Perfluorinated polymers for optical waveguides

A long with optical telecommunications systems (see box) (1-3), "integrated optics" (4) and "optical interconnect" (5) technologies are becoming more advanced. The major components of these technologies are photonic integrated circuits (PICs), optoelectronic integrated circuits (OEICs), and optoelectronic multichip modules (OE-MCMs). All the functional devices within these components, including optical and electronic components, are formed or attached on a single planar substrate. Optical signals are transmitted through optical waveguides that connect the components. To implement these technologies, active optical devices such as light sources, optical switches, and optical detectors are needed. Passive optical components such as beam splitters, beam combiners, star couplers, and optical multiplexers are also required. Various materials, including glasses and polymers, have been considered for the construction of these devices. Passive optical components have been fabricated using glass optical waveguides prepared by ion-exchange techniques (6) or by flame hydrolysis deposition and reactive ion etching (7). There are drawbacks to silica-based waveguides, however. First, all the waveguides and passive optical components have to be formed on the substrate before the active optical and electronic devices are attached because of the high processing temperatures needed. For example, temperatures up to 1300 °C are used to consolidate the silica in flame hydrolysis deposition and reactive ion etching. Such temperatures would damage the active optical and electronic devices. Second, glass waveguides are inflexible, making it difficult to process the large waveguides (longer than 30 cm) needed for PICs and OEICs. The development of optical technologies necessitates the fabrication of waveguides after optical and electronic components have been formed and attached. Thus, materials that are flexible and processable at low temperatures are needed. Polymers are one possibility. Polymers will soon be used as waveguide materials for interconnecting passive optical components (8). For integrated circuits and multichip modules, the manufac-