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

DEMIAN BIASETTI, ENRIQUE G. NEYRA, GUSTAVO A. TORCHIA

Conferencia; COLA 2011, SECOND ANNOUNCEMENT 11TH INTERNATIONAL CONFERENCE OF LASER ABLATION; 2011

Nowadays, the femtosecond (fs) laser writing represents a well established technique to achieve optical circuits in a large number of materials either by using passive or active wafers [1-2]. In this paper, we present buried waveguides fabricated by fs laser writing in Nd3+ doped YFL (YLF4) 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 the 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. 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 estimated to fit correctly profiles modes obtained.