We report the fabrication of waveguides using the fiber on glass (FOG) method. Taking advantage of a Thermal Mechanical Analyzer (Shimadzu TMA-50), we were able to produce a new type of waveguide by coupling an erbium doped fiber core onto a planar glass substrate. Both optical fiber core and substrate were fabricated from tellurite glass. Important thermal characteristics of the substrate and fiber like the transition temperature Tg, the temperature for the crystallization onset Tx and the maximum crystallization temperature Tc were determined by Differential Thermal Analysis (DTA). The thermal expansion coefficient of the tellurite glass was determined by Thermal Mechanical Analysis (TMA).