The fabrication and assessment of optical waveguides in poly (p-phenylenevinylene/poly (2,5-dimethoxy-p-phenylenevinylene) copolymer

Abstract

Optical waveguides have been fabricated using a copolymer of poly( p-phenylenevinylene) PPV and poly(2,5-dimethoxy- p-phenylenevinylene) PDMeOPV via a precursor route. Controlled conversion of the precursor copolymer can give partially conjugated higher band gap or fully conjugated lower band gap regions, and the difference in refractive index is used to define diffused-channel waveguides. The spatial resolution of the process is limited only by the diffusion of acid around the capping layer, and by the lithography. We have made lines in 0.15μm thick films as narrow as 1μm and have demonstrated optical waveguiding in 4μm wide lines. Slab waveguides and diffused-channel waveguides have been assessed by prism and end-fire coupling at 633nm and 780nm. The anisotropy in the refractive index, and optical propagation losses have been measured.