of the MgQ2-SA film include a non-saturable absorption of 30 , a saturable absorption of 22.5 , and a saturable intensity of 11.4 MW/cm2. The Q-switched operation using MgQ2-SA film produces pulse widths ranging from 7.45 µs to 1.4 µs, with pulse repetition rates reported from 32 to 135 kHz, particularly in the coupling ratio range of 50 to 10 . Q-switched spectral operations were observed at wavelengths of 1530 nm for 10:90 output coupler (OC). Besides, for 50:50 OC, dual-wavelength spectrum is recorded with peaks at 1557 nm, and 1559 nm wavelengths. The proposed system architecture shows the capability to generate unique pulse characteristics across various wavelengths and different coupling ratios. © 2025