Pulsed laser deposition of rare-earth-doped glasses: a step toward lightwave circuits

Abstract

Pulsed Laser Deposition (PLD) is used to produce Er-doped lead-niobium germanate (PbO-Nb 2 O 5 -GeO 2 ) and fluorotellurite (TeO 2 -ZnO-ZnF 2 ) thin film glasses. Films having high refractive index, low absorption and large transmission are obtained in a narrow processing window that depends on the actual PLD configuration (O 2 pressure ∼a few Pa, Laser energy density ∼2-3 J cm -2 for the results presented in this work). However, Er-doped thin film glasses synthetized at room temperature using these experimental parameters show poor photoluminescence (PL) performance due to non-radiative decay channels, such as a large OHconcentration. Thermal annealing allows improving PL intensity and lifetime (τ PL ), the latter becoming close to that of the parent Er-doped bulk glass. In addition, the use of alternate PLD from host glass and rare-earth targets allows the synthesis of nanostructured thin film glasses with a controlled rare-earth concentration and in-depth distribution, as it is illustrated for Er-doped PbO-Nb 2 O 5 -GeO 2 film glasses. In this case, PL intensity at 1.53 μm increases with the spacing between Er-doped layers to reach a maximum for a separation between Er-doped layers ≥ 5 nm, while τ PL is close to the bulk value independently of the spacing. Finally, the comparison of these results with those obtained for films grown by standard PLD from Er-doped glass targets suggests that nanostructuration allows reducing rare-earth clustering and concentration quenching effects. Downloaded From: http://proceedings.spiedigitallibrary.org/ on 05/24/2017 Terms of Use: http://spiedigitallibrary.org/ss/termsofuse.aspx Proc. of SPIE Vol. 9744 974402-2 Downloaded From: http://proceedings.spiedigitallibrary.org/ on 05/24/2017 Terms of Use: http://spiedigitallibrary.org/ss/termsofuse.aspx