Direct Laser Writing of A Channel Waveguide in Al2O3:Nd Thin Film

The femtosecond laser modification of refractive index in amorphous Al 2 O 3 :Nd thin film prepared by rf magnetron sputtering is investigated. Modifications of the refractive index in a sample with a single Al 2 O 3 :Nd layer and in a sample composed of the Al 2 O 3 :Nd layer and SiO 2 layer on the top were compared. Advantages arising from addition of the SiO 2 layer are shown. The film was patterned in order to form an active waveguide. Waveguide loss and mode composition were investigated experimentally and theoretically. Spectrum and kinetics of luminescence in the region of 1.06 m were measured.