Phase-matched second-harmonic generation in chi (2)-inverted Langmuir-Blodgett waveguide structures

Phase-matched second-harmonic generation by mode conversion in a new waveguide structure fabricated by the Langmuir-Blodgett (LB) technique is demonstrated. The nonlinear optically active part of the waveguide consists of two LB layers with opposite sign to the nonlinear optical coefficient d₃₃. This configuration leads to a large improvement of the overlap integral as compared to conventional waveguides. In first experiments conversion efficiencies up to 1%W^-1cm^-2 have been obtained.