A study was initiated to understand requirements for widening and flattening the gain spectra of tellurite-based glasses for their application as new gain media for photonic devices. For this purpose, two Raman active components, $\mathrm{W}{\mathrm{O}}_3$ and ${\mathrm{P}}_2{\mathrm{O}}_5$ , were added either separately or jointly to a $\mathrm{Te}{\mathrm{O}}_2–\mathrm{Ba}\mathrm{O}–\mathrm{Sr}\mathrm{O}–{\mathrm{Nb}}_2{\mathrm{O}}_5$ (TBSN) glass system, and the Raman spectral evolution in response to this addition was studied. Raman scattering cross sections of the TBSN glasses were increased with an increase in the $\mathrm{W}{\mathrm{O}}_3$ content and decreased with an increase in the ${\mathrm{P}}_2{\mathrm{O}}_5$ content. The Raman intensity and bandwidth increased when $\mathrm{W}{\mathrm{O}}_3$ and ${\mathrm{P}}_2{\mathrm{O}}_5$ were jointly added in TBSN. The bandwidths of the Raman gain coefficient spectra of the present tellurite glasses were more than twice that of a conventional $\mathrm{Te}{\mathrm{O}}_2–{\mathrm{Bi}}_2{\mathrm{O}}_3–\mathrm{Zn}\mathrm{O}–{\mathrm{Na}}_2\mathrm{O}$ glass and 70% larger than that of silica glass. The new glasses are expected to be candidates for ultrabroadband fiber Raman amplifiers.