Q-Switched Pulse and Mode-Locked Pulse Generation From a Yb3+-Doped Fiber Laser Based on Bi2Se3

The Q-switched pulse and mode-locked pulse were investigated in an all-normal dispersion Yb-doped fiber laser (YDFL) based on the topological insulators (Tls) with mixing of polyvinyl alcohol (PVA) to produce Bi2Se3/PVA film or deposition on the end facet of fiber to manufacture TI-compatible fiber. Through the dark Bi2Se3/PVA films with large nonsaturable loss, the YDFL was operated in the Q-switched state. The repetition rate and the duration of the Q-switched pulses increased and declined, respectively, with the pump power to show 2.2 mu s duration and 137.8 kHz repetition rate at the highest pump power. Moreover, the mode-locked pulses, with a 16 MHz repetition rate and 380 ps pulsewidth, were generated at high pump power by using the light Bi2Se3 /PVA film. By means of a Bi2Se3 compatible fiber, through optical deposition of the Bi2Se3 nanoplatelets on the end facet of the fiber, the mode-locked YDFL was generated at low-threshold pump power and revealed more stabilized operation state up to two hours.