Organic and polymer planar optical waveguides

Single‐mode and multi‐mode planar optical waveguides with low loss were fabricated by spin‐coating thin films of poly(vinyl alcohol) (PVAl) and 4‐dihexylamino‐4′‐nitro‐stilbene (DHANS) doped poly(methylmethacrylate) (PMMA) onto glass substrates, and characterised by theoretical analysis and optical guided‐mode measurements. The optical constants of the waveguides were determined with good accuracy by measuring the coupling synchronised angles and fitting them, via a recursion method, into the waveguide dispersion equations. The number of the guided modes observed in these thin films can be controlled by tailoring the film thickness.