Formation of noise-like square-wave pulses in a microfiber based topological insulator fiber laser

摘要

We demonstrated the formation of noise-like square-wave pulses in an Er-doped fiber laser, using a microfiber based topological insulator as a saturated absorber (SA). The SA guaranteed both excellent saturable absorption and high nonlinearity. The pulse width can be increased ranging from 0.985 to 5.503 ns by increasing the pump power from 212 to 284 mW with the polarization state fixed. Moreover, with the adjustment of the polarization controllers in the cavity, the pulse width can be adjusted obviously. Worth mentioning, it was the first time that the noise-like square-wave pulse formed in a microfiber based topological insulator fiber laser.