LOSS MECHANISMS IN POLYIMIDE WAVE-GUIDES

Waveguide losses in thin film polyimides using waveguide loss spectros copy and photothermal deflection spectroscopy as a function of cure cy cle and structure were studied. Fluorinated sidegroups on the polyimid e backbone lead to decreases in birefringence and absorption. The prim ary waveguide loss mechanism is absorption, not scattering. Waveguide losses as low as 0.4 dB/cm at 800 nm have been measured. Losses as low as 0.3 dB/cm at 1300 nm can be inferred from the photothermal deflect ion spectroscopy.