An optical waveguide includes a clad of clad glass and a core of core glass. The clad glass includes gallium, lanthanum, and sulfur. The clad glass may include gallium sulfide and lanthanum oxide. The clad glass may also include lanthanum fluoride. The core glass includes gallium, lanthanum, sulfur, oxygen, and fluorine. The core glass may include gallium sulfide, lanthanum oxide, and lanthanum fluoride. An optical fiber perform is also disclosed.