9528021 Dalton Newly developed techniques of femtosecond and picosecond nonlinear optical spectrosocopy (including phase-mismatch spectroscopy) are used to define the contributions made to the optical nonlinearity of pi-electron materials by electronic and nuclear dynamical processes activated by photoexcitation. This information is used to optimize the performance (and define the operational limitations) of devices fabricated from these newly synthesized pi-electron chromophores. Buried channel nonlinear optical waveguides are fabricated in these polymers by a variety of of techniques including photochemical processing and reactive ion etching. A novel multi-color photolithography technique is proposed to solve problems of coupling narrow dimension electro-optic modulator waveguides to larger dimension fiber optic cables. %%% By systematically optimizing chromophore hyperpolarizability, chromophore number density in the polymer lattice, chromophore ordering, and the glass transition temperature of the final polymer lattice, it is anticipated by polymeric materials exhibiting electro-optic coefficients in excess of 50 pm/V and characterized by long term thermal stabilities at temperatures in excess of 125 degrees celsius can be prepared and processed into appropriate integrated polymer/semiconductor photonic/electronic devices. Such materials would represent a significant advance over currently available materials for low frequency modulation applications. ***