Sol-gel-based optical waveguides on LTCC substrates

The aim of this work is to test the possibility of sol-gel optical waveguides fabrication on ceramic substrates. The silica sol-gel film is chosen for an optical substrate and cladding and a glaze layer as a material for a waveguide core. The presented paper contains results of examination of the optimal chemical composition and process parameters of sol-gel material and the glaze layer. The refractive indexes and thicknesses of the films have been measured. The technology allows to make waveguide in the grooves made in LTCC substrate. The grooves have 137 mum depth and width variable from 100 mum to 1500 mum. The sol-gel/glaze combination have been used to make stripe waveguides in the grooves.