Fabrication of low loss polyimide optical waveguides using thin-film multichip module process technology

A simple, wet chemical patterning process for the fabrication of low loss waveguides using photosensitive polyimides is described. Optically transparent, fluorinated polyimides are modified by co-polymerizing a low concentration of photocrosslinking groups into the backbone. The polyimides can then be patterned into arrays of channels, ribs, or Y branches, by UV exposure through a photomask followed by wet chemical development. Sidewall smoothness and sidewall profiles can be controlled by varying exposure and development conditions. The resulting polyimide waveguides are low loss and can be coupled into an optical fiber by end-fire coupling. Results on channel guide coupling, propagation, and loss are described