Buried Waveguides in Nd:YFL crystals obtained by femtosecond laser writing under double line approach

D. BIASETTI, E. NEYRA, M.R. TEJERINA, J. RODRIGUEZ VAZQUEZ DE ALDANA, L. ROSO, G.A. TORCHIA

Playa del Carmen

Conferencia; Conference on Laser Ablation (COLA); 2011

In this paper, we present buried waveguides fabricated by fs laser writing in Nd3+ doped YFL crystal under double line approach [3]. The waveguides were made by focusing two consecutive optical breakdown tracks (OBT) separated about 20 mm. To make the optimal OBT, we have focused the fs laser pulses 200 mm below to the surface at intensities above the OB threshold for the material and controlling the writing velocity. The guiding structures were fabricated by using The CPA femtosecond (fs) laser system. We have chosen optimal writing parameters in order to obtain suitable waveguides, using around 3 mJ and writing velocity from 10 m/s up to 50 mm/s. After explore optically the waveguides by end fire coupling, the guiding structures showed well optical performance. Reconstruction of the guiding profiles was retrieved from the modal analysis from the waveguides structures by using BeamProp (RSOFT) commercial software. The spatial distribution of the index increment by taking into account the lower refractive barrier on the OBT region plus the compressed region between the tracks, has been obtained from the fit correctly profiles modes obtained. Finally, optical spectroscopy measurements were also performed in the waveguides, the results showed that the luminescence properties are preserved in the waveguides compared with values obtained for bulk.