Flexible thin-film polymer waveguides fabricated in an industrial roll-to-roll process.

The fabrication of flexible low-loss, thin-film, foil-based polymer waveguides with grating couplers employing a high-volume industrial roll-to-roll process is demonstrated. The embossed waveguides feature propagation losses of less than 1 dB/cm (633 nm, TE polarization), bending losses of 0.4-0.8 dB/360° for bending radii as small as 2 mm, and grating coupling efficiencies of up to 25%. In addition, the waveguides possess a thermo-optic coefficient of -1.58×10(-4) 1/°C. The fabricated waveguides are promising candidates for short-distance data communication as well as for sensing applications.

Integrated polymer-based Mach-Zehnder interferometer label-free streptavidin biosensor compatible with injection molding.

We report the development of a Mach-Zehnder interferometer biosensor based on a high index contrast polymer material system and the demonstration of label-free online measurement of biotin-streptavidin binding on the sensor surface. The surface of the polyimide waveguide core layer was functionalized with 3-mercaptopropyl trimethoxy silane and malemide tagged biotin. Several concentrations of Chromeon 642-streptavidin dissolved in phosphate buffered saline solution were rinsed over the functionalized sensor surface by means of a fluidic system and the biotin-streptavidin binding process was observed in the output signal of the interferometer at a wavelength of 1310 nm. Despite the large wavelength and the comparatively low surface sensitivity of the sensor system due to the low index contrast in polymer material systems compared to inorganic material systems, we were able to resolve streptavidin concentrations of down to 0.1 µg/ml. The polymer-based optical sensor design is fully compatible with cost-efficient mass production technologies such as injection molding and spin coating, which makes it an attractive alternative to inorganic optical sensors.