High-performance passively Q-switched fiber laser based on CuFeO2/SiO2 as saturable absorber

In this paper, we report the optical properties and applications of the CuFeO2 (CFO)/SiO2 novel saturable absorber (SA) by the sol-gel method. The measured results show that our SA's modulation depth, unsaturated loss and damage threshold are 10.9%, 10.1% and 5121 mJ/cm2, respectively. High-quality passively Q -switched fiber laser output at 1.5 & mu;m was successfully achieved using CFO/SiO2 SA. Due to the high damage threshold and low insertion loss of the SA, the maximum output power of the laser are 59.6 mW, the optical conversion efficiency is 6.4%, much higher than other reports, corresponding to an output pulse' peak power and single pulse energy of up to 723.98 mW and 307.7 nJ, and the signal-to-noise ratio of 74 dB indicating its stability. The results indicate that the CFO/SiO2 SA prepared by the sol-gel method provides a new opportunity to develop high-performance SA and high-power passive Q-switched fiber lasers.