Abstract
We demonstrate a passive Q-switched fiber laser using an erbium-ytterbium-thulium (Er-Yb-Tm) doped fiber. The length of the Er-Yb-Tm co-doped fiber is varied from 0.4 m to 1.4 m to study the effect of this passive gain medium for pulse laser performance. The proposed laser operates in the pulse operation regime within a certain range of pump powers, which is dependent on the length of the Er-Yb-Tm co-doped fiber. A longer fiber employed in the laser cavity results in a higher laser pump power threshold, but a wider pump power range of pulse laser operation. The experimental outcome shows that a 1.0 m Er-Yb-Tm co-doped fiber offers the best performance in this work with a Q-switched pump power threshold of 45.1 mW, the widest pulse energy output range of 0.0439 mu J from 0.0167 mu J to 0.0606 mu J, with the supplementary advantage of 120.7 mW Q-switched laser operating range. This fiber gain medium analysis contributes to the generation of short pulse laser source without employing any chemical materials and complex laser setup.