Extended germano-gallate fiber drawing domain: from germanates to gallates optical fibers

Here we report on the production of crystal-free light guiding fibers using a preform-to-fiber approach in the germano-gallate glass system Ga2O3-GeO2-BaO-La2O3-Y2O3 for various contents of gallium to germanium. For glasses in the system Ga2O3-GeO2-BaO-K2O, where surface crystallization precludes fiber drawing from the preform, an open-crucible technique enables the drawing of fiber samples tens of meters long. Cut-back optical attenuation measurements show the extended transmission in the mid-infrared of the produced fibers, up to 2.8 µm with minimum losses of 3.1 dB/m at 1310 nm from unpurified glass. These results show that the germano-gallate glasses represent promising mid-infrared materials over an extended fiber drawing domain.