Channel wAveguides in ion-exchanged pyrex by direct UV writing

In this paper, we show that UV irradiation can induce a significant refractive index change in Pyrex, a commercial oxide glass which does not contain the most common photosensitiser, germanium. We describe the fabrication of channel waveguides in potassium-ion exchanged Pyrex by UV writing and find the maximum UV-induced change in refractive index to be 1 × 10−3. UV-induced changes in the absorption spectrum are reported and attributed to the formation of defects from iron impurities inherent in the glass. A colour-centre-related model for the observed refractive index change is proposed.