New phospho-tellurite glasses with optimization of transition temperature and refractive index for hybrid microstructured optical fibers

•Glass-forming region in TeO2–ZnO–Na2O–P2O5 system were investigated.•The refractive index varies from 1.513 to 2.036 by modifying TeO2 and P2O5.•Tg can be adjusted from 265 °C to 376 °C by controlling of ZnO and Na2O contents.•Fibers with special dispersion were designed using phosphor-tellurite glasses.

The glass formation and compositional dependences of glass thermal properties and optical properties were investigated in TeO2–ZnO–Na2O–P2O5 system. The refractive index at 1.55 μm and glass transition temperature varied in a wide range from 1.513 to 2.036 and from 265 °C to 376 °C by controlling of the TeO2/P2O5 and ZnO/Na2O content, respectively. These properties enable phospho-tellurite glasses with large freedom in designing and fabrication of hybrid microstructured optical fiber. The structures of glasses were investigated by Raman spectra to understand their dependence of structure on composition. Using the present glasses, some hybrid microstructured optical fibers with various dispersion profiles were designed.