Fabrication and characterization of dye doped polyester–polyurethane optical waveguides

A systematic study of the fabrication and characterization of planar optical waveguides based on polyester-polyurethane coatings was done. Mode effective refractive index measurements were performed on a large number of these waveguides fabricated on glass substrates prepared in different conditions. The results indicate that the effect of the dye is to increase the refractive index of the waveguides. The losses in the guides, however, initially decreased from 0.9 to approximately 0.5 dB/cm when the dye concentration was approximately 0.1% but increased drastically (>30 dB/cm) for guides with greater dye concentrations.