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F2-laser microfabrication of buried waveguide structures in transparent glasses

Buried optical waveguides have been fabricated directly in pure bulk fused silica with a novel high-resolution 157-nm optical processing system. Refractive index changes of > 10-4 were induced within the small focal volume of large numerical-aperture optics, removing the need for ultrafast laser interactions. Single-mode guiding was inferred from Gaussian-like near-field and far-field intensity distributions of 635-nm guided light. The results demonstrate a useful extension of writing buried 3D refractive index structures inside glasses with nanosecond duration UV lasers.