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Erbium/Ytterbium-activated silica-titania planar and channel waveguides prepared by rf-sputtering

2003; SPIE; Volume: 4990; Linguagem: Inglês

10.1117/12.474774

1996-756X

Alessandro Chiasera, M. Montagna, C. Tosello, Rogéria Rocha Gonçalves, Andrea Chiappini, Maurizio Ferrari, L. Zampedri, S. Pelli, Giancarlo C. Righini, A. Monteil, V. Foglietti, A. Minotti, Rui M. Almeida, Ana C. Marques, Viviane Oliveira Soares,

Advanced Fiber Laser Technologies

SiO 2 -TiO 2 :Er 3+ -Yb 3+ waveguides were prepared by rf-sputtering technique. The active films were deposited on silica-on-silicon and v-SiO 2 substrates. The parameters of preparation were chosen in order to optimize the waveguides for operation in the NIR region with particular attention to the minimization of losses. The thickness of the waveguides and the refractive index at 632.8 and 543.5 nm were measured by an m-line apparatus. The losses, for the TE0 mode, were evaluated at 632.8 and 1300 nm. Roughness measurements were carried out by means of a stylus profilometer. The structural properties were investigated with several techniques such as Energy Dispersive Spectroscopy and Raman Spectroscopy. All waveguides were single-mode at 1550 nm. An attenuation coefficient equal or lower than 0.2 dB/cm was measured both at 632.8 nm and 1300 nm. The emission 4 I 13/2 → 4 I 15/2 of Er 3+ ion transition with a 40 nm bandwidth was observed upon excitation in the TE0 mode at 981 and 514.5 nm. Back energy transfer from Er 3+ to Yb 3+ was demonstrated by measurement of Yb 3+ emission upon Er 3+ excitation at 514.5 nm. Photoluminescence excitation spectroscopy was used to obtain information about the effective excitation efficiency of Er 3+ ions by co-doping with Yb 3+ ions. Channel waveguides in rib configuration were obtained by etching the active film by a wet etching process. Scanning Electron Microscopy was used to analyze the morphology of the waveguides.