Writing waveguide in photosensitive glass using ultrafast laser

We experimentally demonstrated the fabrication of different waveguides in Foturan photosensitive glass using femtosecond (fs) laser. The waveguides can be made either by direct writing at energy higher than optical breakdown threshold, or writing at energy lower than the threshold followed by a thermal annealing process. In the first method, permanent microstructural change induced by fs laser results in a refractive index increase. In the second method, thermal annealing caused Ag nanoparticles to be precipitated in the laser writing trace and corresponding increases in refractive index. The waveguides properties were tested by coupling 632.8 nm laser into the waveguide and imaging the output intensity distribution profile.