Phase-matched second-harmonic generation in a four-layered polymeric waveguide

Phase-matched second-harmonic generation is demonstrated in a four-layered polymeric waveguide structure. The waveguide consists of a glass substrate, a nonlinear-optical active poled polymer with a passive polymer as the waveguide core, and an air cover. The study of the linear-optical properties of this waveguide structure shows the possibility of substantially reducing the waveguide propagation loss. Second-harmonic generation experiments in transmission format show no loss in second-order susceptibility for the poled polymer layer after addition of the passive polymer layer. The independent variation of the thickness of the two polymer layers allows for simultaneous phase matching and tailoring of the second-order nonlinear-optical susceptibility for the optimal overlap integral of the fundamental and the second-harmonic modal field in the waveguide.