Passively Q-switched Erbium-doped fiber lasers by a microfiber-based PbS quantum dot saturable absorber

We demonstrated the passively Q-switched Erbium-doped fiber laser by the microfiber-based PbS quantum dot (QDs) as saturable absorber (SA). Compared with other SA, the microfiber-based PbS QDs had higher thermal damage threshold and tunable spectroscopic properties. We fabricated the microfiber with the diameter of 5.86 μm and the interaction length of 2 mm and the PbS QDs with the peak of absorption spectrum at 1533nm. Finally we have successfully demonstrated the Q-switched fiber laser with the pulse width decreased from 3.68μs to 3.24μs and the repetition rate increased from 93.4 kHz to 101.9 kHz.