NONLINEAR CONTRAWAVE MIXING DEVICES IN POLED-POLYMER WAVE-GUIDES

We investigated efficient surface-emitting second-harmonic-generation devices in poled polymers, using a 4-dimethylamino-4'-nitrostilbene si de-chain polymer. The investigation included characterization of the l inear and nonlinear optical properties of the polymer, design of effic ient surface-emitting second-harmonic-generation devices based on pole d polymers, development of an efficient in-plane poling technique, and demonstration of surface-emitting second-harmonic generation in poled polymers. As a result, strong field inplane parallel poling was succe ssfully performed with poling fields over 300 V/mu m, which led to a l arge nonlinearity of 150 pm/V at 1064 nm (near resonance). A thick cov er layer and a highly resistive substrate were found to be essential f or efficient in-plane poling without breakdown at relatively small fie lds and significant charge injection. We achieved quasi-phase matching in the transverse direction by fabricating nonlinear-linear multilaye r waveguides. Each layer had approximately a 150-nm thickness. The lar gest second-harmonic power conversion efficiency to date in the poled- polymer devices is 0.6%/W cm, which is comparable with those of semico nductor multilayer devices. (C) 1998 Optical Society of America.