Rare-earth-doped optical amplifiers have a great potential for broadband Wavelength-Division-Multiplexed (WDM) telecommunication by tailoring host glass compositions. In order to design the emission spectra of doped rare-earth ions, it is important to understand the relationship between the local ligand field and various optical properties of specific 4f-levels, such as the radiative transition probability, the nonradiative decay probability, which dominate the spectral line width and quantum efficiency of amplification transitions. For the Er 3 + :1.55 μm transition, the role of the Judd-Ofelt Ω 6 parameters is presented, which is correlated to the Er-ligand bond covalency in glasses. The Tm 3 + : 1.46-μm transition shows quantum efficiency over 90% high enough for the S-band application, in heavy metal oxide glasses with moderate phonon energy and wider spectra than fluorides. A way to improve population inversion by selective energy transfer with codoped lanthanide ions is presented. Finally, the energy level structures and resultant spectral properties of Pr 3 + , Nd 3 + and Dy 3 + ions, 1.3-μm-active ions, are compared. The hypersensitivity of Dy 3 + transitions appears especially in chalcogenide glasses, where the nonradiative loss due to multiphonon decay is also minimized. In conclusion, glass materials have opportunities to vary the radiative cross section, quantum efficiency, and gain flatness, which are important for novel amplifiers in the future DWDM system.
Les telecommunications a large bande basees sur le multiplexage en division de longueur d'onde (WDM) font appel a des amplificateurs optiques dopes avec des terres rares. Le spectre d'emission de ces terres rares peut etre ajuste en modifiant la composition du verre. Il faut pour cela connaitre la relation entre le champ local et les caracteristiques optiques des niveaux concernes, en particulier les probabilites de transition radiative et de desexcitation non radiative, qui determinent la largeur spectrale et le rendement quantique des transitions. Le role du parametre de Judd-Ofeld Ω 6 dans la transition de l'erbium a 1,55 μm est correle a la covalence de la liaison Er-ligande dans le verre. Les transitions du Tm 3 + pour la bande S et celle des ions Pr 3 + , Nd 3 + et Dy 3 + a 1,3 μm sont egalement abordees et discutees. Dans les materiaux vitreux, on peut ainsi faire varier la section efficace radiative, le rendement quantique et la constance du gain, ce qui peut se reveler important pour les nouveaux amplificateurs dans les futurs systemes DWDM.