We identify two states of stress induced in waveguides fabricated by femtosecond lasers in fused silica and show how they can be relieved by annealing. In-plane stress and stress concentration are revealed through birefringence and loss measurements. Another kind of laser-induced stress appears in the form of swelling of the glass surface when waveguides are written near the surface and is a manifestation of confined rapid material quenching. By annealing the sample we reduce the losses by ~30% (at 633 nm) and decrease the birefringence by a factor of 4 in fused silica.
© 2004 Optical Society of America
V. R. Bhardwaj, P. B. Corkum, D. M. Rayner, C. Hnatovsky, E. Simova, and R. S. Taylor, "Stress in femtosecond-laser-written waveguides in fused silica," Opt. Lett. 29, 1312-1314 (2004)