Erbium-Doped Fiber Laser Cavity Manufactured by Femtosecond Laser Line-by-Line Inscription Technique

Beneficial from the development of femtosecond laser direct writing technique, the fabrication of Bragg gratings inside a fiber with low photosensitivity like active fiber becomes possible. In this paper, we fabricate erbium-doped fiber Bragg gratings (EDFBGs) using femtosecond laser line-by-line inscription for the first time, and the pump tuning effect is also experimentally studied. Via inscribing a high reflection FBG (HR-FBG) and an output coupler FBG (OC-FBG) in the same EDF without any splicing points, an integrated fiber oscillator was realized, and a maximum output laser power of about 50 mW at 1.5 µm was demonstrated. Our investigations provide a method to diminish fused splicing points in fiber oscillators and reveal the preliminary characteristics of the integrated EDF oscillator, which is meaningful in high-power fiber lasers and integrated fiber optics