Optical waveguides induced in inorganic glasses by a femtosecond laser

In an attempt to write optical waveguides in bulk glasses, photo-induced refractive index changes were continuously produced by focusing an ultra-short laser pulse through a microscope objective and translating the sample parallel to the axis of the laser beam. The resulting linear refractive index changes were written inside the bulk glasses along the path traversed by the focal point of the laser. From field intensity distributions in the output of guided light for these waveguides, we demonstrated that permanent optical waveguides could be successfully formed in various types of glass. In addition, through analyzing the near-field pattern with a CCD camera, we confirmed that single mode waveguides of the graded index type could be formed by a writing technique using an ultra-short laser pulse. (C) 1998 Elsevier Science B.V.