During the past few years, new concepts for nonlinear optical signal processing have spurred interest in nonlinear optical devices based on third-order susceptibilities. As a result, there has been an increase in materials fabrication and processing development, particularly in semiconductors. For many applications) 1, 2 these semiconductor materials are particularly attractive because of their large nonlinearities and their compatibility with existing opto-electronic technology. However, the resonant-type processes responsible for the large nonlinear response of these materials yield absorption coefficients that cause thermal problems and also limit the speed of response (recovery) of the material to optical signals. Thus the driving force behind some of the nonlinear organic materials development is the need for good optical quality, highly nonlinear optical materials with low absorption coefficients.