Q-Switched Fiber Laser Using a Fiber-Tip-Integrated TI Saturable Absorption Mirror

A wideband-tunable Q-switched fiber laser with a high-reflective topological insulator saturable absorber mirror (TISAM) was proposed and experimentally demonstrated. The proposed TISAM is composed of Sb
₂
Te
₃
and gold films deposited over the fiber tip, and it has the advantage of compact size, easy integration over fiber, good stability, and mass production ability. The modulation depth, saturable intensity, and nonsaturable loss of the TISAM at 1550 nm are experimentally tested to be 6.2%, 143 MW/cm
²
, and 4.2%, respectively. By using such TISAM, we obtain laser pulses of ~400 ns in pulse width and kHz in repetition rates over the wavelength range from 1530 to 1570 nm. The experimental results indicate that the Sb
₂
Te
₃
based TISAM have good potentials for Q-switched fiber lasers.