Design, fabrication and thermal annealing of Nd-doped all-solid anti-resonant silicate fibers for 0.9 μm laser

We report the design, fabrication and characterization of a Nd-doped silicate-glass-based all-solid anti-resonant fiber (Nd-AS-ARF) for 0.9 μm laser. Through the rod-in-tube technique combined with high-temperature drawing, the Nd-AS-ARF was successfully fabricated with a background loss of 0.3 dB/m at 1200 nm. The results of electron probe microanalysis (EPMA) test indicate a significantly diffusion of the Ba element accompanying the fiber drawing process. Additional thermal annealing could further enhance element diffusion, enabling the active regulation of the resonant band towards longer wavelengths. In the 30 cm-long Nd-AS-ARF, the loss at 1.06 μm is 10.5 dB higher than at 0.92 μm, favoring the Nd three-level laser. To the best of our knowledge, this is the first time that a rare-earth doped AS-ARF is fabricated.