Improved Laser Damage Threshold of In₂Se₃ Saturable Absorber by PVD for High-Power Mode-Locked Er-Doped Fiber Laser

Abstract

In this study, a double-end pumped high-power passively mode-locked erbium-doped fiber laser (EDFL) was realized by employing a few-layered In2Se3 flakes as a saturable absorber (SA). Herein, the uniform large-scale In2Se3 flakes were synthesized by the physical vapor deposition (PVD) method. The PVD-In2Se3 SA exhibited a remarkable damage threshold of higher than 24 mJ/cm2. Meanwhile, the PVD-In2Se3 SA had a modulation depth and saturable intensity of 18.75% and 6.8 MW/cm2, respectively. Based on the In2Se3 SA, the stable bright pulses emitting at 1559.4 nm with an average output power/pulse energy/pulse duration of 122.4 mW/5.8 nJ/14.4 ns were obtained successfully. To our knowledge, 122.4 mW was the new major breakthrough of mode-locked Er-doped fiber lasers. In addition, this is the first demonstration of the dark-bright pulse pair generation based on In2Se3 SA. The maximum average output power of the dark-bright pulse reached 121.2 mW, which also showed significant enhancement in comparison with previous works. Our excellent experiment results fully prove the superiority of our experimental design scheme and indicate that the PVD-In2Se3 could operate as a promising highly-nonlinear photonic material for a high-power fiber laser.

Keywords

• nonlinear optical materials
• indium selenide
• physical vapor deposition
• mode-locked fiber lasers
• saturable absorber