Propagation loss in polyfluorene waveguides due to nanometer-roughness at their interfaces, studied by amplified spontaneous emission measurements

Abstract

Abstract The propagation loss in single-mode asymmetric waveguides due to interface nanometer-roughness was studied using amplified spontaneous emission (ASE) measurements. Poly(9,9-dioctylfluorene) (F8) was used as the organic gain medium and the structure of the asymmetric waveguide was quartz glass substrate/F8/air. The propagation loss was measured at the ASE wavelength (447 nm) of amorphous F8, and the surface roughness of the substrate and F8 was measured using an atomic force microscope. The propagation losses of F8 waveguides with different F8 slab thicknesses were in good agreement with those calculated using an analytical expression for single-mode asymmetric waveguides with nanometer-roughness interfaces. The results presented herein will be useful for the design of high-performance organic lasers and organic optoelectronic integration systems.