Waveguide polymeric materials, property

A wide variety of techniques have been employed for the characterization of thin film samples of nonlinear polymeric materials. Many of these are similar to techniques described in the previous section for bulk material characterization, and are employed with thin film samples both to assess differences in material properties in the two physical forms and because certain measurements such as absorption or electro-optic effects may be more easily made in thin film samples. Other techniques are specific to thin film samples in which light can be guided, for which parameters can be measured having no bulk equivalent, such as waveguide scatter or nonlinear mode coupling. 

The refractive index is one of the important optical properties in focus for nanocomposite research at present. Most of the conventional polymers show refractive indices between 1.3 and 1.7 only few polymers exhibit higher refractive indices such as polythiophene with n = 2.12. With the current development of optoelectronic applications the need to adjust the refractive index of polymeric materials is higher than ever before. Potential applications range from creating novel composite lenses for charged coupled devices, optical filters, or reflectors to optical waveguides, optical adhesives or encapsulants, antireflection films, or integration in improved efficiency solar cells. 

In this chapter we will shortly summarize the nonlinear optical properties of macromolecular systems and some of the main experimental techniques for their optical characterization. Some basic optoelectronic patterns will be reported in order to give a brief account of the advances in the realization of active waveguide systems and telecommunication devices based on organic materials. The main optoelectronic devices based on nonlinear optical properties of chromophores in polymeric and hybrid matrices will be illustrated. In particular Mach-Zehnder modulators, microring resonators, switches and wavelength filters will be reviewed. 

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