Polymer waveguides for sensor applications.

Strip waveguides have been fabricated in a thin film consisting of a mixture of poly(methylmethacrylate) (PMMA) with a UV-sensitive photoinitiator. The film is deposited by spincoating on a PMMA substrate. As an example for a sensor application, the waveguides were doped with the pH-indicator dye bromophenol blue, which changes the optical behaviour of the lightguide in interaction with a humid environment like an aqueous liquid or a gas.