Conditions of formation of bulk tellurium chalcogenide glasses, containing 70-80 at % Te associated to Ga and Ge are described. The characteristic temperatures are measured: the glass-transition temperature, T-g, is situated in the range 140-185 degrees C and the difference T-x-T-g, where T-x is the onset crystallization temperature, is in the range 76-113 degrees C. Moreover, the optical transmission window is exceptional, ranging from 1.99 mu m in the bandgap up to 28 mu m in the phonon region. Developed within the framework of requirements for the Darwin mission (a search for and study of extrasolar planets), feasibility of infrared optical fibers formed from these glasses is studied. Drawing experiments are conducted with the glass Ga2Ge3Te15, which possesses the maximum T-x-T-g, and a first optical fiber is presented.