Abstract

The field of research called integrated optics has come to encompass all optical devices which utilize guided optical waves and planar processing technology. Work has been directed towards both new and improved devices, and the integration of several devices on a single substrate to perform complex signal processing functions. Three material systems have received considerable attention: glasses, semiconductors such as GaAs and its relatives, and ferro-electrics, in particular LiNbO₃ and LiTaO₃. Each material system has unique properties which makes it most suitable for a particular application. Glass systems have demonstrated the lowest loss optical waveguides but are only suitable for passive device applications. Active devices can be fabricated in both semiconductors and ferroelectrics. The ferroelectrics LiTaO₃ and LiNbO₃ and the III-V semi-conductors have good electrooptic and acoustooptic properties. Semiconductors can also be used for sources and detectors. However, ferroelectrics, which are dielectrics, have lower propagation losses than semiconductors, about 1 dB/cm in strip waveguides compared to greater than 1 cm⁻¹ or 4.3 dB/cm for semiconductors.

© 1978 Optical Society of America