Polyimide lightguides integrated with a planar polymer detector

Planar lightguides were fabricated from polyimides containing two hexafluoroisopropylidene groups. In multimode lightguides of these fluorinated polyimides loss values below 0.5 dB/cm can be realized using optimized curing conditions. After curing, this material is insoluble in organic solvents so that multilayer films can be prepared. As an example we combined these polyimides with a planar organic photoconductive layer to form an integrated photodetector. In the system poly-(N-vinyl carbazole) (PVK) - trinitrofluorenone (TNF) a photoconductive complex is formed which is sensitive in the visible spectral region. This compound is deposited from a solution of chlorobenzene/tetrahydrofuran on the substrate between thin gold electrodes. The photoconductivity of these planar detector layers is studied using He-Ne-Laser light. An increase of photoconductive sensitivity is observed for high TNF concentrations. © 1990 SPIE.