Enhanced broadband NIR emission in glass ceramic fibers containing Nd ³⁺ /Yb ³⁺ co‐doped YCa ₄ O(BO ₃ ) ₃ disordered nanocrystal

Abstract Demands are increasing for ultrashort pulse laser in industrial applications, where the gain bandwidth of most optical fiber material is not wide enough, and developing a wide bandwidth gain medium is challenging. Glass–ceramic fibers containing Nd 3+ /Yb 3+ co‐doped YCa 4 O(BO 3 ) 3 nanocrystals were fabricated by the molten core method and successive heat treatment. After a careful heat treatment, Nd 3+ /Yb 3+ co‐doped YCa 4 O(BO 3 ) 3 nanocrystals were precipitated in the fiber core. Enhanced broadband near‐infrared (NIR) emission from 850 to 1150 nm (bandwidth: ∼252 nm) was obtained in the glass–ceramic fiber compared to that of precursor fiber. These results suggest that the Nd 3+ /Yb 3+ glass–ceramic fibers are promising for broadband NIR optical amplifications and lasers.