Abstract

The development of integrated optical devices using electrooptic polymers requires an understanding of the effects of fabrication conditions on the optical properties of polymer films. We report on the use of guided mode studies of spin coated planar polymethyl methacrylate waveguides as a technique for characterizing the effects of processing conditions (e.g., polymer solution concentration, viscosity, spin speed, and surface preparation) on the thickness, refractive index, and optical quality of the resultant films. These in situ measurements are supplemented by ellipsometric measurements which are able to confirm the optical constants by out-of-plane measurements. The polymer films are spin coated onto thermally oxidized silicon wafers. Guided wave studies are reported at both 633 and 1064 nm for which a thick (2-μm) oxide lower cladding layer is necessary to prevent absorption in the silicon substrate. The effects of an upper cladding layer on reducing losses due to surface roughness are presented. Semiconductor substrates for optical waveguides are of technological significance not only because of optical interconnection applications but also for the development of micromachining techniques to facilitate coupling of optical signals between fibers and waveguide films. We report on our progress in this area.

© 1989 Optical Society of America