Systems and methods for manipulating light with high index contrast waveguides clad with substances having that exhibit large nonlinear electro-optic constants χ2 and χ3. Waveguides fabricated on SOI wafers and clad with electro-optic polymers are described. Embodiments of waveguides having slots, electrical contacts, and input waveguide couplers are discussed. Waveguides having closed loop structures (such as rings and ovals) as well as linear or serpentine waveguides, are described. Optical signal processing methods, such as optical rectification and optical modulation, are disclosed. Designs having responsivity of less than 1 volt-centimeter are described.