Waveguide shaping and writing in fused silica using a femtosecond laser

Fused silica waveguides were written and reshaped with an 800-mn amplified femtosecond laser in a lateral writing configuration. The asymmetry of the waveguide shape and the index profile was partially corrected through multiple scans shifted by 1 or 2 /spl mu/m. Following the careful adjustment of both laser pulse energy and writing speed, the resulting waveguides exhibited substantial reduction in propagation and coupling losses by more than 50% in the C-band.