Tellurite glasses are promising upconversion optical and laser materials. The upconversion efficiency is strongly influenced by maximum phonon energy of the host, tellurite glasses have lower phonon energy than many common oxide glasses. The characteristic glass transition temperature T_g and crystallization onset T_x, differential scaning calorimetry (DSC) is studied. Glassy structure is verified by XRD. Study of visible absorption spectra and upconversion spectra of rare earth ion doped Bismuth tellurite glasses designate it as futuristic photonic material.