Thin organosilicon films for integrated optics

The continued development of integrated optics is heavily dependent upon the availability of materials that are suitable for the construction of thin-film optical circuitry and devices. We report here an investigation of new films made by an rf discharge polymerization process of organic chemical monomers. We concentrate our discussion on films prepared from vinyltrimethylsilane and hexamethyldisilbxane. These films are smooth, tough, pinhole-free, transparent from 0.4 microm to 0.75 microm, and exhibit very low loss (<0.04 dB/cm) for light-wave propagation. More importantly, experiments demonstrate the possibility of controlling the refractive index of the films either by the mixing of the two monomers before deposition or by chemical treatment after the film is deposited. The use of the prism-film coupler for studying the refractive index of each material is discussed in detail.