Photoinduced refractive-index changes in TiO2-doped silica optical waveguides on silicon substrate

Abstract

For the first time, refractive-index changes are desribed which are due to laser irradiation in a Mach–Zehnder interferometer composed of TiO2-doped silica optical waveguides on an Si substrate. A maximum refractive-index change of about 1.0 × 10−5 is obtained around 1.5μm at an Ar+ laser throughput power of 2.1 W and an irradiation time of 1 h even though the concentration of TiO2 is very low (about 0.3mol.%).