Writing Waveguides and Gratings in Silica and Related Materials by Femto-Second Laser

Abstract

With the goal of being able to create various optical glass devices for the telecommunications industry, the effects of 810 nm, femto-second laser radiation on various glasses were investigated. By focusing the laser beam via a microscope objective, transparent but visible, round-elliptical damage lines were successfully written inside high silica, borate, soda-lime-silicate, fluoride and chalcogenide bulk glasses. Micro-ellipsometer measurements of the damaged region in pure and Ge-doped silica glasses showed a 0.01-0.035 refractive index increase, depending on the radiation dose. The formation of several types of defects including Si’E or Ge’E centers, non-bridging oxygen hole centers, and peroxy radicals was also detected. These results suggest that multi-photon interactions are occurring in the glasses and that it is possible to write three dimensional optical circuits in bulk glasses via such a focused laser beam technique. The following is the technique to create waveguides.