Structural changes in silica glass after waveguide writing with femtosecond laser pulses

Summary form only given. We have written waveguides as long as 1 cm in silica glasses by tightly focusing femtosecond laser pulses from a regeneratively amplified Ti:sapphire laser (125 fs, 800 nm, 1 kHz) using a microscope objective and translating the glass parallel to the laser beam. For our experiments laser pulse energies range from 0.5-3 /spl mu/J and scan speeds from 10-100 /spl mu/m/s. Smooth lines are clearly visible under an optical microscope, indicating a locally altered index of refraction. The waveguides were analyzed by inspection of their near- and far-field mode profiles.