Novel photonic glasses for future amplifiers

摘要

The status of glass-based photonics materials research for practical functional devices in future optical networks is presented. New candidates for metal-doped broadband gain media and fibre Raman gain media are presented. Bi-doped lithium aluminosilicate glasses have been comprehensively investigated as candidate new broadband band gain media. It was found that the peak wavelength and width of the emission from Bi-doped lithium aluminosilicate glasses can be controlled by the excitation wavelength. The emission spectrum had the broadest full width of half maximum (FWHM) of more than 500 nm under the 900 nm excitation. The emission covered a spectral range from 920 nm to wavelengths over 2000 nm. The emission bandwidth exceeded 1000 nm. The lifetime was almost independent of temperature up to 350 K, indicating that emission from Bi-doped lithium aluminosilicate glass has strong resistance to thermal quenching. The quantum efficiency of the emission was 11% when the glass was excited at 974 nm. TeO2-BaO-SrO-Nb2O5 (TBSN) glass system containing WO3 and P2O5 was systematically studied as new fibre Raman gain media. TBSN glass doped with WO3 and P2O5 showed high stability against crystallisation. Raman bands due to WO4 and PO4 tetrahedra were seen and these broadened the Raman spectrum of the glass system. The Raman gain coefficient and bandwidth of the TBSN tellurite glass have been tailored by systematically adding WO3 and P2O5. The glass system showed the broadest gain bandwidth so far achieved in tellurite glasses while maintaining higher gain coefficients. The gain bandwidths of these glasses were more than twice that of a conventional tellurite-based glass and 70% larger than that of silica glass. These glasses are promising candidates for photonics devices in future photonic systems.