Active glass fiber derived via levitation melting of a rare-earth titano-niobate

Containerless melting techniques enable the formation of glasses comprising only rare-earth and transition metal oxides, without any traditional network formers. Until now, such glasses have been limited to length scales of a few millimeters for optical interaction. In this work, a niobate glass is drawn to fiber with diameters of sub-50 μm and lengths of tens of centimeters directly from an undercooled melt in an aerodynamic levitation furnace. A Yb-doped variant is investigated in which waveguiding and gain are demonstrated. Total parasitic losses are estimated to be 1.56 dB/cm, most likely dominated by the unclad nature of the fiber. Unique properties of glasses accessible with levitation melting and applications that can be enabled by the fiberization of these materials are discussed.