Fe-MOF as a novel saturable-absorber for pulse operation in erbium-doped fiber lasers

This study demonstrated the utilization of an iron metal–organic framework (Fe-MOF) thin film to act as a saturable absorber in a passively Q-switched erbium-doped fiber laser cavity. The Fe-MOF thin film was prepared using the conventional solution method technique and was characterized using XRD, SEM, EDX, and Raman. The integration of Fe-MOF thin film into fiber ferrule yields a stable self-starting Q-switching operation at a pump power of 55.4 mW. Besides at a maximum pump power of 531 mW, emission at 1561.8 nm, minimum pulse duration of 3.9 µs, maximum repetition rate of 91.7 kHz, and a maximum average output power of 10.8 mW was achieved. The measured results further reveal a maximum 53 dB single-to-noise ratio (SNR), signifying good pulse stability. Moreover, we examined a Fe-MOF-SA damage threshold and long-term stability. The optimum stability, excellent threshold, and shorter pulse width highlight the potential of Fe-MOF as a promising saturable absorber (SA) in a passively Q-switched fiber laser. In addition, this study broadened the applications of MOFs in pulse laser technology and introduced a new approach to advancing the field of ultrafast photonics.