Fluorescence enhancement in broadband Cr-doped fibers fabricated by drawing tower.

The fluorescence enhancement in broadband Cr-doped fibers (CDFs) fabricated by a drawing tower with a redrawn powder-in-tube preform is proposed and demonstrated. The CDFs after heat treatment exhibited Cr⁴⁺ emission enhancement with spectral density of 200 pW/nm, verified by the formation of α-Mg₂SiO₄ nanocrystalline structures in the core of CDFs. The high fluorescence achievement in the CDFs is essential to develop a broadband CDF amplifier for next-generation optical communication systems.