A family of low-loss high-concentration rare-earth-doped Ga-As-Sb-S chalcogenide glass fibers for mid-infrared laser application

This study presents what we believe to be a novel chalcogenide glass composition, Ga_0.8As_34.2Sb₅S₆₀, as a gain medium for mid-infrared fiber lasers. A systematic investigation was conducted on the thermal stability, absorption, and mid-infrared emission properties of rare-earth (Tm³⁺, Ho³⁺, Dy³⁺, Pr³⁺) -doped glasses. Few-mode double-clad fibers were fabricated, exhibiting a high rare-earth solubility up to 2000 ppmw and record-low optical losses (0.31 dB/m for Ho³⁺ -doped fiber and 0.57 dB/m for Pr³⁺ -doped fiber). Dy³⁺ - and Tm³⁺ -doped fibers also achieved low losses of approximately 1-2 dB/m at present. Combined with the high rare-earth solubility and excellent thermal stability, these fibers demonstrate significant potential for high-performance fiber lasers operating in the 2-5 µm wavelength range.