Fabrication of inorganic GeO₂:SiO₂channel waveguides by ultraviolet imprinting technique

The authors demonstrate the effective waveguiding channel formation inside an ∼3 μm thick photosensitive GeO2(20%):SiO2(80%) planar slab waveguide film prepared using the sol-gel technique by the direct ultraviolet (UV) imprinting technique. This is possible because of the ability to induce large refractive index change (∼10-3) in the films by the UV radiation. Channel waveguides with various refractive index values have been fabricated. The measured modal profiles of the waveguides match well with the simulation results. The simplicity of the direct UV imprinting technique is also shown by the fabrication of a 1 × 2 multimode-interference 3 dB light splitter in one single processing step.