Mode-locked ytterbium-doped fiber laser based on topological insulator: Bi_2Se_3

We demonstrated an all-normal-dispersion Yb-doped mode-locked fiber laser based on Bi2Se3 topological insulator (TI). Different from previous TI-mode-locked fiber lasers in which TIs were mixed with film-forming agent, we used a special way to paste a well-proportioned pure TI on a fiber end-facet. In this way, the effect of the film-forming agent could be removed, thus the heat deposition was relieved and damage threshold could be improved. The modulation depth of the Bi2Se3 film was measured to be 5.2%. When we used the Bi2Se3 film in the Yb-doped fiber laser, the mode locked pulses with pulse energy of 0.756 nJ, pulse width of 46 ps and the repetition rate of 44.6 MHz were obtained. The maximum average output power was 33.7 mW. When the pump power exceeded 270 mW, the laser can operate in multiple pulse state that six-pulse regime can be realized. This contribution indicates that Bi2Se3 has an attractive optoelectronic property at 1μm waveband.