Portal de Periódicos da CAPES

Erbium-activated monolithic silica xerogels and silica-titania planar waveguides: optical and spectroscopic characterization

2001; SPIE; Volume: 4282; Linguagem: Inglês

10.1117/12.424777

1996-756X

L. Zampedri, C. Tosello, Flavio Rossi, S. Ronchin, Raffaella Rolli, M. Montagna, Alessandro Chiasera, Giancarlo C. Righini, S. Pelli, A. Monteil, Stéphane Chaussedent, C. Bernard, C. Duverger, Maurizio Ferrari, Cristina Armellini,

Silicon Nanostructures and Photoluminescence

Recent results obtained for Er 2 O 3 -SiO 2 monolithic xerogels and erbium activated SiO 2 -TiO 2 planar waveguides are presented. Monolithic erbium-activated silica xerogels with erbium content ranging from 0 up to 40000 ppm were prepared by the sol-gel technique. Samples were densified by thermal treatment in air at 950 degrees C for 120 hours. The densification degree and the relative content of hydroxyl groups were studied by NIR absorption and Raman spectroscopies. Emission at 1.5 micrometers , characteristic of the 4 I 13/2 yields 4 I 15/2 transition of Er 3+ ions, was observed at room temperature for all monolithic samples upon continuous wave excitation at 980 nm. For the 5000 Er/Si ppm doped xerogel, an intense photoluminescence was observed with a lifetime of 8 ms for the metastable 4 I 13/2 level. Passive and erbium-activated SiO 2 -TiO 2 planar waveguides, monomode at 632.8 nm, were prepared by a dip-coating technique. Some parameters such as H 2 O content, intermediate and final thermal treatments, and the molar ratio TiO 2 /SiO 2 were modified during the preparation of the solution in order to minimize the final content of residual hydroxyl groups and the phase separation between silica and titania. Raman spectroscopy was used to check the structural properties of the waveguides. A lifetime of 7 ms was measured for the metastable 4 I 13/2 level in a 93SiO 2 -7TiO 2 planar waveguide activated by 10000 ppm Er/(Si + Ti). The best value of the attenuation coefficient was of 0.5 dB/cm at 632.8 nm.