Large-energy passively Q-switched Er-doped fiber laser based on CVD-Bi2Se3 as saturable absorber

In our work, Bi2Se3 was successfully used for demonstrating a large-energy passively Q-switched erbium-doped fiber laser. Bi2Se3 nanosheets were fabricated by a catalyst-free chemical vapor deposition method. Based on a pyrolysis tape transfer method, the Bi2Se3 thin film on the SiO2 substrate was transferred to the end of the optical connector for constructing the fiber-integrated saturable absorber. The saturation intensity and modulation depth of the Bi2Se3 saturable absorber were 81.1 MW/cm2 and 15.7%, respectively. A stable Q-switched operation at 1549.99 nm with a maximum average output power of 23.61 mW was achieved. The minimum pulse duration and the largest pulse energy were 1.34 μs and 224.5 nJ, respectively. In comparison with previous works, the single pulse energy (224.5 nJ) obtained in our experiment was improved significantly. Our experimental results fully proved that CVD-Bi2Se3 has good performance in obtaining large energy pulse operations and will promote the applications of 2D CVD-materials in the field of pulse laser.