Absorption and Scattering in Low-Loss Polymer Optical Waveguides

The absolute absorption spectra of low-loss optical waveguides, together with their intrinsic and extrinsic scatterings, were measured in the near infrared region. Photothermal deflection spectroscopy was used to measure the full absorption spectra of a series of fluorinated crosslinked polymers. Assignment of -CH(3), -CH(2)-, and -OH overtones as well as combinations of overtones were made using the theory of anharmonic vibrations based on a Morse potential for local modes. Details of the molecular potential are given. The total attenuation in slab waveguides made with these polymers as measured using a prism-coupling technique and compared to the absolute absorption. Losses due to the material itself and those due to processing are quantified.