Writing Waveguides in Silica-related Glasses with Femtosecond Laser

Abstract

Permanent optical waveguides could be written in bulk glasses with a 800 nm, 120 fs, 200 kHz laser beam. The writing of waveguides ( damage lines ) were carried out by translating the sample parallel to axis of the laser beam. By focusing the laser beam via a microscope objective damage lines which are stable at room temperature and visible under microscope magnification were produced with an increase of refractive index change of 0.04. For several damage lines, the near and far field pattern were observed. From mode profiles of several patterns, it was confirmed the damage lines were employed as an optical waveguide. This new technique gives possibilities in the field of integrated optics, especially for the conception of compact, all-solid-state laser, amplifiers and optical switches.